Prediction of insulation breakdown in a motor

Thread Starter

Vlad Vsky

Joined May 15, 2017
18
In an electric motor, it is important to detect a short circuit fault in one of the windings in its early stage. But, would it be possible to predict the moment in which an insulation failure may happen between adjacent turns in one of the windings ?

In my opinion, if we have a collection of sufficient data, representing the functioning conditions of a motor during a month, it is possible to predict its life time, or in other words, the time interval in which it my undergo an insulation failure.

What are your opinions ?
 

profbuxton

Joined Feb 21, 2014
419
Well, good luck with that!. Maybe taking regular insulation resistance readings may eventually point to a possible failure "at some time" in the future, near or far!. If enough data is collected on similar failures on similar motors under similar conditions you may be able to calculate a Mean Time Between Failure. How accurate it would be in any particular instance, well that is the question.
Remember, not even HAL could correctly predict the antenna unit failure( see 2001, A Space Odyssey).
 

GopherT

Joined Nov 23, 2012
8,012
In an electric motor, it is important to detect a short circuit fault in one of the windings in its early stage. But, would it be possible to predict the moment in which an insulation failure may happen between adjacent turns in one of the windings ?

In my opinion, if we have a collection of sufficient data, representing the functioning conditions of a motor during a month, it is possible to predict its life time, or in other words, the time interval in which it my undergo an insulation failure.

What are your opinions ?

You can't measure exactly when the first on fails but inflation tends to fail as motor temperatures increase with age. At my old company, they kept a logbook of motor temperatures (measured with an IR thermometer and overall motor is inspected with an IRmcamera for hot spots)). The position of the thermometer was the same each measurement, the motor had to be in the same situation (load) at each reading. We Used that mainly for agitator motors and pump motors. Just In the last two minutes of a batch of polymer for the agitator motor and just before the tank is filled or emptied for the pump motors.

You can check the health of bearings in motors and other equipment the same way.

Also, here is a 20-year-old reference. It is only a presentation but I'm sure there is more information out there. It my cost you a few bucks but it answers your question...

http://ieeexplore.ieee.org/document/595213/
 

Papabravo

Joined Feb 24, 2006
17,310
I think your goal will be a heavy lift. Do you know anything about statistics and random variables? Many people try to use these tools to predict the future with varying degrees of success. What it teaches you is how to reframe the question so the answer provides insight without leading you astray.
 

tsan

Joined Sep 6, 2014
116
Partial discharge measurement can be used to estimate condition of insulation. Google search "motor partial discharge monitoring" tells more...

Timo
 

MaxHeadRoom

Joined Jul 18, 2013
23,945
Generally with modern varnish used for wire enamel, plus modern varnish use in the bath dip after the motor is wound, precludes much of the risk of insulation break down, it is generally due to over loading/heating of the windings that are the main cause.
Max.
 
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