# Motor Winding Test



## DriveGuru (Jul 29, 2012)

Switch is N.C. , switch 5 & 8 to reverse direction


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## Bootss (Dec 30, 2011)

dronai said:


> I need to test the start winding on a single phase motor there's no drawing. if I remove the capacitor can I test from one of those leads to common ? or just to both ends of where the cap was ? Ugly's shows the wires as T5 & T 8
> 
> Also, it probably has a centrifugal switch,
> 
> this should be N/C correct ?


the centrifical switch is closed when the motor is off or not running and then opens when it comes up to speed.

check the capacitor. then if the motor doesn't start most likely start winding bad. quick bench test is if you have to spin the shaft to start the motor the start winding is shot,also if its burnt it will smell bad


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## dronai (Apr 11, 2011)

Got the drawing online


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## dronai (Apr 11, 2011)

Lep said:


> the centrifical switch is closed when the motor is off or not running and then opens when it comes up to speed.
> 
> check the capacitor. then if the motor doesn't start most likely start winding bad. quick bench test is if you have to spin the shaft to start the motor the start winding is shot,also if its burnt it will smell bad


This is in a machine and it is not easily removable. No smell, the cap measured wrong, but I don't trust my meter  The motor hums which is a good sign indicating just the cap. Just want to test the start winding for continuity. Hooked to a gear reducer so I can't spin it. looks like T5 and T8 should have continuity


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## 8V71 (Dec 23, 2011)

Did you mean T6 and T8? Motor humming could still mean the start winding is toast....or not.


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## dronai (Apr 11, 2011)

8V71 said:


> Did you mean T6 and T8? Motor humming could still mean the start winding is toast....or not.


Yes ! Looks like T6 goes through the centrifugal switch, and becomes T5

Humming and no rotation could till mean there is no start winding. I can't get access to check the winding now, and the customer went to get a replacement cap. Thing was trying to start with low voltage, so hopefully only the cap is bad.


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## 8V71 (Dec 23, 2011)

dronai said:


> Yes ! Looks like T6 goes through the capacitor, and becomes T5


fify


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## dronai (Apr 11, 2011)

8V71 said:


> fify


Look at the drawing again, T5 through the Cap and becomes T6, then through the switch, and becomes T5 again, after the coil it becomes T8

So your right test between T6, and T8


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## Bootss (Dec 30, 2011)

What kind of machine is this motor on/in?
it's possible the internal switch could be bad usually they don't go bad but they do


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## 8V71 (Dec 23, 2011)

dronai said:


> Look at the drawing again, T5 through the Cap and becomes T6, then through the switch, and becomes T5 again, after the coil it becomes T8
> 
> So your right test between T6, and T8


Gotcha...you will have access to the T6 wire.


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## Bootss (Dec 30, 2011)

if you have to get it rewound get the internal switch changed also since its such a headache to get in the machine


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## dronai (Apr 11, 2011)

Lep said:


> What kind of machine is this motor on/in?
> it's possible the internal switch could be bad usually they don't go bad but they do


A crusher. No I think it's too new for the switch to fail.

Rewind is not worth it on a 3 hp


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## Ultrafault (Dec 16, 2012)

I have seen a lot of bad start switches make sure you check that.


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## Bootss (Dec 30, 2011)

Ultrafault said:


> I have seen a lot of bad start switches make sure you check that.


if there's rock dust getting into the stator it could easily be the internal switch,hopefully its a TEFC motor


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## Ultrafault (Dec 16, 2012)

A 3 hp rock crusher? I was thinking corn.


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## Ultrafault (Dec 16, 2012)

Usually the farmer fills them so full of grease it fouls the switch.


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## dronai (Apr 11, 2011)

Lep said:


> if there's rock dust getting into the stator it could easily be the internal switch,hopefully its a TEFC motor





Ultrafault said:


> A 3 hp rock crusher? I was thinking corn.


 This crushes electronic boards


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## Bootss (Dec 30, 2011)

dronai said:


> This crushes electronic boards


well you still want to have a TEFC motor because that dust is an insulator and if it gets between those contacts on that internal switch guess what


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## Bootss (Dec 30, 2011)

I'm sure you'll have fun figuring this project out and make money
:laughing::laughing:


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## dronai (Apr 11, 2011)

Lep said:


> well you still want to have a TEFC motor because that dust is an insulator and if it gets between those contacts on that internal switch guess what



Lep, look at the symbol in the drawing I'm thinking is the switch. That could be another type of switch. It doesn't look like a pot relay, what else do they use on single phase ?


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## dronai (Apr 11, 2011)

Ultrafault said:


> Usually the farmer fills them so full of grease it fouls the switch.


How can you get to those switches ? access point ?


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## Cow (Jan 16, 2008)

dronai said:


> How can you get to those switches ? access point ?


Keep asking questions, I'm learning right here with you. All my work is 3 phase, I have to look at the diagram to wire a single phase motor. Let alone troubleshoot one...


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## 8V71 (Dec 23, 2011)

dronai said:


> How can you get to those switches ? access point ?


By removing the rear housing. That square thing in the drawing is the switch.


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## dronai (Apr 11, 2011)

Cow said:


> Keep asking questions, I'm learning right here with you. All my work is 3 phase, I have to look at the diagram to wire a single phase motor. Let alone troubleshoot one...


 Just tell them to get a new $800 motor and find out it was just the switch or the cap :laughing:


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## 8V71 (Dec 23, 2011)




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## dronai (Apr 11, 2011)

8V71 said:


>


 
That would be a bear to get to on this motor. I have to disassemble the machine to get the motor out.


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## 8V71 (Dec 23, 2011)

From your description of running on very low voltage the switch would be the last thing I would suspect.


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## dronai (Apr 11, 2011)

8V71 said:


> From your description of running on very low voltage the switch would be the last thing I would suspect.


 Me too, but good to know


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## Bootss (Dec 30, 2011)

do you know what speed the motor is perhaps 1800 or is it 3600? if that's a special frame the motor or if the laminations are pressed into the machine with special configuration or something then it will be worth winding


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## dronai (Apr 11, 2011)

Lep said:


> do you know what speed the motor is perhaps 1800 or is it 3600? if that's a special frame the motor or if the laminations are pressed into the machine with special configuration or something then it will be worth winding


There is a number in HP where it's not worth it rewinding, and this fits that HP


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## wendon (Sep 27, 2010)

You're kinda stuck if you can't get at the motor. Could be a number of things. Open winding, bad start switch, bad rotating mechanism, bad capacitor etc. Did you check it for a short to frame? By the drawing it doesn't look like it has a run capacitor. If the capacitor doesn't fix it you could try the hammer method. Tap on the motor end bell opposite of the shaft extension. Sometimes that will jar a stuck rotating mech loose. Do an amp check on #8 when it's trying to start. Have you checked out the main windings? I take it you're sure the motor can actually spin and it isn't a case of locked rotor? High voltage or low voltage connection?


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## Bootss (Dec 30, 2011)

dronai said:


> There is a number in HP where it's not worth it rewinding, and this fits that HP


I wonder what a new one cost?
some small shops may rewind that motor,like if someone gave the small shop a free one or something


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## dronai (Apr 11, 2011)

wendon said:


> You're kinda stuck if you can't get at the motor. Could be a number of things. Open winding, bad start switch, bad rotating mechanism, bad capacitor etc. Did you check it for a short to frame? By the drawing it doesn't look like it has a run capacitor. If the capacitor doesn't fix it you could try the hammer method. Tap on the motor end bell opposite of the shaft extension. Sometimes that will jar a stuck rotating mech loose. Do an amp check on #8 when it's trying to start. Have you checked out the main windings? I take it you're sure the motor can actually spin and it isn't a case of locked rotor? High voltage or low voltage connection?


 I can get at the pecker head/cap by removing the control panel in front. High voltage connection. No shorts


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## dronai (Apr 11, 2011)

Lep said:


> I wonder what a new one cost?
> some small shops may rewind that motor,like if someone gave the small shop a free one or something


 About $800


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## Bootss (Dec 30, 2011)

did a new capacitor fix it?


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## dronai (Apr 11, 2011)

Wont know until tomorrow


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## John Valdes (May 17, 2007)

http://www.goevans.com/EHB_pgs0803.pdf


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## dronai (Apr 11, 2011)

Life is good brother


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## dronai (Apr 11, 2011)

Fixed !!! Just the Cap


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