PM on motors

[Jen0912]

I've been tasked with creating a preventative maintenance checklist for motors. I was wondering what types of tests should be run that won't damage the motor and how often the tests should be run.

Currently I have: check voltage, and amps of all the phases and phases to ground, megger tests, and PI tests if the megger test results in something lower than 5,000 MegOhms. Plus I have the inspections and checking connections, lubricating, and cleaning.

 

[jcarrr]

Listen to the the bearings with and without a stethoscope and learn to tell the difference between happy bearing and unhappy bearings.

John C

 

[Skogsgurra]

A stetoscope (or a piece of wood) is great. But a very subjective method. It takes a good ear and good judgement.

Better use a vibration analyser. There are portable ones and there are fixed installations. Measure with regular intervals and plot vibration levels over time. That will give you an early warning so you can change bearings (or re-align) before you get a costly breakdown.

Google "vibration analysis" for more facts.

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[sands]

A stetoscope (or a piece of wood) is great. But a very subjective method. It takes a good ear and good judgement.

Better use a vibration analyser. There are portable ones and there are fixed installations. Measure with regular intervals and plot vibration levels over time. That will give you an early warning so you can change bearings (or re-align) before you get a costly breakdown.

To add to Skogs reply. Trending is the best Proactive Maintenance approach to many applications. Vib analyzers can also be used in the greasing process by listening to the bearing while greasing. Regreasing a motor has always been problematic until vib analysers came along. Listening with the analyzer, initially the bearing will quiet from the application of grease. Stopping at the low noise point may not provide enough reserve grease. With each shot of grease accoustic emissions will rise somewhat, then fall again when excess grease is able to purge away from the moving elements. If the accoustic signal increases but does not come down, discontinue greasing....or discontinue greasing when you have reached the calculated maximum volume.
Spock

 

[Zogzog]

While you are at it google EMAX testing. I think if you add the suggestions above to what you have already you are good, but EMAX testing is gaining popularity.

 

[aolalde]

To have a controlled predictive life expectancy of motors, the trend performance of motor parameters is the best tool. See

http://www.pdma.com/PSHOME.html

for an example of modern predictive tools that include parameters collection, data base file and analysis software.