Cleaning 3 phase AC motors while still in service
Cleaning 3 phase AC motors while still in service
(OP)
Am attempting to implement a motor cleaning maintenance program.Most motors are vertical hollow shaft WP1 and open dripproof enclosures.HP ranges from 25 to 300.Voltages are 480 and 2300 VAC 3 phase.I used to work for a refinery and I observed the maintenace techs. cleaning operating motors (running) with some kind of soapy looking substance in a bucket.They would apply it with a brush on the exterior and even splash it on the air intake so it would be forced over the windings while the motor was running.Any suggestions?





RE: Cleaning 3 phase AC motors while still in service
Is there no other way to shutdown the machine to conduct such action? How critical the machine should be in operation?
RE: Cleaning 3 phase AC motors while still in service
For motor in services the following could help:
1.Stop the motor
2.Cut off the power
3.Log Out and Tag out
4.Verify the motor don´t start open the connection box and look for damage on leads and power wires.
5.Take an insulation reading(IR) at 500 V from the CCM and record the reading.
6.Uncouple the motor
7.Made a complete visual motor´s inspection looking for damage in motor parts,couplings or pulley, belts and foundations and for unusual services conditions.
8.Clean all motor´s surface with a dry wype
9.Apply new grease to the bearings.Take out the fan and fan cover.
10.Clean the grease excess
11.wash and clean the fan (If is made with plastic)
12.Clean the cover inside
13 Assembly the fan and cover fan.
14.Couple and align the motor
15.Restore the power conditions and start the motor.
16.Take a voltages, Line Current, frame and bearings temperature readings,and vibration levels.
Remember record all readings.
If you don´t have a good IR readings the motor could be sended to shop or could be dry out on site with a blower, the motor may need dissambled.
Regards
Petronila
RE: Cleaning 3 phase AC motors while still in service
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Cleaning 3 phase AC motors while still in service
RE: Cleaning 3 phase AC motors while still in service
1) Messing with motors that are running or can start at any moment to be flat out hazardous.
2) Generally this would be likely illegal by any local authority like OSHA or against corporate policies.
3) There is not a lot you can do with an active motor. You can do about four things.
A) You can measure the phase currents and compare them to previous readings that are always logged along with comments like the process load.
B) You can measure the vibration and sound at several specific points and log these.
C) You can use a contactless temperature gun on several specific spots and log these, (including the ambient temperature as measured contactlessly on a logical nearby surface).
D) You could measure the RPM with a contactless tachometer and note this in the log.
These various safe, (with the possible exception of the current measurement), aspects should alert you to any critical changes or aging processes going on.
Bearing areas may slowly start rising in temperature, current can increase, vibration increases, and noise increases as a motor ages.
All this falls short in my opinion with regard to "servicing" a motor and are rather "monitoring" the motor in a quantitative useful manner.
Other points anyone?
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Cleaning 3 phase AC motors while still in service
Yes you are right. The above List will be usefull for MOTOR MAINTENACE MATTERS and not for cleaning.My Appologies.
To clean motors in services is very important to be sure about the Technical data sheet of cleaning compounds, solvents or soaps you are using. This products most be dielectric and no corrosive, take account if you clean a motor runing the windings could be exposed to be in contact with the product, if this is not dielectric the winding coul fail. Also the mechanicall parts and grease can be in contact too with this solvent.The connection box,bushings and electrical pipes most be checked looking for wrong juntions.Also You can blow the fan with air.
I am agrree the protection is very important, for it you will need all personal protective elements like glasses and globes (The motor is warm and you will use liquid solvent) the other risk is the motor itself because is running, don´t use innapropiate cloth, the moving parts coul catch the maintenance personal.
Remember perform the job with trained people.
Regards
Petronila
RE: Cleaning 3 phase AC motors while still in service
RE: Cleaning 3 phase AC motors while still in service
I would rather "maintain" myself than the motor.
RE: Cleaning 3 phase AC motors while still in service
That's what a preventive is, but wasn't the case when "cleaning the machine's winding while running" , hence petronila is right. All you suggest will then converge to SAFETY - as i said safety first. The procedure eventually against the corporate agenda on safety likewise to safety agencies enforcing or advocating it at workplace as a set of standard(OSHA, NESC, NEC, IEEE, etc).
Petronila:
"Remember perform the job with trained people." I prefer to say; Perform the job with qualified personnel only. "Qualified personnel" refers to a person who are trained for the specific job and trained with safety issues pertaining the its know trade.
RE: Cleaning 3 phase AC motors while still in service
RE: Cleaning 3 phase AC motors while still in service
I will add one to the list that has happened twice at our plant. If you get a rag anywhere near the inlet of a TEFC fan, it can get sucked right out of your hand and into the fan where it can damage the fan (cheap plastic fans) or just make the vibration go through the roof. I think maybe newer motors have some kind of fine mesh grille to prevent this but ours don't.
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RE: Cleaning 3 phase AC motors while still in service
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RE: Cleaning 3 phase AC motors while still in service
The external parts could be cleanned wiyh out any interruption of service.
Regards
Petronila
RE: Cleaning 3 phase AC motors while still in service
Compressed air was used regularly to clean dry sawdust from open drip proof motors without incident. One motor was inadvertantly missed from the cleaning schedule and eventually caught fire. Compared to that, I can't remember any incidents related to cleaning the other motors when they were running.
Some were not accessible when running for safety concerns and were blown down when they were stationary. Blowing them out when running worked better.
One day someone cleaned a stopped, open drip proof motor with a steam cleaner. It never ran again.
respectfully
RE: Cleaning 3 phase AC motors while still in service
That is something that is out of my experience. We rarely have a need to clean any windings on new VPI windings and when we do, the motor is sent to a repair shop where it can be steam-cleaned afterwards.
For cleaning windings on site while shutdown, the only options I know of are: 1 - vacuum for dust, 2 - spray lightly and wipe with a solvent which will evaporate (choose carefully) and 3 - dry ice which will sublimate.
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RE: Cleaning 3 phase AC motors while still in service
Wow - we're not just talking about cleaning the motors while running but cleaning the windings while running?
That is something that is out of my experience. We rarely have a need to clean any windings on new VPI windings and when we do, the motor is sent to a repair shop where it the stator can be baked afterwards.
For cleaning windings on site while shutdown, the only options I know of are: 1 - vacuum for dust, 2 - spray lightly and wipe with a solvent which will evaporate (choose carefully) and 3 - dry ice which will sublimate.
=====================================
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RE: Cleaning 3 phase AC motors while still in service
old field guy
RE: Cleaning 3 phase AC motors while still in service
Oldfieldguy,..is right. This would require a special attention regarding to unsafe acts. There would be a Hazard/risk analysis, a MSDS of solvents, and other safety provisions.