# Enco Mill - motor takes a few tries to get to full speed



## tcweb (Dec 14, 2018)

Hello experts, I have my Enco mill (RF30) up and running and have an annoying problem.

When I turn the switch (forward or reverse, doesn't matter), the motor immediately kicks on and comes up to about 1/3 speed, then stalls or "pulses" at about that speed.
It must pull a ton of current, as I have managed to trip the breaker once.

I turn it off, wait a few seconds, try again.  Usually after 3-4 tries it fires up and goes to full speed.  The motor is a 2HP, currently wired for 110v, since I don't have a 220v option in my garage.   The motor is a dual capacitor model.

I'm wondering if it could be something like a bad run capacitor?  I'm not a motor expert by any means.  The contacts on the switch look OK, and all connections are tight, as far as I can tell.  Since it does fire up and run smoothly after a few tries, that should mean that the coils are OK, right? 

Any advice is appreciated.  If you are a fellow RF30/Enco owner, and have a source for a motor or motor parts, let me know.  The current motor appears to be chinese. I believe it's the original motor that came with the mill.  

-Tom


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## CluelessNewB (Dec 14, 2018)

I don't have an RF30 but I have worked on many motors.  My guess is starter cap.   They are cheap and not hard to replace.


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## tcweb (Dec 14, 2018)

Thanks.  Motors that have dual-caps...would both need to be replaced?  Since the motor fires up right away (to partial speed), before it stalls, would that indicate that the starter cap is OK, but the run cap may be faulty?  I"m not an expert on how motors with a run cap (dual capacitors) actually work.


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## CluelessNewB (Dec 14, 2018)

I would replace both caps while you have it apart.  If it's more than 10 years old I would probably change bearings also although that has nothing to do with your problem, that's a bit more work than the caps.


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## warrjon (Dec 14, 2018)

I had a 2hp single phase motor on a 12x36 lathe and it used to eat start caps ($80 each here). There is a centrifugal switch in the motor that disconnects the start cap, if this is faulty and / or sticking intermittently it WILL take out the start cap before you can turn the motor off.

Remove the start cap (cut one wire) and turn the motor on, does it start (albeit slower) and run. If it does the run cap is good and your issue is the start cap. I removed the start cap and ran the motor without it, just takes the motor a little longer to come up to speed, as long as the motor is not starting under load like in a compressor.


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## tcweb (Dec 14, 2018)

Thank you both.  I just pulled the covers off, and took pictures of the caps, so I can try to find replacements.
Someone had labelled them "start" and "run" with a sharpie.  the "run" cap looks like one side is a bit flattened, not sure what that's about.


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## kvt (Dec 14, 2018)

I have not looked under my cover,   I have a RF30 2hp wired for 110.  Has one hump cover on it.   
I can take it off and look if needed.   but is sounds like you may have a diff motor on yours.


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## tcweb (Dec 14, 2018)

is your motor Chinese?   I believe my Enco was made in Taiwan back in the 80's.  (but I'm not 100% sure).  Here are some pictures of the capacitors.  Do I need to match them exactly, or can there be some variance from these specs?  

The first pic is the run cap.  Second is the start cap.


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## markba633csi (Dec 14, 2018)

On the voltage rating: match or higher, never less. On the capacitance value, try to get close to the original value.  More is a bit better than less. For example, for the 35 uF one, 40 would be better than 30. 
mark


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## tcweb (Dec 14, 2018)

Thanks.  Does the "CD60" and "CBB60" represent the size of the cap?  Or do I just have to do my best to find one that fits inside the covers, adding a spacer as needed?


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## tcweb (Dec 14, 2018)

So these could work (if needed):  Seems like they make them in capacitance ranges. (400uF - 480uF).  Or maybe that's just the tolerances they can reach in China.  

https://www.ebay.com/itm/CBB60-35MF...h=item2cb75198a8:g:OCwAAOSwux5YUlcC:rk:7:pf:0

https://www.ebay.com/itm/CD60-Motor...=item2cbdd651d5:g:OBYAAOSwcUBYR7Ww:rk:25:pf:0


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## warrjon (Dec 14, 2018)

Yep they will do the job.

If they are physically smaller you can glue a small piece of foam to the cap to stop it rattling around DO NOT wrap the whole cap or it may overheat.

Motor capacitors - The manufacturer selects the capacitor value to provide a phase shift of 90° between the start and run windings, this is a good compromise between starting torque and current through the winding. Increasing the capacitance will increase torque and current draw, it is usually best to go slightly lower in C for a start capacitor, although ±10% is usually ok.


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## markba633csi (Dec 14, 2018)

uF (microfarad) is the capacitance value, the "u" is actually supposed to be a greek "mu" (micro) but most keyboards don't have a "mu" symbol, including mine. A "mu" looks like a u with a little tail
mark


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## Tozguy (Dec 15, 2018)

tcweb said:


> Thanks.  Does the "CD60" and "CBB60" represent the size of the cap?  Or do I just have to do my best to find one that fits inside the covers, adding a spacer as needed?



Yes use a spacer if necessary. 
In my case I could not find a capacitor that was small enough to fit under the OEM cover. Some new caps that were rated properly but were too large in size were used. I made a new cover to house the new caps. The new bigger caps seem to be lasting better than the old ones.
Note that repeated short starts and stops can be hard on the start cap.


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## warrjon (Dec 15, 2018)

markba633csi said:


> uF (microfarad) is the capacitance value, the "u" is actually supposed to be a greek "mu" (micro) but most keyboards don't have a "mu" symbol, including mine. A "mu" looks like a u with a little tail
> mark



The µ symbol is alt230, When I worked in the calibration Lab we had to use the correct symbols so there are a couple etched into my brain.


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## markba633csi (Dec 15, 2018)

Hmm doesn't seem to work for me, but I'm using a Linux distro  on a ThinkPad T400
mark


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## Mark Needham (Dec 16, 2018)

Your Motor is running up on Start. switching off.
There is no Run Circuit.!!!!!
https://electronics.stackexchange.c...ved-in-a-single-phase-cap-start-cap-run-motor

Check there is a circuit. terminals are secure etc. on the RUN winding.
Mark Needham


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## mcdanlj (Dec 24, 2018)

markba633csi said:


> Hmm doesn't seem to work for me, but I'm using a Linux distro  on a ThinkPad T400
> mark



Off topic, but... On Linux, check your keyboard settings for your compose key. I find that on "Keyboard configuration → Layouts → Options..." but that depends on the windowing environment you are using; see GNOME or KDE documentation.  I have mine set to right alt key, so I type "right-alt / u" to get "µ" — that's not holding down the right alt key, it's typing it like a normal key. There are lots of options there, like "compose-key - >" to get "→" and "compose-key ^ 1" to get "¹" and so forth. Once you know to do a search including "compose key" you'll find lots of useful information. ☺ ← "compose-key : )" "compose-key < -"


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## markba633csi (Dec 24, 2018)

Thanks I'll check with the Peppermint forum for specifics on that topic
Mark


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## tcweb (Dec 25, 2018)

I started a motor question, and an IT question broke out.    (too funny, I'm in IT)

I will let everyone know how this is ultimately resolved.  Waiting for the run cap to show up on the slow boat from China, and then I'll swap them one at a time.

Merry Christmas everyone, and thanks for all of the help.


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## talvare (Dec 25, 2018)

From your initial description of the problem, it sounds like you likely have a sticking, dirty or defective centrifugal switch. This is a pretty common problem on capacitor start motors. Many times it can be resolved just by removing the motor end bell and cleaning the switch mechanism. Just some food for thought.

Ted


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## tcweb (Dec 25, 2018)

Ted, I will (reluctantly) take the motor off and see if I can get it apart...

Tom


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## Chris Hamel (Dec 27, 2018)

I have an enco gl 30 b  built in 1972.  It definitely has a centrifugal switch.  I can hear it.  Something to check on the mill in question would be to listen for the switch.  It you don't hear it at startup, you should definitely hear it when the motor slows down.  If it is sticking on, it would cause all kinds of trouble.  The start windings pull a lot of current.


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## tcweb (Jan 25, 2019)

OK, I have the new caps, and the motor is on my bench.  Warming up.  It's freaking 5 degrees (F) here.

My next challenge - getting the pulley off the motor.  Looks like two set screws at 90 deg to each other.  3mm hex, seems to be close fit.  They are TIGHT.  Any tips for getting them out? I have them soaking in penetrating fluid right now.   Even with the set screws out, my guess is that the aluminum pulley is not going to want to just slide off the motor shaft. 

Any tips for not damaging the pulley?  Or the motor shaft?   Use wedges to try to force it off?

-Tom


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## Tozguy (Jan 26, 2019)

tcweb said:


> It's freaking 5 degrees (F) here.



Cool is kewl, less chance of things overheating 

The motor pulley should have a keyway. Set screws should only be to keep the pulley aligned. Once the screws are loose the pulley should slide OK. I'd use a puller if the shaft is rusted or the pulley is seized with crud.


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## tcweb (Jan 26, 2019)

Got the set screws out!  Soaking in penetrant overnight and some very light heat with a micro torch. 

Damn pulley is still stuck tight to shaft.  

Can’t see how to use a puller, since the end of the step pulley is not open.  

Tom


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## Tozguy (Jan 26, 2019)

Huummm, too bad that it is so uncooperative!

Would tapping on the end of the pulley be worth a try?
Vibration might break the bond then maybe it could be worked back more easily.
As the man said, if it went on then it can come off. Sounds like a job for a puller of some kind. 



tcweb said:


> since the end of the step pulley is not open.



Drill and tap the end of the pulley for a draw bolt? Can we have some pics of the pulley?


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## tcweb (Jan 26, 2019)

I will send some pics.  I may try tapping it with a dead blow hammer, just to see if they key loosens up.


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## Mark Needham (Jan 26, 2019)

"dead blow hammer" be damned. Get an axe, and whop the muther.


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## tcweb (Jan 26, 2019)

Here are the pictures of the pulley.


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## hman (Jan 26, 2019)

Tozguy said:


> Drill and tap the end of the pulley for a draw bolt?


Couple years ago I had to remove the pulley from my (Grizzly RF-30 clone) mill motor.  I drilled and tapped the pulley, fashioned a suitably long draw bolt out of a piece of handy rod and two nuts.  IIRC, the drill depth was longer than my tap, so I had to counterbore in a short distance, to get the tap to thread to the end of the closed section of the pulley.  Note the two setscrews and the key on the bench next to the pulley.  Of course, once you've drilled through the closed section, you might want to shortcut the process by squirting in some Kroil or other penetrating lubricant.  Still a good idea to thread the hole ... for use of the draw screw some time in the future.


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## tcweb (Jan 26, 2019)

Got the pulley off!  Some low heat and some prying with a wooden dowel as a lever.

Evidence of a previous frustrated hammer mechanic was visible.   I have 1” of solid aluminum at the closed end of the pulley, so I put it on the lathe and drilled and tapped it for 5/16-18.   Hopefully next time I can remove the pulley much easier.


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## tcweb (Jan 26, 2019)

HMAN, I barely made it through with the taps I had.  I started with a regular starter tap, and switched to a plug tap.  Seemed to buy me the extra turn or two that I needed.

Should I be concerned about the crack at the end of the pulley?  (Wasn’t me - it was already there...)


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## tcweb (Jan 26, 2019)

I did pop the motor open and inspect the centrifugal switch.  It seemed fine, and the contacts look ok.


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## tcweb (Jan 27, 2019)

hman, does your motor have a plastic "fan" at the bottom, underneath the cover?    Wondering if that's even needed, I can't imagine it moves enough air to provide any cooling.   Mine is in rough shape - I'd replace it if I knew it does any good.

-Tom


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## Forty Niner (Jan 27, 2019)

tcweb said:


> Here are the pictures of the pulley.


Perhaps a puller setup with a slide hammer, since you don't have the end of the shaft to push against?


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## tcweb (Jan 27, 2019)

forty niner, that would probably work.  I have since removed the pulley, but I like that idea.  I could tap it futher ONTO the shaft, so clearly the light impact of a slide hammer would have probably worked to get it off as well.   Just finding a way to grab on to such a long part would have been the challenging part.


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## tcweb (Jan 27, 2019)

BTW, every darn nut and bolt on this Chinese motor is metric.  Just venting here...so frustrating to reach for a replacement screw/bolt, etc, and remember...metric.  I don't have a metric hardware stock.  Clearly that's something I should be looking to acquire.


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## tcweb (Jan 27, 2019)

One more question - for anyone with an RF30 or clone...

How to best mount the motor?  Do you first mount the swinging bracket and then bolt the motor to the bracket? Or bolt the motor to the bracket first, and mount the assembly?   Motor is damn heavy, at least for me.


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## hman (Jan 27, 2019)

tcweb said:


> HMAN, <snip> Should I be concerned about the crack at the end of the pulley?  (Wasn’t me - it was already there...)


I don't know.  I'd be worried if the crack happened in line with one of the set screws, or the keyway.  I suppose the crack will eventually propogate; not much can be done about it.  Maybe somebody else can offer an opinion.  Keep an eye on it in any case ... maybe mark how far it's gone, and check occasionally for spreading.



tcweb said:


> hman, does your motor have a plastic "fan" at the bottom, underneath the cover?    Wondering if that's even needed, I can't imagine it moves enough air to provide any cooling.   Mine is in rough shape - I'd replace it if I knew it does any good.


I never looked inside the motor.  Originally I just had to remove the spindle pulley, so I could modify the belt guard.  Added jack screws to it for future removal.  Removing the pulley and adding the jack screw was more or less an afterthought - do it while you can.  No idea of what's inside the motor, and I've since replaced it with a 3 phase (and VFD).  PS - I described the process of adding jack screws to the pulleys in an article that was published in the November/December 2017 issue of Home Shop Machinist.



tcweb said:


> One more question - for anyone with an RF30 or clone...
> How to best mount the motor?  Do you first mount the swinging bracket and then bolt the motor to the bracket? Or bolt the motor to the bracket first, and mount the assembly?   Motor is damn heavy, at least for me.


I cut a suitable length (~44") of 4x4 lumber, screwed plywood plates (10" round at one end, about 8" square at the other - but that's just what I had handy).  Set the post upright behind the mill and motor upright on the post.  Used the head crank on the mill to align the motor with the bracket.


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## tcweb (Jan 27, 2019)

Got the motor back on.  Wired it up.   Using the head crank to level the pulleys was a great idea.

Bad news:  with new Caps, there is NO difference!

Motor starts spinning, but won’t go up to speed.  Same as my original post to this thread.   Seems to pulse at few hundred RPM.

It’s too cold now.  Mabe later in the week, I will disconnect the belts to see if it’s related to the load on the motor.

Any other ideas?


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## markba633csi (Jan 28, 2019)

Fifteen amps is about the limit of most 110/120 volt outlets- are you sure you are getting enough voltage to the motor?  
Are you using a long and possibly thin extension cord?  
Did this starting problem just happen recently?  Or has it always started poorly?
mark


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## tcweb (Jan 28, 2019)

The problem has been happening since I've owned the mill.  I just set it up last fall, so I don't have a lot of history with it. The outlet is in the garage.  I have a 20A breaker feeding the garage, and it uses buried cable (3 wire, 12 gauge).  I technically have two 20A lines going out there, one is just for lights.   I'd estimate 50'-60' of buried cable. 

Maybe I'm nuts, but it seems to be happening more frequently now that it's cold.


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## markba633csi (Jan 28, 2019)

Hmmm does sound like the power is ok
There may be a bad winding in there- you say it does trip the breaker sometimes? That's a clue- the motor must have a fault since the power delivery seems adequate, even so, there is probably a sizeable voltage drop even with 12 ga wire
Running a motor of that horsepower on a 110 volt circuit is a losing proposition, the motor runs hotter, the switch contacts wear out sooner, larger gauge cables, etc. It may have been overheated before you got it.  My rule is 240 volt for anything larger than 3/4hp
So it sounds like you might could get 240 out there using the existing wire, but you may need a new motor anyhow


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## markba633csi (Jan 28, 2019)

If you have an analog multimeter (needle type) try and measure the voltage at the mill when you power it on. Use clip on test leads or something similar so you can watch the meter while you flip the switch- I think there's still a good chance your power delivery is the culprit here


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## Diecutter (Jan 28, 2019)

If it was me I would take another look at the centrifugal switch which connects the starting capacitor to the motor till its up to speed. Make sure you clean the contacts with a contact file or fine emery paper since appearance alone is deceiving. Also make sure the switch does not bind as it snaps on and off. Also, I would bring the motor inside , warm it up, and plug it into a dryer or stove 220v outlet to see if it spins up to full speed quickly; that would eliminate one possible problem right off the bat. Good luck.


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## tcweb (Jan 28, 2019)

When I pulled the cover off, I made sure the centrifugal switch was not bound up, and wasn't sticky.  There was a bit of surface rust, probably from years of humid environments, but overall, it looked OK.  The contacts looked very clean, again, nothing appeared to be sticking.

Can anyone comment on what happens to a motor when the centrifugal switch doesn't open?   I've read that it ban burn up a starter cap, which is why I've been cautious.  I did manage to trip the circuit breaker once by letting it "pulse" too long.  (haven't tried that since - don't want to damage the motor.


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## markba633csi (Jan 28, 2019)

Yes the cap and start winding can overheat if the centrifugal switch doesn't open.  The "pulsing" behavior could be either a motor fault OR there is still too much voltage drop in your supply line.
Diecutter: His motor is running on 120 volts- lotsa current and a fairly long run of wire, sounds like a possible voltage drop situation or his motor is bad


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## Diecutter (Jan 29, 2019)

markba633csi said:


> Yes the cap and start winding can overheat if the centrifugal switch doesn't open.  The "pulsing" behavior could be either a motor fault OR there is still too much voltage drop in your supply line.
> Diecutter: His motor is running on 120 volts- lotsa current and a fairly long run of wire, sounds like a possible voltage drop situation or his motor is bad


I agree. That's what I was trying to say (not very well) by suggesting he take the motor inside and hook it up near the main service panel at 120v, and also try 220v  which would eliminate the long wire run to the shop. Just a suggestion since I'm not well versed in motors.


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## tcweb (Jan 29, 2019)

Sounds like a reasonable thing to try.  It’s negative 10 here now, I may wait a few days...


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## Mark Needham (Jan 29, 2019)

Getting to the point, I think, where, instead of of everyone trying to guess how long the piece of string is, that you take the motor to a sparky, get him to check the bugger out. You, My Boy, are burning daylight, instead of making chips.
Of course this only seems to make sense when you have spent a dollar or 3 on a motor, that may or not be, completely buggered.
The more you spend on it, before you eventually do get a proper check out, is inversely proportional to the amount you will have saved.
edit. The centrifugal switch should operate also with the end bell on, ie, motor assembled. Honestly, just get it checked out by a bloke "Wot knows wot he's doing".


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## Mark Needham (Jan 29, 2019)

Diecutter said:


> I agree. That's what I was trying to say (not very well) by suggesting he take the motor inside and hook it up near the main service panel at 120v, and also try 220v  which would eliminate the long wire run to the shop. Just a suggestion since I'm not well versed in motors.


''Since I know bugger all about motors", why not hook it up to the dog, and if still no good, try the Electric fence.


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## markba633csi (Jan 29, 2019)

LOL hopefully not the dog


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## tcweb (Feb 16, 2019)

OK, so it got down to neg 24 (before the wind chill), but we are back into the positive temps.  I think it could hit 30 today.
I did some testing, and I'm starting to think this COULD be the damn centripetal switch after all.

I fired it up, and it did it's thing - speed up to (I'm guessing 1/4 speed), then bogged down and pulsed.
I turned it off.  No click.  turned it on and off 3-4 times - no click.   after 5-6 tries, it fired up.  Let it run for a few seconds.  Turned it off, and when motor slowed down, I heard the click of the springs pulling the centripetal switch back.

When I had it on the bench, I checked the assembly, and it seemed like it was moving smoothly.  I put a bit of penetrant on the springs, because there was some surface rust, but everything seemed OK.  No apparent sticking.

So what specifically should I look for when cleaning up that switch?   I've read cleaning contacts.  Just use an ignition file, and lightly smooth the contact surfaces?   

Tom


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## tcweb (Feb 16, 2019)

Mark Needham said:


> Getting to the point, I think, where, instead of of everyone trying to guess how long the piece of string is, that you take the motor to a sparky, get him to check the bugger out. You, My Boy, are burning daylight, instead of making chips.
> Of course this only seems to make sense when you have spent a dollar or 3 on a motor, that may or not be, completely buggered.
> The more you spend on it, before you eventually do get a proper check out, is inversely proportional to the amount you will have saved.
> edit. The centrifugal switch should operate also with the end bell on, ie, motor assembled. Honestly, just get it checked out by a bloke "Wot knows wot he's doing".



Mark, I agree, but honestly...not sure how many shops in the area still repair motors, let alone these Asian jobbers.  I'll do some calling.  Anyone have any ideas what it could cost to have a motor inspected/cleaned/balanced/tuned up?   Is it worth the cost?

-Tom


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## markba633csi (Feb 16, 2019)

Sounds to me like the start circuit is not closing properly when the motor comes to a stop.  This could be a problem with the contacts, the mechanism, or even a poor connection in the start circuit someplace.  You would need to do some detective work with an ohmmeter to find it, something that a good motor shop could do in a few minutes. Where are all the good motor shops these days? Unfortunately they seem to be a dying breed
Mark


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## Larry42 (Feb 16, 2019)

You may want to get a "*Bearing Separator and Puller Set.*"  If you use a regular two or 3 arm type puller it may break the pulley. Harbor Frt. has a set with two separators, about $50. No idea if it is any good but better than breaking the pulley. You can also buy the separators separately at industrial supply places but a lot more expensive. 

I would also check the internal switch. If the contacts look burned use an ignition file to clean them. Never use abrasives.


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