Over heated motor

I realize I'm off the path of PLC's, but I need the help.

I have an issue with a 3 PH 10HP 2 pole electric motor. With no load on this motor it is drawing close to maximum amps (13 to 15 amps). The application is a multiple stage water pump. I completely moved the motor from the pump and still drawing close to maximum current rating. The motor gets very hot to where you cannot touch the frame.

I always thought motor with no load draw about 35% of motor name plate rating…

Thank in advance for you input…

rmonroe

It does if the motor itself is not the problem which it is in yuor case
yuo've got a bad bearing or something else mechanically wrong with your motor. The stator itself is probably fine but its definetely fighting excessive friction

Disconnect the power and try spinning the shaft by hand, if it does not spin freely the bearings are suspect. Measure the resistance of the windings, if they are not balanced phase to phase, the windings are suspect.

randy said:

I realize I'm off the path of PLC's, but I need the help.

I have an issue with a 3 PH 10HP 2 pole electric motor. With no load on this motor it is drawing close to maximum amps (13 to 15 amps). The application is a multiple stage water pump. I completely moved the motor from the pump and still drawing close to maximum current rating. The motor gets very hot to where you cannot touch the frame.

I always thought motor with no load draw about 35% of motor name plate rating… Thank in advance for you input… rmonroe

Click to expand...

Regarding bench test of motor and still running hot
1. Make double sure you have correct phase to phase voltage all three phases
2. Make sure all 3 phase currents are within 3 to 5% of their average. If they are your motor is sound winding wise at least for now.
3. Megger motor to ground - less than 1 meg consider rewind or replacement.
I would guess also that it may be bad bearings. Is this motor mounted vertical or horizontal? If vertical ensure your bottom bearing is able to take thrust of motor and (maybe) pump impeller or make sure pump impeller thrust bearing is OK.
Check for shaft endplay on pump regardless of vertical or horizontal.
You may get lucky and find fan is loose on shaft and not cooling motor. While fixing this go ahead and replace bearings.

Depending on budget and how many identical setups I would consider buying a spare motor. If it was severely overheated for a long time period (one or two hours or more) the insulation may be damaged and that will not cure itself only get worse over time.

Dan Bentler

motor

Want you need to do is a DLR test on all 3 phases ab,ac,bc
the wrl needs to be within 5% of each other
exp.
ac=.69
ab=.69
bc=.30
bad motor .
These will cause the motor to pull high amps.
you can meg the motor and brige the motor and it can show good but if it is not within 5% on a DLR test then the motor will be bad.

What is a DLR test?

If its the same alltest tester that we use (motor winding tester) then just use this to check for shorted turns and shorted bars in the rotor. Much better than a resistance test.

yes it is the same , but we all carry BMM2500 that will meg and do DLR , If the motor is less then 200 hp we do not get the Allltest out because down time will cost more then a 200hp motor ,Because lets look at this .If we are call on a motor that is tripping overloads then the first thing is to do a meg and a dlr if nothing is found then we couple and run motor if there is not a bearing issue and the motor is pulling less then 1/3 of FLA then we look at mech. issue(gearbox ,production so on)But if the motor is pulling more and down time is a issue we just change the motor ,but if the motor cost more then down and we have the or we have the time we will do all the ALLTEST.

Hi Randy, other than bearing failure. Check connections at the upstream devices..disconect, motor starter or any terminals. Also check those devices for good continuity.

Just a thought.Is this a new installation or was this operational before? If its a new installation, I suggest that you should also check your connection(just to be sure that all the leads in the terminal box are connected correctly as indicated on the motor nameplate) and the rated voltage on the motor nameplate.

I may be way OT with this, but why is it a guy states early in the day ' I have a problem..' and all you enlightened gents contribute years of knowledge to help solve a problem and over 12 hours later the OP is nowhere to be found.

I can only assume:

-Problem not all that serious
-I'm at home sleeping and will respond during night shift after 12am

Must be getting old - we used to used a growler and feeler guage to test for shorts - even made our own growlers!

Is the voltage and connections correct.
if i put a 230 volt motor on 400 volt it will run, however it will take much amps.
are there three fases and not only two, are the six currents the same?