# Need Help With 1 Hp Motor



## JR49

My H.F. 4X6 bandsaw has the original 1 HP motor that it came with. Don't know how much use it's had as I got it used. Today, while cutting a steel plate 5" wide by 1" thick (this took longer than any piece since buying it), when it got almost to cutting through the bottom, the blade stopped. I assume, as it was cutting through a tooth caught and jammed the blade. I lifted up on the saw and the blade began moving again. I figured that the belt was slipping, because surely, the motor has enough power to slip the belt, especially since I run the belt pretty loose to make speed changes easy. But, to my surprise, it was not the belt, the motor was stopping, and as soon as I lifted the blade up it started turning again. I tried this a few more times and each time the motor stalled rather than slip the fairly loose belt. Are these H.F. motors that underpowered? The motor temp was about 138* F. with a laser thermometer, if that makes a difference. Is this motor junk? I would think with a little more power the blade should have pulled right through the cut. Does this motor have replaceable brushes, and would worn brushes cause the lack of power? I can probably fix it If you electrical gurus tell me what to fix. If need be, I can get a new motor, cause the saw is in really good shape, but I'd rather fix this one if I can. Please Help! Thanks, JR49                                                                                            
EDIT,  Forgot to say, blade is 10-14 TPI, so there were plenty of teeth in the cut


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## JimDawson

The first thing I would look at is the motor wiring.  If it is a dual voltage motor, is the motor  wired for the voltage that you are running?  A motor wired for 240 will run on 120 but at much reduced power, and certainly may run hot.  But 138F is not really that hot.  The other possibility is that you lost one of the windings and in that case to only practical option is to replace the motor.  It would cost more to repair the motor than it would to replace it.


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## JR49

JimDawson said:


> The first thing I would look at is the motor wiring.  If it is a dual voltage motor, is the motor  wired for the voltage that you are running?  A motor wired for 240 will run on 120 but at much reduced power, and certainly may run hot.  But 138F is not really that hot.  The other possibility is that you lost one of the windings and in that case to only practical option is to replace the motor.  It would cost more to repair the motor than it would to replace it.



Will do Jim, and thanks.  So can I assume that worn brushes wouldn't cause this power loss ?  JR49


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## RJSakowski

For a cut that deep into a 5"  piece, it is common for the chips to jam the blade.  Before deciding the motor is toast, try it on a shallower cut.  

Motors, particularly inexpensive motors are often optimistically rated.  My 4x6 has a 3/4 hp motor and will stall occasionally when cutting large pieces.

Which pulley configuration are you running on?  For a piece of steel that size, you probably would be better off running with the smallest drive pulley.  It will slow your cutting down but you will gain quite a bit on torque.  You can also back off on the cutting pressure which should reduce jamming.  My saw has an adjustable spring to accomplish that. 

Finally, if your cut is almost through and you are still jamming, you can rotate your work  so the 5" dimension is vertical.  Your previous cut will guide the blade to keep your cut straight and the saw will cut through much faster.

If you don't have the manual for the saw, here is the link. 
http://manuals.harborfreight.com/manuals/93000-93999/93762.pdf 

Here is the link for the Grizzly 4x6.  The saws are all pretty much alike and Grizzly does a better job with their manual.  
http://cdn2.grizzly.com/manuals/g0622_m.pdf

Bob


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## JimDawson

JR49 said:


> Will do Jim, and thanks.  So can I assume that worn brushes wouldn't cause this power loss ?  JR49



That is an induction motor, it doesn't have brushes.


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## JimDawson

This motor would be the replacement for it.  http://www.harborfreight.com/1-HP-Agricultural-Farm-Duty-Motor-68288.html

If I recall correctly, my 4x6 had a 1/2 HP motor on it and would always slip the belt if the blade hung.  Your 1HP should never stall.  I'm guessing it's a dual voltage motor and is wired for 240.


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## JR49

RJSakowski said:


> Which pulley configuration are you running on?



Thanks so much Bob, I new I could depend on Jim to give me the electrical side of this problem, and now you have given me a lot more to think about. The saw was running on the middle pulleys (120 sfm), so I could have gone to the lower 80sfm pulley. I would have thought (wrongly, I guess) that even a 1/2 HP motor would slip the pulley in the somewhat loose belt, rather than stop spinning, but hey, what do I know.  Not much about elect. motors, I guess, and this is the first metal cutting saw I've ever used.  So,  If you say your saw stalls sometimes, I guess that's just the way it is.  I will try all suggestions tomorrow.  One thing still confuses me though.  Why would they give it two higher speeds If the motor can't use them?  Thanks again,  JR49

EDIT,  Just had another thought Bob, I've read posts where guys complain about stripping a tooth or two when using a blade with too few teeth on thin material.  My motor would certainly stall out, and possibly blow a breaker before it would pull hard enough to break a tooth.  What do ya think?


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## RJSakowski

JR, I use my saw to cut a variety of materials including plastic and aluminum and, in fact, mostly use the highest speed. A 1" x 5" slab of steel is a challenge for a little saw like this.  The 4 x 6 capacity is just stating the maximum size of work.  It doesn't imply that the saw is going to easily slice through a 4 x 6 bar of steel.

Bob


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## JimDawson

Like I said above, I don't recall ever stalling my 1/2 HP, it always slipped the belt.  But like you I ran the belt a tad loose so it would slip rather than fry the motor if it jammed when I walked away from it on a long cut.

I burnt up more than one belt, and always kept a spare on hand.


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## JR49

Jim, I can't believe I did this at 10:30pm.  Just went out and took a picture, using a flashlight, so quality is poor.  Correct me If I'm wrong but  this is the only info on the motor, and I think it is saying that this is only a 120 volt motor.  Will check back in the morning.  JR49


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## John Hasler

JR49 said:


> Just had another thought Bob, I've read posts where guys complain about stripping a tooth or two when using a blade with too few teeth on thin material. My motor would certainly stall out, and possibly blow a breaker before it would pull hard enough to break a tooth. What do ya think?


The momentum of the spinning motor would suffice to break one tooth before the motor stalled.


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## RJSakowski

I agree with John.  By the time the motor stalls, the tooth is gone.


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## kwoodhands

JR49 said:


> My H.F. 4X6 bandsaw has the original 1 HP motor that it came with. Don't know how much use it's had as I got it used. Today, while cutting a steel plate 5" wide by 1" thick (this took longer than any piece since buying it), when it got almost to cutting through the bottom, the blade stopped. I assume, as it was cutting through a tooth caught and jammed the blade. I lifted up on the saw and the blade began moving again. I figured that the belt was slipping, because surely, the motor has enough power to slip the belt, especially since I run the belt pretty loose to make speed changes easy. But, to my surprise, it was not the belt, the motor was stopping, and as soon as I lifted the blade up it started turning again. I tried this a few more times and each time the motor stalled rather than slip the fairly loose belt. Are these H.F. motors that underpowered? The motor temp was about 138* F. with a laser thermometer, if that makes a difference. Is this motor junk? I would think with a little more power the blade should have pulled right through the cut. Does this motor have replaceable brushes, and would worn brushes cause the lack of power? I can probably fix it If you electrical gurus tell me what to fix. If need be, I can get a new motor, cause the saw is in really good shape, but I'd rather fix this one if I can. Please Help! Thanks, JR49
> EDIT,  Forgot to say, blade is 10-14 TPI, so there were plenty of teeth in the cut



I have the same saw, I would expect the blade to stall cutting thick steel plate.I drip cutting oil into the cut and if the blade stalls ,lift the saw til the blade runs full speed.I rarely change speeds,leave it on the middle pulley.If you cut a lot of thick steel,use the slow speed pulley .
One other thing,especially since you bought the saw used.Change the transmission oil. There are 6 hex bolts on the cover.Remove them and the cover.Get as much of the goop out of the case as you can.Check manual for oil,I believe it calls for 120 weight oil.I bought it at a Napa store.Makes a big difference,especially in cold weather where the motor won't turn over if it is cold in the shop.
I doubt that the motor needs work. My saw is 9 years old ,motor still running strong.

mike


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## JimDawson

JR49 said:


> Jim, I can't believe I did this at 10:30pm.  Just went out and took a picture, using a flashlight, so quality is poor.  Correct me If I'm wrong but  this is the only info on the motor, and I think it is saying that this is only a 120 volt motor.  Will check back in the morning.  JR49
> 
> 
> 
> 
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> View attachment 111487



Yup, you are correct, 120V only.  But the HP marking is a bit optimistic on their part, that is a 1/3 HP motor (maybe a 1/4), not 1 HP.  6.4 AMPs at 120V = just a bit less than 1/3 HP. a 1 HP motor would draw about 13.6 amps.

That explains a lot.  That motor would stall easily.

.


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## markba633csi

Is there a capacitor on that motor Jim? Maybe it's toast-
Mark S.
Mt. View, Ca


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## JimDawson

markba633csi said:


> Is there a capacitor on that motor Jim? Maybe it's toast-
> Mark S.
> Mt. View, Ca



According to the picture on the manual, yes.  You could be right, I hadn't thought of that.  Good call!


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## RJSakowski

Unless it is a capacitor run motor, the capacitor is not in the circuit after the motor starts.  The symptom of a  bad  capacitor  is the inability to start turning.  If the motor starts to stall, the start circuit would kick in again and give some additional torque but at that point, it is probably too late anyway.


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## RJSakowski

Another thought, if you are using an extension cord, make sure it is heavy enough.  A light gauge cord will decrease the amount of power delivered to an already anemic motor.  A 20ft, 16 ga. extension cord will drop your available power by 4% at 6 amps.  Every little bit helps (or hurts, depending on your point of view).


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## RJSakowski

To add to Jim's comment concerning the hp rating, 6.4 amps x 120 volts is 768 watts which is just over 1 hp.  but this is input power.  What you are interested in is output power which has to take into account losses in the motor.  Some machine manufacturers use the input power in their specs because it makes the machine look better.  To make matters worse, some use peak input power.  This occurs briefly during startup or when the motor stalls, neither condition being useful in assessing the machine capability.  My old Hoover vacuum blatantly claims 3.1 peak hp while the motor plate states 10.1 amps which is about 1.6 hp input.  Conversely, my 4x6 saw motor states 3/4 hp output with a current draw of 12.5 amps which equates to about 2hp input and is a lot closer to reality.

The takeaway on this is when you are evaluating a machine, know which power figure the manufacturer is quoting.  If possible, try to get the run current spec.  The input power is .16 x the input current and the output power will never be as great as the input.  Jim's figure of about 35% efficiency is probably a good rule of thumb.

Bob


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## JimDawson

RJSakowski said:


> To add to Jim's comment concerning the hp rating, 6.4 amps x 120 volts is 768 watts which is just over 1 hp.  but this is input power.  What you are interested in is output power which has to take into account losses in the motor.  Some machine manufacturers use the input power in their specs because it makes the machine look better.  To make matters worse, some use peak input power.  This occurs briefly during startup or when the motor stalls, neither condition being useful in assessing the machine capability.  My old Hoover vacuum blatantly claims 3.1 peak hp while the motor plate states 10.1 amps which is about 1.6 hp input.  Conversely, my 4x6 saw motor states 3/4 hp output with a current draw of 12.5 amps which equates to about 2hp input and is a lot closer to reality.
> 
> The takeaway on this is when you are evaluating a machine, know which power figure the manufacturer is quoting.  If possible, try to get the run current spec.  The input power is .16 x the input current and the output power will never be as great as the input.  Jim's figure of about 35% efficiency is probably a good rule of thumb.
> 
> Bob


Good explanation Bob, thank you.


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## JR49

This is great!  Getting a Discussion going with lots of members (thanks all), about the ins and OUTS of a cheap H.F. saw.  Based on all the replies, I think  I will leave it as is, for now, start using the slower speed for more torque, and not expect too much out of this vastly overrated motor.  Kwoodhands, I did change the trans. oil when I got it. Thanks for that, I actually used 140wt., as temp rarely gets below 40 F here. I do have a question for you, doesn't using cutting oil get oil and chips all over the wheels and inside the cover?  Thanks to all,  JR49


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## coffmajt

You asked about the three pulley positions.  If you are cutting aluminum or brass you can use the highest speed/ conversely when cutting thick steel you need the slowest speed.  Good luck with the motor == Jack


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## 4GSR

I have one of these saws I've been using for about 10 years now.  The issue of the motor stalling is there and will happen.  As others have said toward the end of the thread is to run it in the slowest speed.  I agree 100%, that is the speed I run mine in.  I cut everything up to including 4145HT in rounds up to about 4-1/2".  I've even cut up some iron and aluminum into rectangular sections of nearly 7" square on my 4 x 6 saw. 
One thing I have notice on the input shaft of the gear box, it is very hard to turn and it gets hot from running.  This has a big affect on the motor stalling using it in the higher speeds.  I don't think you are having a problem with the motor.  It's more an mechanical issue...


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## coffmajt

Sounds like you have a bearing tight in the gearbox. On my old saw that was similar I removed all the old poor quality grease and replaced it with 90 w hypoid gear oil. Jack


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## JR49

JimDawson said:


> This motor would be the replacement for it. http://www.harborfreight.com/1-HP-Agricultural-Farm-Duty-Motor-68288.html


 
Jim, or whoever has more knowledge than I (nearly all).   Although, thanks to the guidance I got here, I will not be replacing the motor presently,  you sent me  link to a motor that I could use as a replacement, without even seeing the saw.  Could please share how you determine if a motor will be a correct fit to replace an existing motor in any machine (bandsaw lathe drill press etc.).  Please include:  When a spec says motor spins CW, or CCW, is that  with shaft facing you or away from you?


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## JimDawson

JR49 said:


> Jim, or whoever has more knowledge than I (nearly all).   Although, thanks to the guidance I got here, I will not be replacing the motor presently,  you sent me  link to a motor that I could use as a replacement, without even seeing the saw.  Could please share how you determine if a motor will be a correct fit to replace an existing motor in any machine (bandsaw lathe drill press etc.).  Please include:  When a spec says motor spins CW, or CCW, is that  with shaft facing you or away from you?



Great questions!

I was going by the stated 1 HP, and my knowledge.  Those saws all take a NEMA 56 frame size motor (or possibly its rough metric equivalent).  In hind site, I would probably recommend a 1/2 hp motor, rather than the 1 hp.  No point in tearing up your gearbox.

Motors in general are sold by frame size, the most common up to 1 hp is the NEMA 56.  I can't remember the frame number for the metric (IEC) motor in that general range.  Once you go above 1 HP, then there are other frame sizes.  For instance the 5HP on my compressor is a 182T frame.  The frame specification will give you, shaft size, the mounting footprint, and physical size.  All motors in a given frame will have the same specification regardless of HP.  

Most motor rotation is listed facing the shaft, but who knows with Asian motors.  If it is not reversible, the rotation is normally clearly stated.  Most aftermarket motors are reversible anyway, so it really doesn't make any difference.


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## chevytrucking

I have smoked a motor on one of these cutting a thick piece of aluminum. Prior to that I had the centrifugal switch fuse together. The motors can have problems. and the factory rating of 1hp is joke, but the physical dimensions should you need to replace it are the same as a NEMA 56 3/4 hp. I've got a couple of videos up that show problems I've had with my motors. The videos cover other things too, but I talk about motor problems in both of them. Hope it helps.


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## jahjah

It's probably a cheap induction motor with a run capacitor that has failed.  Since the capacitors are smaller than what is commonly used on a better motor and actually available, you may have to modify the cover to get a new one to fit.  They are about $5-10 and a electric motor shop can supply.  In general, teeth do not shed on a plate unless it is seriously low quality and has contaminants in it like you might find in a bed frame.  My guess, you have overheated the cheap capacitor through no fault of yours.  BTW, a saw that is blueprinted with a good blade will stall the motor before the blade will come off or strip teeth.  Teeth are normally removed by cutting a hard thin wall tubing or getting something jammed between the deflector and the blade.  Little wedges that you are cutting off have an uncanny ability to find the opening.


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## FREDROSSE

JR49 said:


> My H.F. 4X6 bandsaw has the original 1 HP motor that it came with. Don't know how much use it's had as I got it used. Today, while cutting a steel plate 5" wide by 1" thick (this took longer than any piece since buying it), when it got almost to cutting through the bottom, the blade stopped. I assume, as it was cutting through a tooth caught and jammed the blade. I lifted up on the saw and the blade began moving again. I figured that the belt was slipping, because surely, the motor has enough power to slip the belt, especially since I run the belt pretty loose to make speed changes easy. But, to my surprise, it was not the belt, the motor was stopping, and as soon as I lifted the blade up it started turning again. I tried this a few more times and each time the motor stalled rather than slip the fairly loose belt. Are these H.F. motors that underpowered? The motor temp was about 138* F. with a laser thermometer, if that makes a difference. Is this motor junk? I would think with a little more power the blade should have pulled right through the cut. Does this motor have replaceable brushes, and would worn brushes cause the lack of power? I can probably fix it If you electrical gurus tell me what to fix. If need be, I can get a new motor, cause the saw is in really good shape, but I'd rather fix this one if I can. Please Help! Thanks, JR49
> EDIT,  Forgot to say, blade is 10-14 TPI, so there were plenty of teeth in the cut


 This motor on the HF 4x6 saw is only 1/3 HP, far below  1 HP, and is minimal quality.  I have been using the same setup for over 20 years, with no problems, although I know the HF imported motor is bottom of the barrel stuff.  This is a brushless induction motor, and you should just buy a USA made 1/3 HP replacement and be done with problems here.  Be sure to check the gearbox lubrication level, and bearings all around.  With moderate care this saw will continue to give good service.


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## Smithdoor

I have a lot of steel cutting  band saws over year most had 1/3 to 1/2 one very lard band saw had 3/4" motor
This saw only needs a good 1/3 to 1/2 hp motor
I have same saw with that motor I am waiting for day it dies and have the replacement on the shelf
I have cut lot bars 3/4 X 5 and 5" round stock with old I had it only had 1/3 motor  form post tool about 25 years ago. Note I sold this and had to buy one from HF 7 years ago 

Dave



JR49 said:


> My H.F. 4X6 bandsaw has the original 1 HP motor that it came with. Don't know how much use it's had as I got it used. Today, while cutting a steel plate 5" wide by 1" thick (this took longer than any piece since buying it), when it got almost to cutting through the bottom, the blade stopped. I assume, as it was cutting through a tooth caught and jammed the blade. I lifted up on the saw and the blade began moving again. I figured that the belt was slipping, because surely, the motor has enough power to slip the belt, especially since I run the belt pretty loose to make speed changes easy. But, to my surprise, it was not the belt, the motor was stopping, and as soon as I lifted the blade up it started turning again. I tried this a few more times and each time the motor stalled rather than slip the fairly loose belt. Are these H.F. motors that underpowered? The motor temp was about 138* F. with a laser thermometer, if that makes a difference. Is this motor junk? I would think with a little more power the blade should have pulled right through the cut. Does this motor have replaceable brushes, and would worn brushes cause the lack of power? I can probably fix it If you electrical gurus tell me what to fix. If need be, I can get a new motor, cause the saw is in really good shape, but I'd rather fix this one if I can. Please Help! Thanks, JR49
> EDIT,  Forgot to say, blade is 10-14 TPI, so there were plenty of teeth in the cut


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## 9Sec93LX

Harbor Freight tools rate their motors using Shetland Ponies as their horses of choice, not Clydesdales.

Be careful trying to replace your motor with a NEMA (American) sized replacement motor.
The original motor is METRIC sized (frame size currently eludes me), a Nema 56 frame motor has a 5/8" shaft and a Nema 48 frame is 1/2"diameter.
Harbor Freight motors are something like .550" or so (not quite 9/16") so your pulleys won't swap without a sleeved bushing inside it or turning down the 5/8" rotor of the 56 frame one.
Also the mounting bolts are completely in the wrong spot for easy swapping, but this is a machinists website after all so it should be easily remedied.
I believe these are a Capacitor RUN motor, NOT capacitor Start, so as someone else mentioned it might be bad and causing you grief.

The 138* temperature is normal for an electric motor under a load. I didn't see a spec on the nameplate you posted, but MOST motors have a "Temperature Rise of 40*C" (CENTRIGADE) which  is 104* F.
You add the Temp. Rise to the Ambient (Air) temperature and you get the average working temperature of the motor.
Some motors actually have a 50*C rating (they get hot enough to fry an egg on but are fairly uncommon in use).
Good Luck
Tommy


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## Mr. Fixit

I read your question with interest. HF is bad about stating hp. Based on the name plate it consumes electric for 1.03 hp .that is theoretical hp based on 100% eff.
Using the standard of 83% that would be .850 hp. That motor is not capable of yielding those results. Based on my experience with HF motors the other people  are being generous with .25 hp.
I have a 1942 drill press that is 1/2 hp and the current  draw is 7.8 amps, the 1920's ? drill press that is 1/4 hp draws 4.6 amp ,and my 1950's Delta/Milwaukee band saw draws 5.0 for 1/3 hp. I ordered many years ago a  1/2 hp grinder from HF, I could hold the grinding wheel and turn it backwards while on. Don't waste your money on repairs, you would have the same hp. Yes you will squeal  when pricing another motor. If it has a frame size you are in luck as that how to get a motor that will fit., if not you will the bench to center line of shaft and the mounting feet hole spacing. Sorry I didn't have better news.


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## Mad Monty

I took a look at my own HF bandsaw motor, and here is what I learned:  under the hump on the side, there is a start capacitor, necessary to get it going from a dead stop.  It is not a run capacitor, which if bad, could have explained your results. 

I verified it was a run capacitor by cutting its leads.  The motor hummed but didn't start moving.  If I substitute a much lower capacitance (5uF instead of 35uFd that comes with it) to simulate a failing capacitor, same thing.  But if I then give it a manual shove (under no load, i.e., blade not touching work), it starts up and reaches normal speed.  When I let it down on the work (aluminum plate 1/2") it cuts through like butter, as usual.  This scenario is typical of capacitor start motors.  Bottom line: if it starts up fine, it ain't your cap. 

Odds are pretty high the motor is shot, as other problems almost always have other symptoms, which you haven't mentioned (example - most bad switches, wire junctions, power cords and plugs give you intermittent /erratic power, making the motor speed up, slow down, etc., and you might even hear/see/smell the arc - which  by the way, can be dangerous to the equipment, not to mention your workshop and yourself.

My bandsaw has given me consistent, decent performance.  I buy better blades for it (from Enco, not HF).  The motor is fine for the job.  You can do better, but not at the price.


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## Garyg

My busy bee band saw looks similar. Mine would stall also . Turned out to be the brass gear in the transmission. It was so worn the steel worm gear and the brass gear would jam and stall the motor. One day I had left it to cut and it failed to shut off. The motor was really hot and the brass gear was  stripped completely. The oil looked like it was liquid brass.


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## Smithdoor

FYI
USA made motor are full Horse Power for 24 hours. Some China motors are made like vacuum clearer  lock rotor hp
The other part is look for SF 1.1 or higher on the motor this will give extra power when need

Dave


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## 9Sec93LX

Mad Monty said:


> I took a look at my own HF bandsaw motor, and here is what I learned:  under the hump on the side, there is a start capacitor, necessary to get it going from a dead stop.  It is not a run capacitor, which if bad, could have explained your results.
> 
> I verified it was a run capacitor by cutting its leads.  The motor hummed but didn't start moving.  If I substitute a much lower capacitance (5uF instead of 35uFd that comes with it) to simulate a failing capacitor, same thing.  But if I then give it a manual shove (under no load, i.e., blade not touching work), it starts up and reaches normal speed.  When I let it down on the work (aluminum plate 1/2") it cuts through like butter, as usual.  This scenario is typical of capacitor start motors.  Bottom line: if it starts up fine, it ain't your cap.
> 
> Odds are pretty high the motor is shot, as other problems almost always have other symptoms, which you haven't mentioned (example - most bad switches, wire junctions, power cords and plugs give you intermittent /erratic power, making the motor speed up, slow down, etc., and you might even hear/see/smell the arc - which  by the way, can be dangerous to the equipment, not to mention your workshop and yourself.
> 
> My bandsaw has given me consistent, decent performance.  I buy better blades for it (from Enco, not HF).  The motor is fine for the job.  You can do better, but not at the price.


 
 A 35 MFD capacitor is NOT a start capacitor, it IS a run capacitor. Start capacitors have a much higher mfd rating and it is always given as a range of values (124-149mfd, 149-174mfd, 174-208mfd, etc.). For a 1hp motor it would be in the neighborhood of 124-149 mfd or 149-174 mfd it depends on the original engineers calculations when the motor is built. Just look under the cover of your average 1hp sprinkler or pool pump. The motor didn't start because it had an open circuit when you removed the capacitor or you used a 5 mfd capacitor that it is not designed to use. Run capacitor values are more critical than starting capacitor values, because they remain in the circuit at all times. Even a slight change of 35mfd to say a 40 mfd will affect the way the motor works. If of the wrong value the motor will run hot, lack torque and generally not perform well at all. It IS quite possible that the mans RUN capacitor is weak and causing his problem. Any electric motor shop should have a "Capacitor tester" and be able to tell him if his is within spec. Sorry.  If you don't believe me Google it for yourself.


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## mzayd3

Here is an interesting web page in relation to bandsaw blade physics.  It may not help with this exact situation, but is interesting nonetheless.

http://woodgears.ca/bandsaw/resaw.html


Sent from my iPad using Tapatalk


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## Mad Monty

9Sec93LX said:


> A 35 MFD capacitor is NOT a start capacitor, it IS a run capacitor. Start capacitors have a much higher mfd rating and it is always given as a range of values (124-149mfd, 149-174mfd, 174-208mfd, etc.). For a 1hp motor it would be in the neighborhood of 124-149 mfd or 149-174 mfd it depends on the original engineers calculations when the motor is built. Just look under the cover of your average 1hp sprinkler or pool pump. The motor didn't start because it had an open circuit when you removed the capacitor or you used a 5 mfd capacitor that it is not designed to use. Run capacitor values are more critical than starting capacitor values, because they remain in the circuit at all times. Even a slight change of 35mfd to say a 40 mfd will affect the way the motor works. If of the wrong value the motor will run hot, lack torque and generally not perform well at all. It IS quite possible that the mans RUN capacitor is weak and causing his problem. Any electric motor shop should have a "Capacitor tester" and be able to tell him if his is within spec. Sorry.  If you don't believe me Google it for yourself.



Maybe I'm missing something here, and if you can tell me what it is, I would appreciate it.  

I'll grant you that most start caps are higher mFd than run caps.  But I just don't see how the OP's cap could be a run cap, for two reasons:  

First, it isn't the value of the capacitor that _makes_ it a run capacitor, but how it is used in the motor.   The start capacitor is only in the circuit until it reaches typically 75% of rated speed.  The value of the capacitance depends on many things, primarily frequency, motor design, and start-up torque required.  The first is fixed, the second beyond this discussion, but I think the third, start-up torque, may explain why a relatively low 35 mFd could work as a start capacitor.  Assuming you don't start the saw with the blade pressed against the stock, it doesn't take much torque to get it going; you're starting it with no load.  Contrast this with sprinkler or pool pump, where you're working against the water from the moment the shaft starts to turn.  That's where you need a lot of capacitance and that's where you find it.  Same thing with winches, elevators, and cranes:  you're starting under a heavy load.

The second reason I'm not convinced is the empirical evidence:  the removal (or weakening of the cap) affected only the start-up performance.  It had no effect on full speed operation under load.   Perhaps I wasn't clear:  with the cap out of the circuit, or significantly lower capacitance, the motor hums but does not start, but if I give it a spin, it picks up speed and in a few seconds is up to full speed.  I can use it to cut stock at the same rate as when the right cap is in the circuit.  From this, it seems clear to me that (1) the circuit was not open (if it were, the motor would not have hummed or run at all), and (2) the cap is a start capacitor (as it was necessary to start the motor) and not a run capacitor (as the motor ran with full speed and power without it).  This pattern is the hallmark of a bad start cap (easily verified via your favorite search engine).

Finally, I took your suggestion to Google the ranges for start and run caps.  Within the first couple of hits I came across a much lower end range than yours: "Most start capacitors have ratings of 50-1200 uf" - which is to say, not _all _start capacitors are above 50.  So his 35 mFd is not an unreasonable value for a start cap.   [http://www.capacitorformotor.com/motor_capacitor.html]

Am I missing something?  Maybe you have an better explanation for the results of my "experiment"?


----------



## 9Sec93LX

Mad Monty said:


> Maybe I'm missing something here, and if you can tell me what it is, I would appreciate it.
> I'll grant you that most start caps are higher mFd than run caps. But I just don't see how the OP's cap could be a run cap, for two reasons:
> First, it isn't the value of the capacitor that _makes_ it a run capacitor, but how it is used in the motor. The start capacitor is only in the circuit until it reaches typically 75% of rated speed. The value of the capacitance depends on many things, primarily frequency, motor design, and start-up torque required. The first is fixed, the second beyond this discussion, but I think the third, start-up torque, may explain why a relatively low 35 mFd could work as a start capacitor. Assuming you don't start the saw with the blade pressed against the stock, it doesn't take much torque to get it going; you're starting it with no load. Contrast this with sprinkler or pool pump, where you're working against the water from the moment the shaft starts to turn. That's where you need a lot of capacitance and that's where you find it. Same thing with winches, elevators, and cranes: you're starting under a heavy load.
> The second reason I'm not convinced is the empirical evidence: the removal (or weakening of the cap) affected only the start-up performance. It had no effect on full speed operation under load. Perhaps I wasn't clear: with the cap out of the circuit, or significantly lower capacitance, the motor hums but does not start, but if I give it a spin, it picks up speed and in a few seconds is up to full speed. I can use it to cut stock at the same rate as when the right cap is in the circuit. From this, it seems clear to me that (1) the circuit was not open (if it were, the motor would not have hummed or run at all), and (2) the cap is a start capacitor (as it was necessary to start the motor) and not a run capacitor (as the motor ran with full speed and power without it). This pattern is the hallmark of a bad start cap (easily verified via your favorite search engine).
> Finally, I took your suggestion to Google the ranges for start and run caps. Within the first couple of hits I came across a much lower end range than yours: "Most start capacitors have ratings of 50-1200 uf" - which is to say, not _all _start capacitors are above 50. So his 35 mFd is not an unreasonable value for a start cap. [http://www.capacitorformotor.com/motor_capacitor.html]
> Am I missing something? Maybe you have an better explanation for the results of my "experiment"?


 

   I understand your confusion on the matter Monty and while I am NOT an electrical engineer I'll try my best to explain my point.
My father started our motor shop in 1960 (the year I was born) so I can only tell you what we have experienced first hand on the job.
    The HF motor in question is what's called a "Permanent Split Capacitor" (PSC) motor.
It uses the Start AND run winding AT ALL TIMES in order to boost the HP rating of the motor (usually done on less expensive motors that do NOT require excessive starting torque).
    They do this because Iron (motor laminations) is expensive and so is Copper for windings (Although I'd venture a guess that this HF motor used Copper COLORED Aluminum windings). So by utilizing both sets of coils together the motor is smaller (cheaper to manufacture) and uses slightly less Amperage due to the increased resistance of both windings vs. using only the Run windings.
    A PSC motor is used on applications like fans or drill presses and bandsaws and Not on a water pump because as you correctly stated the pump starts under a heavy load and the saw is allowed (or should be allowed) to come up to full speed before it's lowered onto the material to be cut.
    By removing or changing the capacitor you are effectively deleting the Start winding from the picture completely, which is why you need to roll it over to start it.
    With the capacitor removed you could roll the motor over in EITHER direction and it will run equally well (for the most part). Bandsaw probably won't CUT very well in reverse though I'm guessing. LOL

   The major difference between Start caps and Run caps is the Start caps are rated for intermittent duty and the Run caps are rated for continuous duty.
The easiest (NOT SAFEST) way to prove my point would be to insert a KNOWN Start cap in your motor and run it.
KA-BOOM will ensue in a very short order as the cap overheats and fails.

I've included a link to a wiring diagram that shows how the circuit is connected and should help you to visualize what I'm saying.
I hope this clarifies things for you, if not LMK.
Tommy

Skip down to mid page for the PSC motor diagram.

http://eng-electric.blogspot.se/2012/08/microchip-ac-induction-motor_11.html


----------



## JR49

You guys have raised this discussion/debate, to a level that's way over my head.  I'm not complaining, I actually love reading these type of posts, and am glad I was the one to start the ball rolling.  SO, now I'm hopping someone will dumb this down enough for me to get 1 answer.  Will it help to replace the cap. or not ?  A quick review:  My motor starts, and spins up to max rpm every time. When cutting a 5"wide, 1"thick steel plate, a tooth caught while breaking through, and the motor stopped rather than spin the belt.  this was on the middle pulleys (120sfm).  Yesterday, I spent over 3 hrs. cutting 1-5/16" dia. round bar, using the top pulleys (80 sfm) , and no problems except once when the blade got pinched (my fault).  But this time, (in the lowest speed mind you) the motor kept turning and the small pulley slipped in the belt (somewhat loose belt tension had not been changed since the plate cut).  If changing the cap., which is the limit of elect. motor ability, will give it a little more power, so that it won't stall in the 120spm speed, I will do it. Otherwise,  I will follow others advise, and keep it in low speed.  Anyone got an answer?  Thanks,  JR49


----------



## 9Sec93LX

JR49 said:


> You guys have raised this discussion/debate, to a level that's way over my head.  I'm not complaining, I actually love reading these type of posts, and am glad I was the one to start the ball rolling.  SO, now I'm hopping someone will dumb this down enough for me to get 1 answer.  Will it help to replace the cap. or not ?  A quick review:  My motor starts, and spins up to max rpm every time. When cutting a 5"wide, 1"thick steel plate, a tooth caught while breaking through, and the motor stopped rather than spin the belt.  this was on the middle pulleys (120sfm).  Yesterday, I spent over 3 hrs. cutting 1-5/16" dia. round bar, using the top pulleys (80 sfm) , and no problems except once when the blade got pinched (my fault).  But this time, (in the lowest speed mind you) the motor kept turning and the small pulley slipped in the belt (somewhat loose belt tension had not been changed since the plate cut).  If changing the cap., which is the limit of elect. motor ability, will give it a little more power, so that it won't stall in the 120spm speed, I will do it. Otherwise,  I will follow others advise, and keep it in low speed.  Anyone got an answer?  Thanks,  JR49


 
Sorry about that JR,
    It was never my intention to go this far with the discussion and hijack your thread.
For that I apologize.
To answer your question as quickly as possible. If you remove the capacitor and take it to your local electric motor repair shop they will have a "capacitor tester" in their inventory of tools.
There they can "test" your capacitor to see if it is within tolerance.
If it IS within tolerance, changing it will NOT help your problem.
If it is NOT within spec, changing it WILL help your problem.
You can NOT change capacitor values randomly expecting it to "BOOST" motor torque (Sorry).
The capacitor is engineered to work with the windings that the motor came with and they work as a team.
Doing otherwise would be like trying to reinvent the wheel.
Simple, RIGHT....LOL
Good Luck
Tommy


----------



## Mr. Fixit

JR49 said:


> You guys have raised this discussion/debate, to a level that's way over my head.  I'm not complaining, I actually love reading these type of posts, and am glad I was the one to start the ball rolling.  SO, now I'm hopping someone will dumb this down enough for me to get 1 answer.  Will it help to replace the cap. or not ?  A quick review:  My motor starts, and spins up to max rpm every time. When cutting a 5"wide, 1"thick steel plate, a tooth caught while breaking through, and the motor stopped rather than spin the belt.  this was on the middle pulleys (120sfm).  Yesterday, I spent over 3 hrs. cutting 1-5/16" dia. round bar, using the top pulleys (80 sfm) , and no problems except once when the blade got pinched (my fault).  But this time, (in the lowest speed mind you) the motor kept turning and the small pulley slipped in the belt (somewhat loose belt tension had not been changed since the plate cut).  If changing the cap., which is the limit of elect. motor ability, will give it a little more power, so that it won't stall in the 120spm speed, I will do it. Otherwise,  I will follow others advise, and keep it in low speed.  Anyone got an answer?  Thanks,  JR49


Please help us a little. I' not to get int cap start or cap run. Is there a large cover in the side of the motor? If so is . so what is the value of the capacitor?. If it a capacitor start motor which I believe it is,the value will be larger number rated in micro-farads. If the motor comes up to full speed as soon as it energized the capacitor is good. Try and remove the end housing bell from from the motor carefully,be sure you place a scratch across the bell and housing This help in getting the mounting feet in the same plane. Do not try and pry it with  a large tool. If Yugo can get a flat screw driver between the to pieces just pry a little and work your way around. After it is remove the flyweight from the end and underneath the flyweight is a flat metal switch, ensure that that switch is stuck together get it apart and take some very fine emery or sand paper and hold it between the switch contacts an smooth them out. The motor speed is fixed and changing pulley arrangement will only  effect the cutting speed.
Try and run the motor without any load and see if it comes up full speed.  check to see if the gear box turns freely ,if it doesn't  that issue will have to addressed as a separate issue. I know that this sound undoable  but take your time  and let us know what you found. I will start with what  info you provide to go to the next step. I will use technical terms and language but in simple and understandable English. I am retired so don't worry about the time. As I like to say: I'm a thousand miles from nowhere and time don't matter to me.


----------



## Mr. Fixit

Mr. Fixit said:


> Please help us a little. I'll not to get into cap start or cap run. Is there a large cover in the side of the motor? If so is . so what is the value of the capacitor?. If it a capacitor start motor which I believe it is,the value will be larger number rated in micro-farads. If the motor comes up to full speed as soon as it energized the capacitor is good. Try and remove the end housing bell from from the motor carefully,be sure you place a scratch across the bell and housing This help in getting the mounting feet in the same plane. Do not try and pry it with  a large tool. If Yugo can get a flat screw driver between the to pieces just pry a little and work your way around. After it is remove the flyweight from the end and underneath the flyweight is a flat metal switch, ensure that that switch is stuck together get it apart and take some very fine emery or sand paper and hold it between the switch contacts an smooth them out. The motor speed is fixed and changing pulley arrangement will only  effect the cutting speed.
> Try and run the motor without any load and see if it comes up full speed.  check to see if the gear box turns freely ,if it doesn't  that issue will have to addressed as a separate issue. I know that this sound undoable  but take your time  and let us know what you found. I will start with what  info you provide to go to the next step. I will use technical terms and language but in simple and understandable English. I am retired so don't worry about the time. As I like to say: I'm a thousand miles from nowhere and time don't matter to me.


----------



## JR49

9Sec93LX said:


> Sorry about that JR,
> It was never my intention to go this far with the discussion and hijack your thread.
> For that I apologize.



    Absolutely NO apology needed, Tommy, the little I know about machining, I got from reading posts (mostly right here), that I didn't understand, but eventually, some of It sunk in.  Someday, thanks to guys like you, I will post an answer to a novice's question about motors, and he will think I'm an expert, ya right.  About getting more power, I'm not trying to hot rod it, I only meant that if it isn't up to factory spec because of a bad cap, I would replace it to get back any lost power.  I am planning to find an electric motor repair place.  Final question,  would you expect them to test my cap. for free or charge me?  Caps. are pretty cheap, (I think), so if they charge, I might save by just buying a new one, and try it.  What do you think?  Thanks  JR49


----------



## Mr. Fixit

JR49 said:


> You guys have raised this discussion/debate, to a level that's way over my head.  I'm not complaining, I actually love reading these type of posts, and am glad I was the one to start the ball rolling.  SO, now I'm hopping someone will dumb this down enough for me to get 1 answer.  Will it help to replace the cap. or not ?  A quick review:  My motor starts, and spins up to max rpm every time. When cutting a 5"wide, 1"thick steel plate, a tooth caught while breaking through, and the motor stopped rather than spin the belt.  this was on the middle pulleys (120sfm).  Yesterday, I spent over 3 hrs. cutting 1-5/16" dia. round bar, using the top pulleys (80 sfm) , and no problems except once when the blade got pinched (my fault).  But this time, (in the lowest speed mind you) the motor kept turning and the small pulley slipped in the belt (somewhat loose belt tension had not been changed since the plate cut).  If changing the cap., which is the limit of elect. motor ability, will give it a little more power, so that it won't stall in the 120spm speed, I will do it. Otherwise,  I will follow others advise, and keep it in low speed.  Anyone got an answer?  Thanks,  JR49


Sorry to correct my own reply, I'll make it a lot easier. Remove belts from machine, next energize the motor and after it comes up to speed, deenrgize the motor and listen for a click ( usually the click is noticeable) as motor slows down to a stop. This will help decide if is a motor problem or gearbox problem. please reply  and let me know which direction to go. I see that HF has the saw on sale for $260.00 this will help on how much repairs are.


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## RJSakowski

Given that the motor is highly overrated by the manufacturer and is probably closer to 1/3 hp, the 35 mfd capacitor is not far from reality.  On the the other hand, 35 mfd is within the ballpark for a permanent split capacitor motor as well.

To determine whether the motor is a capacitor start motor or a permanent split capacitor motor, listen for the click of the centrifugal switch as the motor winds up or down.  If you hear it, it is a capacitor start motor; if there is no click then it is a permanent split capacitor motor motor.  

If it is a capacitor start motor, the capacitor is not in the circuit during cutting and if the saw bogs down, it is most likely due to being overloaded trying to make a cut in 5" of steel.  It sound like changing to the low speed pulley arrangement has solved your problem.  It this point, I would expect the the motor is performing normally.  It is on the small side for this application and the solution would be to install a larger motor.  However, be aware that doing so may overload other components of the saw.  If you only use the saw infrequently, it may be best to live with the inadequacies.

Bob


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## JR49

I just went out and did as you guys suggested.  First I took the belt off, then turned motor on and off at least 5 times, and every time both starting, then letting it get up to full rpm, and stopping, and listening carefully until the motor came to a stop, there was no click either heard or felt (I held my hand on the back cover).  So, if I'm understanding what has been said it is not a start cap., it is a run cap..  So, if the "run cap." is faulty, then this motor will develop less power than it did when new, and the cap. was not faulty, (even if the power, when new was a lot less than H.F. claims).  Remember, I'm not trying to hot rod it, but if it is less then it should be, and a new inexpensive cap can make "all that it can be", than I will do that.  If not, then I'm happy with it as is.  At 66, hacksaws are out of the question.  Thanks again,  JR49


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## 9Sec93LX

JR49 said:


> Absolutely NO apology needed, Tommy, the little I know about machining, I got from reading posts (mostly right here), that I didn't understand, but eventually, some of It sunk in.  Someday, thanks to guys like you, I will post an answer to a novice's question about motors, and he will think I'm an expert, ya right.  About getting more power, I'm not trying to hot rod it, I only meant that if it isn't up to factory spec because of a bad cap, I would replace it to get back any lost power.  I am planning to find an electric motor repair place.  Final question,  would you expect them to test my cap. for free or charge me?  Caps. are pretty cheap, (I think), so if they charge, I might save by just buying a new one, and try it.  What do you think?  Thanks  JR49


JR,

MOST motor shops won't charge you to test a capacitor if you bring them the capacitor in hand (on the assumption that if it's bad you buy your new cap. from THEM.
When you call them to get directions, you can inquire if they'll be any charge and if they have a cap. of said value already in stock.
Of course if they have to disassemble your motor to remove it, labor charges will apply.
Most caps are indeed very inexpensive, but if it's good why waste your money?

One more tip (oh NO I know...) replacement Run caps are usually quite a bit larger than the undersized OEM Chinese jobs, because replacement caps are rated @370V for a larger Safety Factor and the HF one probably isn't even marked as to it's original voltage rating.
So you will HAVE TO make a new enclosure for the new cap (if larger) as you NEVER want to leave any Cap. exposed (see my earlier Ka-Boom comment).


----------



## 9Sec93LX

JR49 said:


> I just went out and did as you guys suggested.  First I took the belt off, then turned motor on and off at least 5 times, and every time both starting, then letting it get up to full rpm, and stopping, and listening carefully until the motor came to a stop, there was no click either heard or felt (I held my hand on the back cover).  So, if I'm understanding what has been said it is not a start cap., it is a run cap..  So, if the "run cap." is faulty, then this motor will develop less power than it did when new, and the cap. was not faulty, (even if the power, when new was a lot less than H.F. claims).  Remember, I'm not trying to hot rod it, but if it is less then it should be, and a new inexpensive cap can make "all that it can be", than I will do that.  If not, then I'm happy with it as is.  At 66, hacksaws are out of the question.  Thanks again,  JR49





RJSakowski said:


> Given that the motor is highly overrated by the manufacturer and is probably closer to 1/3 hp, the 35 mfd capacitor is not far from reality.  On the the other hand, 35 mfd is within the ballpark for a permanent split capacitor motor as well.
> 
> To determine whether the motor is a capacitor start motor or a permanent split capacitor motor, listen for the click of the centrifugal switch as the motor winds up or down.  If you hear it, it is a capacitor start motor; if there is no click then it is a permanent split capacitor motor motor.
> 
> If it is a capacitor start motor, the capacitor is not in the circuit during cutting and if the saw bogs down, it is most likely due to being overloaded trying to make a cut in 5" of steel.  It sound like changing to the low speed pulley arrangement has solved your problem.  It this point, I would expect the the motor is performing normally.  It is on the small side for this application and the solution would be to install a larger motor.  However, be aware that doing so may overload other components of the saw.  If you only use the saw infrequently, it may be best to live with the inadequacies.
> 
> Bob


RJ,
Great suggestion to listen for the Starting switch click. 

JR,
   You got it.
See my lengthy explanation(s) were NOT over your head after all. Class Dismissed. LOL


----------



## Mr. Fixit

Good morning: I am enjoying this discussion and I will not let an electrical problem defeat me. I worked 30 years in the natural gas plant I as an electrical instrument and electrician although we used 480vac the  trouble shooting is the same. I see that you tried what was suggested, which is great so now down to the motor. If you would post  pictures of the motor it will  help. I'm just a little older than you and I understand about the purchase of a saw-and  I do not add any new power tools to my shop. I went online and read the owners manual and the pictures show a capacitor start motor. The repair parts just say motor.  Again pictures will help and if you unplug saw and remove capacitor cover on the side and let us know the value.


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## Mr. Fixit

I tend to agree with J.R. If the saw cuts fine in higher speeds the motor and gearbox are good.  Less tension on the belt will help. Man I am enjoying this discussion.  Let us know what how you are doing


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## Mr. Fixit

Just curios  that the saw cuts on higher speed but not at low speed.Are the pulleys set like? Agine just curios.


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## JR49

Mr. Fixit said:


> Just curios that the saw cuts on higher speed but not at low


You have it backwards.  The saw cuts fine at the lowest speed.  That would be with the belt in the highest position which uses the smallest pulley on motor shaft, and largest pulley on gear box shaft.  JR49


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## Mr. Fixit

That is my mistake I believed that it would not cut at low speed. Thanks for the reply. I always say run it till its broke.


----------



## Mad Monty

9Sec93LX said:


> A 35 MFD capacitor is NOT a start capacitor, it IS a run capacitor. Start capacitors have a much higher mfd rating and it is always given as a range of values (124-149mfd, 149-174mfd, 174-208mfd, etc.). For a 1hp motor it would be in the neighborhood of 124-149 mfd or 149-174 mfd it depends on the original engineers calculations when the motor is built. Just look under the cover of your average 1hp sprinkler or pool pump. The motor didn't start because it had an open circuit when you removed the capacitor or you used a 5 mfd capacitor that it is not designed to use. Run capacitor values are more critical than starting capacitor values, because they remain in the circuit at all times. Even a slight change of 35mfd to say a 40 mfd will affect the way the motor works. If of the wrong value the motor will run hot, lack torque and generally not perform well at all. It IS quite possible that the mans RUN capacitor is weak and causing his problem. Any electric motor shop should have a "Capacitor tester" and be able to tell him if his is within spec. Sorry.  If you don't believe me Google it for yourself.


So - my final word on the start/run question:  9Sec93LX, you were right, I was wrong:  I now agree that it's a run cap.  (It even says so right on it ("RUNNING CAPACITOR.")    A more thorough check of the industrial catalogs shows nearly all the start caps are above 100, and the runners below.  Thanks for setting me straight.
BTW JR49 - you've probably already figured how to get the cap out, but if not:  it's really easy to get to because it's under an external plastic cover, just pull the two philips head screws.  Usually you can pull off the quick-disconnects from the cap, but if not, you can cut the wires right at the cap so you may have enough not to have to splice them.  If you don't have any QD's that fit, the motor repair surely will.  Good luck!


----------



## 9Sec93LX

Mad Monty said:


> So - my final word on the start/run question:  9Sec93LX, you were right, I was wrong:  I now agree that it's a run cap.  (It even says so right on it ("RUNNING CAPACITOR.")    A more thorough check of the industrial catalogs shows nearly all the start caps are above 100, and the runners below.  Thanks for setting me straight.
> BTW JR49 - you've probably already figured how to get the cap out, but if not:  it's really easy to get to because it's under an external plastic cover, just pull the two philips head screws.  Usually you can pull off the quick-disconnects from the cap, but if not, you can cut the wires right at the cap so you may have enough not to have to splice them.  If you don't have any QD's that fit, the motor repair surely will.  Good luck!


 
No Problemo Monty.
JR,
Motor caps are NON-polarized so you don't need to mark which lead goes where, they are interchangeable, which simplifies things for you.
Can't wait to hear the results of the Cap. test so we can see if that's really your issue or just an underpowered HF motor.
Tommy


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## 4GSR

Humm,  That's odd to have a run capacitor without a start capacitor on a motor....  You generally don't get into run capacitors on a motor until you get into the 3-5 HP and higher range.......


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## 9Sec93LX

4gsr said:


> Humm,  That's odd to have a run capacitor without a start capacitor on a motor....  You generally don't get into run capacitors on a motor until you get into the 3-5 HP and higher range.......


 

See my earlier comment on PSC (Permanent Split Capacitor) motors.
It's actually very common on smaller inexpensive motors, as the engineers use BOTH sets of windings in an attempt to give the motor more guts. Not to mention the additonal cost savings by not have to use both a Governor (rotating Starting switch) and a stationary Starting switch, that's Harbor Freight for you. How else do you think they sell the things so cheap? Besides Slave labor wages of course. LOL




9Sec93LX said:


> I understand your confusion on the matter Monty and while I am NOT an electrical engineer I'll try my best to explain my point.
> My father started our motor shop in 1960 (the year I was born) so I can only tell you what we have experienced first hand on the job.
> The HF motor in question is what's called a "Permanent Split Capacitor" (PSC) motor.
> It uses the Start AND run winding AT ALL TIMES in order to boost the HP rating of the motor (usually done on less expensive motors that do NOT require excessive starting torque).
> They do this because Iron (motor laminations) is expensive and so is Copper for windings (Although I'd venture a guess that this HF motor used Copper COLORED Aluminum windings). So by utilizing both sets of coils together the motor is smaller (cheaper to manufacture) and uses slightly less Amperage due to the increased resistance of both windings vs. using only the Run windings.
> A PSC motor is used on applications like fans or drill presses and bandsaws and Not on a water pump because as you correctly stated the pump starts under a heavy load and the saw is allowed (or should be allowed) to come up to full speed before it's lowered onto the material to be cut.
> By removing or changing the capacitor you are effectively deleting the Start winding from the picture completely, which is why you need to roll it over to start it.
> With the capacitor removed you could roll the motor over in EITHER direction and it will run equally well (for the most part). Bandsaw probably won't CUT very well in reverse though I'm guessing. LOL
> 
> The major difference between Start caps and Run caps is the Start caps are rated for intermittent duty and the Run caps are rated for continuous duty.
> The easiest (NOT SAFEST) way to prove my point would be to insert a KNOWN Start cap in your motor and run it.
> KA-BOOM will ensue in a very short order as the cap overheats and fails.
> 
> I've included a link to a wiring diagram that shows how the circuit is connected and should help you to visualize what I'm saying.
> I hope this clarifies things for you, if not LMK.
> Tommy
> 
> Skip down to mid page for the PSC motor diagram.
> 
> http://eng-electric.blogspot.se/2012/08/microchip-ac-induction-motor_11.html


----------



## 4GSR

Mad Monty said:


> I took a look at my own HF bandsaw motor, and here is what I learned:  under the hump on the side, there is a start capacitor, necessary to get it going from a dead stop.  It is not a run capacitor, which if bad, could have explained your results.
> 
> I verified it was a run capacitor by cutting its leads.  The motor hummed but didn't start moving. ...............



You cut the leads to the starting capacitor... of course it's not going to start.  What you need to do is bypass the capacitor, connect the leads together.  This will complete the circuit allowing the motor to start.  Put a larger mfd rated start capacitor in the circuit, this will eliminate any starting problems...


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## 9Sec93LX

Deleted comment


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## dlane

I keep several USA made motors on hand so I can throw out the chi motors that have any problem.
I get them from Craig's list, garage sales , cheep $5-10 . I have a 1hp craftsman table saw motor on my 4x6 works good


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## JR49

First, let me say thank you to all the great folks who participated in this thread.  I apologize for taking so long to get this figured out, but I had a bad experience with my radiation  treatments that set me back about 2 weeks.  Anyway, feeling better now, I cut the 2 wires going to the cap. and brought it to be tested.  The tech. guy was really nice and offered to test it for me even though he said he would not have anything that small to sell me.  It tested fine (40 micro whatevers)  so there was no reason to try to find a replacement, so tomorrow I will splice the wires back together and run the saw in the slowest speed, with what is definitely a very underpowered motor.  But like I said before, It sure beats the old man powered hack saw!!  Thanks again,  JR49


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