AboutWill Expertise Three phase electic motors, controls and related problems or failures, three phase motor installation issues, performance issues, connections, data and duty cycle information. All other electic motors. Specialty motors, repair concerns, performance concerns, obsolete motors and solutions. Other specialty equipment issues. Lost nameplate data and identification, lost connection data.
Also DC motors of all types.
See my profile under Home/electrical at this site
Experience 30 plus years in the electrical motor and apparatus repair industry. VP level management of repair facilities, current owner of my own specialty repair and consulting firm.
Organizations EASA, IBEW [retired], other specialty organizatons, Lubrication, Vibration EDI, Triboelectric Councils
Publications Currently fielding concerns at this site under "Home Electrical"
Education/Credentials 4 year technical, College level specific courses, EASA repair courses, vibration analysis electronic and electrical trade school.
Expert: Will Date: 6/12/2008 Subject: Air Compressor Motor
Question Hello. I have a Craftsman air compressor with a single phase, 3HP motor. The other day I went to the garage and started the compressor and left and when I went back the compressor wasn't running and there was a strong burning electrical smell. The compressor wasn't running but now it won't run at all. I checked the fuse to the motor and it's good. Could you tell me how I could check the motor to see if it has went bad? Thank you for your help.
Answer Well it is probably not good news, but a couple things, first is there a reset button on the motor anywhere? If not be careful sometimes they put an internal auto reset overload in the damn thing and if plugged in could come on with your hands in the belt on the shaft whatever,
BE CAREFUL FIRST
Next, any past history of trip off or anything going wrong with the motor, any noise, slow starting, anything else? Any severe weather withing the last week or a power failure of any kind you are aware of?
We need to find out first if the motor is bad and second why, if the motor failed it could be due to natural causes but you would like to know so you are not buying motors every week for this.
First, make sure the breaker is not tripped, or bad, manually trip and reset it, let me know,
Next, if nothing happen, get a volt meter or electician if you are not up to this and make sure that voltage is coming from the breaker.
If not bad breaker maybe but let me know,
If there is voltage shut it off [breaker], take the belt off the motor, so no accidents, with an ohm meter check to see if there is an ohm value where the wires connect to the motor when the breaker is off and open, if nothing shows up and it will be a low reading, but readable the circuit in the motor is open, go to the caps next, same test,
Take the ohm meter and put one lead on a bare screw in the frame, and one lead on one of the incoming power posts of the motor, if there is a reading the motor is grounded, get it fixed or a new one,
A motor can short and still be above ground so it is not a full proof test, all you can check is that there is power, if so, are the windings open, then the caps, and past that not much else to look at,
You can take some dry compressed air and blow in the openings of the motor while rotating the shaft by hand sometimes dust gets in the start switch and that happens often, but the burn smell is a bad sign, even if not now, the motor is probably weakened,
above all be Careful!!!!!!!!!!!!!!!!!!!!!!! The motor could restart on its own when cooled and show no grounds, so do all this with breaker off!!!!!!!!!!!!!!!!!!!!!!!!
