Problem with compressor motor

[ironroad 9c1]

About a month ago I turned on my compressor, and the motor kinda surged up and down a couple of times, and before I could click it off I heard a pop and it stopped , never to move again since, I seen it has what looks like a capacitor on the outside, Anyone think maybe thats bad?

 

[goodfellow]

About a month ago I turned on my compressor, and the motor kinda surged up and down a couple of times, and before I could click it off I heard a pop and it stopped , never to move again since, I seen it has what looks like a capacitor on the outside, Anyone think maybe thats bad?

Yes it could be -- take off the cover and see/smell if there is a problem.

This thread discussed very much the same thing

http://www.garagejournal.com/forum/showthread.php?t=28424&highlight=capacitor+tester

Good luck!

 

[rinny_tin_tin]

About a month ago I turned on my compressor, and the motor kinda surged up and down a couple of times, and before I could click it off I heard a pop and it stopped , never to move again since, I seen it has what looks like a capacitor on the outside, Anyone think maybe thats bad?

Shut off the power and carefully remove the capacitor - noting lug/lead locations. Short the capacitor lugs with a screwdriver. Get an analog ohm-meter (e.g., Simpson) set on Ohms x1000. Alternate your probes across the leads - if the capacitor is good the meter pointer should kick up to 0 ohms and slowly decay down to infinity. What is peculiar is the motor surging you describe.......

Let us know what you learned

 

[ironroad 9c1]

well no smell, but I did notice the capacitor has a sticker that says 120v and the lugs are soldered , my compressor is 220-240 and what is the need for a "starter box? I just have mine wired into the breaker panel and just use the breaker to turn it on and off...guess thats a bad practice?

 

[rinny_tin_tin]

well no smell, but I did notice the capacitor has a sticker that says 120v and the lugs are soldered , my compressor is 220-240 and what is the need for a "starter box? I just have mine wired into the breaker panel and just use the breaker to turn it on and off...guess thats a bad practice?

Not necessarily - you can use a breaker for on/off up to some # hp (I forget - but I'm sure someone here will remember). Check the cap - cut the wires to disconnect and then resolder if they are fine (NOTE connections). The cap should say what its working voltage is and it better be more than 240VAC

 

[ironroad 9c1]

well judging by the replacement motors with the same size 1 1/8 inch output shaft, I figure its around 5 hp.

 

[Aceman]

what is the need for a "starter box? I just have mine wired into the breaker panel and just use the breaker to turn it on and off...guess thats a bad practice?

I definitely wouldn't call it good design. I'm sure the breaker will not last as long being cycled constantly in addition to the arcing from starting the motor, which a motor starter is designed for. Plus, starters provide overload protection if your motor doesn't have it built in.

Personally, I would pull the belt first and then try to start the motor. It's not uncommon, but people call us and tell us their breaker is tripping and that they have a motor problem. We show up and ask them, "did you pull the gearbox off or remove the belt before assuming the motor was bad?" "Uhhhh.....no."

Simple things first.

 

[ironroad 9c1]

well i can turn the shaft, it snot locked up , it just doesn't do anything, It does have a breaker on the side of the motor, but it doesn't seem popped and i have voltage on any connector on the backside. but I only have about 120 going to the capacitor

 

[Charles (in GA)]

Not necessarily - you can use a breaker for on/off up to some # hp (I forget - but I'm sure someone here will remember).

Some single pole breakers are approved as switches for induction lighting, but I do not know of any approved as switching for motors or anything else.

From a Siemens FAQ page....................

Q: What breakers are rated for HID lighting at 480V?

A: HID stands for High Intensity Discharge and applies to several types of high output lighting such as high pressure sodium and mercury vapor. This type of lighting is particularly difficult for circuit breakers to switch and requires special testing of the breaker. Only the Siemens BQD 1 Pole 15-30 amp circuit breakers are HID rated at 480Vac.

Q: What does the SWD rating mean?

A: It means "Switching Duty". This rating applies to the switching of fluorescent lights ONLY, not HID lights or any other types of loads. The rating is limited by UL to 15-20A, 1 Pole circuit breakers. See the footnotes in the Siemens 2004 SPEEDFAXTM. At 480V, only the Siemens BQD and Siemens Sentron™ ED breakers are SWD rated.

Not the answer, but good information.

Charles

 

[rinny_tin_tin]

Some single pole breakers are approved as switches for induction lighting, but I do not know of any approved as switching for motors or anything else.

From a Siemens FAQ page....................

Q: What breakers are rated for HID lighting at 480V?

A: HID stands for High Intensity Discharge and applies to several types of high output lighting such as high pressure sodium and mercury vapor. This type of lighting is particularly difficult for circuit breakers to switch and requires special testing of the breaker. Only the Siemens BQD 1 Pole 15-30 amp circuit breakers are HID rated at 480Vac.

Q: What does the SWD rating mean?

A: It means "Switching Duty". This rating applies to the switching of fluorescent lights ONLY, not HID lights or any other types of loads. The rating is limited by UL to 15-20A, 1 Pole circuit breakers. See the footnotes in the Siemens 2004 SPEEDFAXTM. At 480V, only the Siemens BQD and Siemens Sentron™ ED breakers are SWD rated.

Not the answer, but good information.

Charles

I can't get to any of my NECs right now as they are packed up - but I recall that they allow a ckt brkr as an on/off up to some hp - maybe it was up to 2 or something like that or maybe for any of the motors with integral thermal trips. But iaw UL 439, the interrupting and short ckt rating of breakers feeding corresponding motors exceed the same for corresponding motor contactors - so unless there is a soft start, heaters, shunt trip/remote, etc there is nothing gained from a specific motor controller for a 5 hp motor.

However, we are getting far afield here - I see where he states that the comp is 240, yet the capacitor case says 120? What gives?

Did he lose a leg ? Does he have 240 there or what?

 

[rinny_tin_tin]

well no smell, but I did notice the capacitor has a sticker that says 120v and the lugs are soldered , my compressor is 220-240 and what is the need for a "starter box? I just have mine wired into the breaker panel and just use the breaker to turn it on and off...guess thats a bad practice?

For a 5 hp motor, your voltage has to be at least 240 - so do you have 240 going to it or 120? Maybe you lost a leg? Dig out yer meter and measure across the line - you better have 240

 

[ironroad 9c1]

yea i got 240 up to the motor, but like i said , only 120 at the capacitor....it was working fine for 3 1/2 years now.

 

[35mastr]

That size shaft sounds like a 184T Frame.

If you decide to get a new motor try to get the right frame number off the tag.Or your going to play hell trying to mount it.

 

[rinny_tin_tin]

That size shaft sounds like a 184T Frame.

If you decide to get a new motor try to get the right frame number off the tag.Or your going to play hell trying to mount it.

SOunds like a separate start/run sys - split phase, etc. How many terminals on cap? Is cap good or bad?

 

[35mastr]

The motor sounds like its single phasing.Most likely you lost one of the legs.

Might as well just pick up a good brand name motor if the compresor is worth it.

 

[35mastr]

SOunds like a separate start/run sys - split phase, etc. How many terminals on cap? Is cap good or bad?

I am not understanding you question.

All motors have a frame number that usually corisponds to the shaft size and mounting surfaces.

On that tag it will also have the HP,RPM,Spec1,Phase,Etc.

That is important when looking for a replacement to fit direct.

 

[ironroad 9c1]

no id tag on it...but i figure its worth fixing, you don't find many real 2 stage v type compressors anymore, most new box store **** is single stage 2 cyl types .

 

[rinny_tin_tin]

I am not understanding you question.

All motors have a frame number that usually corisponds to the shaft size and mounting surfaces.

On that tag it will also have the HP,RPM,Spec1,Phase,Etc.

That is important when looking for a replacement to fit direct.

Aye - all that is true, but nameplate won't tell you anytin about capacitor or wiring

 

[rinny_tin_tin]

The motor sounds like its single phasing.Most likely you lost one of the legs.

Might as well just pick up a good brand name motor if the compresor is worth it.

It is single phase - and he said hes got 250 - so no lost *leg*

 

[goodfellow]

Just for laughs, just hook up an analog ohm meter to the cap terminal and test it -- as was mentioned previoisly in this thread. If it checks out, then the motor itself is suspect. Repairing a motor for this application is probably not worth it --

 

[rinny_tin_tin]

no id tag on it...but i figure its worth fixing, you don't find many real 2 stage v type compressors anymore, most new box store **** is single stage 2 cyl types .

No wonder you didn't post the pic earlier - tis one sorry lookin sob - they would have told ya to kill it

 

[ironroad 9c1]

lol that was when I first got it, traded a shotgun for it, This is it nowadays. with a little paint and I replumbed the outlet.

old like my truck..lol

 

[rinny_tin_tin]

wow - you really pimped dat thing up - what are the skis for? do you straddle that thing and ride it downhill in the snow al la slim pickens


Good work. Like the jeep!

Check the cap!

 

[Charles (in GA)]

I hope the shotgun you traded off wasn't any good

You stated in an earlier post that the motor.... It does have a breaker on the side of the motor, but it doesn't seem popped

I'm curious about this. Some motors have a thermal overload button on them, usually in the end opposite the shaft. I don't see anything here..... you said it had a "breaker" on the side, can you show a pic or elaborate?

A five horse motor is unusually large for an internal thermal overload.

Charles

 

[ironroad 9c1]

back

Front

can't push the button in or pull it out. and i've had this thing for 3 1/2 -4 years so it its dead i got my trades worth.

 

[Mr_fixit]

I hope the shotgun you traded off wasn't any good

You stated in an earlier post that the motor.... It does have a breaker on the side of the motor, but it doesn't seem popped

I'm curious about this. Some motors have a thermal overload button on them, usually in the end opposite the shaft. I don't see anything here..... you said it had a "breaker" on the side, can you show a pic or elaborate?

A five horse motor is unusually large for an internal thermal overload.

Charles

Farm duty motors usually have overload protection built in.. Most up to 7.5hp..

 

[Charles (in GA)]

Thats an old Klixon breaker. I don't understand the three wires that appear to be on it (is that what I'm seeing?) but no, they don't pull. Could have failed internally. Have you checked for continuity thru it?

Charles

 

[ironroad 9c1]

yea , I get reading through 2 out of 3 and if you check two other terminals you get noting.
hard to explain with 3 terminals..lol the way its wired, is one leg from the incoming wire from the pressure switch, one leg to to inside of the motor and then another leg directly to the inside of the motor with no wire nut. and then the other leg of the pressure switch is wired to the inside of the motor.