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Electrical Crimps lead to Motor Failures

Thursday, April 16, 2020

Summary: Electrical crimps in the elctrical circuit of a motor are surprisingly common cause of motor failure.

Poor terminations also area primary ignition cause of electrical fires, they waste energy, and cause an impedance imbalance in the motor circuit.

A motor audit makes an assessment of crimp quality and identifies defects that ultimately decay to a failure.

How to eliminate motor failures from poor termination.

When crimping training, and purchase of the correct tools was implemented at a food manufacturing site it was met with some suspicious looks.  Crimping is a basic skill right!!!!  We don't need that!

Well afterwards I got a number of comments that it was very informative, another words they learnt alot.

The picture above is from that site, a crimp lug overcrimped caused a high resistance termination and the motor lead blew off. It was of no fault of the site trades as it had been overhauled externally.

The motor lead (lefthand phase taped in blue insulation tape) was repaired and put back into service.

It must have been a pretty awkward position as the motor lead was very short, and hence the lug has been bent to get it to fit. This is not recommended and could lead to another high resistant joint failure.

The centre phase have also been overcrimped, and the righthand lead might be ok, but the cable seems very stressed.

Steps to stop motor failures due to poor terminations.

1. Conduct a Motor Health Assessment, whichs tests for imbalances in the circuit. Denergised motor circuit analysis can identify these defects within minutes.

2. The Motor Health Assessment includes a visual inspection of terminations and potential failure modes.

3. Implement a onsite crimp training session, and ensure electrical trades have the correct tools and consumeables.

4. Implement an acceptance testing procedure to stop defects being introduced to your enterprise.

5. Document defect elimination and use the result to lower your insurance risk. Remember these types of failure modes are the leading cause of electrical fires.

3phi-reliability.com can implement this part of best practice motor management, and highly recommend Motor Circuit Analysis with All Test Pro.

3phi-reliability.com

Mark Gurney Gerant 3Phi Reliability Sarl

 

 

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