# capacitor on motor smashed!!



## pjf134 (Apr 7, 2011)

Someone gave me a 1 HP motor with a cap hanging on by 2 wires, been like that for years, no problem until I put it on my lathe. I made my shim for the 1/2 HP motor and noticed the motor on the countershaft smashed it when I adjusted the tension bar I guess. It still runs good after I pieced it together for now. I did make a holder for it (TOO LATE I GUESS), BUT WOULD LIKE TO GET IT RIGHT. Where would I find numbers on it? Maybe just glue the plastic back together and put the holder on. It maybe has a different cap on it than original, just don't know, since I got it that way. It's a 1 HP , 1725 RPM, duel voltage single phase. It's still on the lathe for now, I am wiring the 1/2 HP motor and switch and plan on doing the switch soon, just trying to figure out where to mount my switch.
 Paul


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## Tony Wells (Apr 7, 2011)

If it is a metal cased capacitor, the value will be stamped or embossed on the shell. If it is a bakelite cased capacitor, the markings are usually ink stamped on the outside. mark any wires you remove and note any markings, like number, letters, or symbols like triangles, squares or circles near the terminals.


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## pjf134 (Apr 7, 2011)

Tony,
 Thanks, I will check tomorrow, it is bakelite, just not sure if it is original though.
 Paul


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## Tony Wells (Apr 7, 2011)

If it has been running ok, the values were probably fine, original or not. Look for XXX mfd for the value, and XXX volts for the rating. Could be up to 450 volt, guessing 125 mfd. Best to get exactly what was there, value and ratings. Ratings can be safely raised, but not so much on the value. Don't go below the voltage rating.


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## pjf134 (Apr 7, 2011)

Tony,
 I can only get some numbers from the cap, printing is wore off, see pic. C70-30 Start cap- 26225---
 Paul


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## Zigeuner (Apr 8, 2011)

[quote author=pjf134 link=topic=1587.msg9237#msg9237 date=1302152128]
 Someone gave me a 1 HP motor with a cap hanging on by 2 wires, been like that for years, no problem until I put it on my lathe. I made my shim for the 1/2 HP motor and noticed the motor on the countershaft smashed it when I adjusted the tension bar I guess. It still runs good after I pieced it together for now. I did make a holder for it (TOO LATE I GUESS), BUT WOULD LIKE TO GET IT RIGHT. Where would I find numbers on it? Maybe just glue the plastic back together and put the holder on. It maybe has a different cap on it than original, just don't know, since I got it that way. It's a 1 HP , 1725 RPM, duel voltage single phase. It's still on the lathe for now, I am wiring the 1/2 HP motor and switch and plan on doing the switch soon, just trying to figure out where to mount my switch.
 Paul
[/quote]

Here is a simple home test for approximate capacitance values using a light bulb and an AC voltmerer. 

http://toad.net/~jsmeenen/capacitor.html

By the look of your capacitor, it's probably a Packard brand. They have flooded the market in the past ten years. Made in China, of course, but perfectly good. I would guess that you could use a 100-150 Âµf start cap at 250 volts for a 1 hp motor, assuming it will fit. 


Happy Trails.


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## Starlight Tools (Apr 8, 2011)

[quote author=pjf134 link=topic=1587.msg9276#msg9276 date=1302202903]
Tony,
 I can only get some numbers from the cap, printing is wore off, see pic. C70-30 Start cap- 26225---
 Paul
[/quote]

Paul 

Looks like a 70 - 80 uF Starting Cap. 

Most common for a replacement would be 72-88 uF. 125V should be ok, but if you err to 250V will not hurt. Any motor repair shop like myself and many others will have these in stock, I know I do.

If you have other caps floating around, you could try one. Too low and the motor will not start. Anything over that value and it just excess, that does not do anything, but preferably you should be within +/- 10% of the rated value.

Walter


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## Tony Wells (Apr 8, 2011)

I'll concur with Walter. 72-88 mfd @125 volts would be a good candidate, although I'd probably go 250 or even 370 on the voltage rating. Pretty common. Motor shops everywhere should have them, and here we even have a You Fix It show that caters to the DIYer, and they sell motor caps all the time.


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## Zigeuner (Apr 8, 2011)

I must have missed that he is operating this motor on 120VAC.


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## Tony Wells (Apr 8, 2011)

No Zig, he never said. That is an important consideration, and one reason I recommended a 250 or 370 volt cap.


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## Zigeuner (Apr 8, 2011)

[quote author=Tony Wells link=topic=1587.msg9429#msg9429 date=1302314790]
No Zig, he never said. That is an important consideration, and one reason I recommended a 250 or 370 volt cap.
[/quote]

Extra capacitance and voltage rating is not harmful so long as the physical size is acceptable. My RPC needed 500 + Âµf to start a 5 hp three-phase motor. I use about 100 Âµf per hp as a general rule but if he's running on 120VAC, probably 75-80 Âµf would be OK.


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## Starlight Tools (Apr 8, 2011)

The start winding on that motor is only 120 volts, it will be in parallel with one of the run windings on 220V and both of them on 120V so the Cap will be fine being a 120 V one. There are very few of those motors that need the 250V cap.

Walter
The Motor Doctor.


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## Tony Wells (Apr 8, 2011)

True, Walter. I guess I was thinking about an A/C condensing unit I worked on last month. Cap there was 370 V.


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## Starlight Tools (Apr 9, 2011)

Tony

I use 250V caps when I want a bit more start time. Usually the larger voltage capacity will give a hard start motor a bit of grace, but not much, in the start windings.

those 370V caps were probably run caps, not start ones. they are generally higher value.

Walter


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## Tony Wells (Apr 9, 2011)

Walter, correct me if I am wrong, but I am thinking that the value of the cap rather than the operating or rated voltage determines the start coil time. It's a function of charge time. The voltage rating is determined by the dielectric material and strength, and the terminal spacing, etc. I can't see how that changes the charge time.

Of course, I'm leaning back on general electronics knowledge, not specific to motor caps.

And, perhaps you're right on the run cap. I just checked for ESR, leakage, and value. All was good, so I buckled it back up. Just spring prep for the shop air system.


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## Starlight Tools (Apr 9, 2011)

Tony

The higher voltage rating means the dielectric is a bit stronger and takes more to punch it with a voltage spike as it overheats.

When we have a submersible water pump that goes through capacitors too often, we will up the voltage and often that stops the mayhem. It takes a lot of energy to get a pump going when it has a head of water on it.

Upping the voltage will not change the start time, it will only protect the Cap for a few more milliseconds against blowing up when we are in a hard start situation where the motor takes longer to get up to speed. Overall this is not recommended as everything is being taxed by a slow starting motor, not just the cap.

Fan and AC motors, are very commonly Capacitor Run motors. It is amazing how much energy is required to move air! On these motors the start circuit is never removed from the circuit. Here the Capacitance is low, often only a few uF, somewhere often between 5 to 25. As the capacitance decreases, the motor has a hard time starting, but as the capacitance increases, the running current rises. Even a few uF can change the current.  These capacitors are often all metal cans, but can also be sealed plastic as well.

Walter


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## Tony Wells (Apr 9, 2011)

OK, pretty much same thing, just different words. The additional voltage rating "beefs up" the cap allowing a little more abuse before failure (punch through the dielectric). Agreed. I thought I was reading that you gained start time by using a higher voltage rating cap. Gain is in life of the cap time. Agreed.

I was talking about the cap for the compressor, so I believe it is a start cap. Last year, I had one fail, open, and of course, no start. I have also seen one that simply drops it's value and will not start consistently. An A/C buddy sometimes parallels another cap to the "weak" one to get by in a pinch. That should only be until a proper cap is available.


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## ChuckB (Apr 9, 2011)

I am using the same Westinghouse motor as you. The cap it uses is a Dayton P/N: 4X066 available at Grainger. (324-388 MFD @ 110-125VDC) You are using 110VAC, right?

Some of the automatic doors I use to work on had AC motors that used starting capacitors.. on a couple of occasions, I would get to the job to find the motor humming and the thermal overload kicking on and off..motor red hot.. a capacitor failure.. not having one in the truck, I would pry the lock ring off the top of the capacitor.. slide the main body out..unroll it..find where it shorted.. tear a piece of mylar from the end.. slightly shorten the length of the plates.. patch the shorted area of the plates.. oil the body.. slide it back in..got me by until I could get back with a new part..


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## Tony Wells (Apr 9, 2011)

Hahaha! Great, Chuck! Not many people would trouble themselves even to attempt that.


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## pjf134 (Apr 9, 2011)

Chuckb,
 That 1 HP motor came off my big fan, the only problem was the motor only went cw and I needed ccw, so what I did was figure 8 the belt so it went the right way. I did check years ago on the net and the motor was not reverseable, maybe it's time to check again. The fan was a 1 1/2 HP 3 phase that came on it, but no setup in shop for it yet. I only put the motor on my lathe to check it out, but now since I got the pulley on my 1/2 HP fixed I will take it off and use the 1 HP for the big fan again. If you have the same motor, can it go ccw? If you need more info I can take a pic of it.
 Thanks,
  Paul


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## ChuckB (Apr 9, 2011)

Here is the plate that was on mine:




This is a rough drawing I made (not 100% technically correct, but it worked for me..) and I was able to reverse the direction. Not too hard to do if you have an OHM meter:


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## Starlight Tools (Apr 9, 2011)

Paul

It is going to depend on how many of the leads were brough out to the wiring junction box as to whether you can revese the motor or not. 

IF the motor was wired in such a way that it was considered non reversible, that means that some of the wires are wired directly to the motor windings. These motors are reversible at a cost, they require surgery to open up the crown and draw out the extra wires. I did this for Baldor when they had mis-ordered a bathc of motors for a compressor plant. The motors were all rotating the wrong way, so I was contracted to switch them all around.

A conventional reversible motor will have between four and six leads in the junction box, depending on Voltage.

110 Volt only motor, four leads
110/220 Volt motor six leads

each set of leads is 110 Volts. Two sets will be run windings, and the other set will be the start winding.

We will deal with the dual voltage reversible motor here.

to wire the motor for 110V, all three sets of leads will be wired in parallel.
to wire the motor for 220V the two run windings will be in series and the start winding will be in parallel to ONE of the run windings.

To reverse the rotation, interchange the two start windings leads, usually tagged as 5 and 8 or in ChuckB's case as red and yellow.


A three phase motor is reversibel even easier, just swap any two power lines and presto chango, it now turns the other way.

If you have any further questions, post some more pictures and we will attempt to get you so confused your head will never stop spinning, LOL OK so may we will just try to get the fan spinning and not the head.

Walter


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## ChuckB (Apr 9, 2011)

Yes, if you can find the start winding, identified as the winding that has the cap and the centrifigal switch in series then by reversing it, it will change the direction of the motor. Very easy to do with an ohm meter as long as it is already isolated. Otherwise you will have to cut some wires to even identify the starter circuit.. kind of a guessing game.


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## pjf134 (Apr 9, 2011)

This is the 1 HP motor details. Westinghouse 312p189, type A, H56, 1-HP, 1725, 60 CYC, 115/230, AMP 14.6/7.3, I PH, CODE L. See scan and pic. I hope this can help for setting up to reverse motor.
 Thanks,
 Paul


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## ChuckB (Apr 9, 2011)

Wow.. I don't think I can be much help with that, unless I was your next door neighbor.. 

Are you electrically inclined and good with a meter?

It looks as though your start winding is isolated, but it's a matter of finding it.. I was in a similiar situation with my motor. Some colors had faded, so I had to take my motor apart and trace it with an ohm meter, thus the basic drawing that I posted. The one wire with the question mark in my drawing was not used.. apparently someone added it to monitor the full motor speed (when the centrifigal switch kicked out.) I'm glad I opened mine up though, all the wiring was cracked and I repaired it with new wiring and heat shrink.


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## ChuckB (Apr 9, 2011)

[quote author=Tony Wells link=topic=1587.msg9480#msg9480 date=1302365600]
Hahaha! Great, Chuck! Not many people would trouble themselves even to attempt that.
[/quote]

I was just trying to get the customers door back in service and keep my boss happy. It was also fun showing off to the in house maintenance crew as to what I could do in a pinch.


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## pjf134 (Apr 9, 2011)

Chuck,
 I do have meters and have done some electric work, mainly working with one of my friends who does that type of work. I used to do scoreboards with him when he needed an extra hand, also other types of electric. He is working 16 hour days now,so he is not my go to guy right now. I can use a meter if you just tell me in layman terms what to hook too, such as ohm reading from L1 to L2 ect. I really have not messed with motors that much so do not know the lingo.
 Thanks,
 Paul


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## ChuckB (Apr 9, 2011)

Paul, Here goes..I will try to explain this the best I can.. I am no engineer, but am quite good at figuring some things out. I include this as one of those things. This is exactly what I did, and it worked for me. Anyone that wants to explain it better, feel free to do so.. ;D

Look at my basic circuit. You will observe that it is really two circuits in one. One to the left of "A" and "B" and one to the right of "A" and "B". If you can't comprehend this, stop now and get help. 




The run circuit has more windings than shown in my drawing, but when isolating the run windings for the start winding, lets keep things simple and treat the run circuit as one winding. Getting more involved with the run windings will occur if you are changing to 220 volts, which will not affect the start winding.

The first thing I would do is mark all the wires using a wire marker kit or some other means.Get your camera out and take many close up pictures too. They will help if you get in trouble. I would remove all the wiring from in front of the terminal plate.  If it's within your capabilities, I would remove the motor housing cover,(If removing this housing is not within your capabilities, stop and get some help.) Make sure to unscrew the centrifugal switch first, then the long screws with nuts come out. Although somtimes, difficult, the housing will come off with a little coaxing. Make sure you don't lose any of the bearing shims. also remove the two screws in the back of the terminal plate. You now can then get to the centrifugal switch that connects to the capacitor and looking at my diagram be able to isolate the start winding.. again, the start winding will be the one that has the capacitor and the centrifugal switch in series with it.. This circuit should be seperate and have no relation to the wires on the back of the terminal plate.There are probably four wires in the rear of the plate and these are the run windings. (see picture below of the multi colored wires connected to the back of the terminal plate.) 
	

		
			
		

		
	




In some instances, as Walter mentioned the start winding wires will be connected directly to the run winding wires and will have to be isolated. When you are done you will end up with four wires, which are the two above mentioned circuits. By reversing the two start winding wires, the motor will reverse.

When putting the motor housing back on, make sure no wires are rubbing and also make sure the motor spins freely..as freely as it did before you took it apart.  

Now you can try and get lucky by not taking the motor apart and just guessing, but this is how I recommend to do it.. It's your choice. 

This is the best way I can explain this without having your motor in front of me.. probably the hard way, but it is the sure way.. 

Again, this is the exact way I figured mine out. I hope this helps a little. Maybe others can chime in for some additional support. 


EDIT------------------------------------------------------

I might add that the capacitor, centrifugal switch and start winding doesn't necessarily have to be in the order of my drawing to work. As long as they are in series. I have saw different variations.


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## Starlight Tools (Apr 10, 2011)

Paul

your motor is dual voltage so you will have two run windings in parallel to each other when wired 110V, not just one as shown in ChuckB's diagram

Walter


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## ChuckB (Apr 10, 2011)

[quote author=starlight_tools link=topic=1587.msg9554#msg9554 date=1302415044]
Paul

your motor is dual voltage so you will have two run windings in parallel to each other when wired 110V, not just one as shown in ChuckB's diagram

Walter
[/quote]

Walter re-read my post.. I covered that point:

"The run circuit has more windings than shown in my drawing, but when isolating the run windings from the start winding, lets keep things simple and treat the run circuit as one winding. Getting more involved with the run windings will occur if you are changing to 220 volts, which will not affect the start winding."

He is asking how to reverse his motor by finding and isolating the start windings, not how to change the motor to 220.. I would think that he wouldn't have to touch the run windings.

Let's don't make this more confusing than it has to be for him..


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## ChuckB (Apr 10, 2011)

Paul, Here's another diagram much like my drawing, but neater


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## pjf134 (Apr 10, 2011)

Thanks Chuck &amp; Walt,
 I am keeping the motor on the lathe for now, since I have to make a bracket for my drum switch for mounting and some other things before I can use my other motor. I will tear into it when it comes off.
 Paul


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