Bearing Fluting Specialists Stop the Attack at the source
High Percentage of small motors have huge Reliability and Energy Efficiency Gains.

High Percentage of small motors have huge Reliability and Energy Efficiency Gains.

Wednesday, August 2, 2023

Upwards of 20% of small Motor have Termination Defects.

A very common defect found with small crimp lugs is a high resistance termination.

A crimp lug often used for small electric motors with cable size 6mm^2 or below are color coded with a preformed insulation barrel.

The Insulation barrel extends beyond the underlying internal metal barrel which makes the termination.

When making the compression with a crimp tool a common mistake is the alignment of the anvil in the crimp tool to the metal barrel. The result is a partial or full miss of the compression zone which creates a high resistance termination.

Compression Zone just touched the Metal Barrel

As the insulating material is compressed along with the Metal barrel it is difficult to see if the termination has been made correctly. If not aligned correctly or not checked once compressed the high resistance termination heats up under start conditions.

Compression Zone alignment caused High Resistance Termination

This heat (Losses I^2R) oxidizes the copper surface and loss of copper annealing and the copper strands. Become brittle. The oxidation further causes resistance increase and problem escalates to a failure.

High Resistance Crimp results in Voltage drop to Motor

Embrittlement of the copper due to the heat also risks a strand break adding to the resistance defect.

Motor Testing experience shows this type of defect occurs in approximately 20% of small motors. What often saves the situation is they are lightly loaded, and can last quite some time before failure.

Voltage drop to Motor stresses the Winding

As a result crimp terminations in industry are quite poor, often wrong sized lugs are used as in the case resulting in not enough surface area (Current carrying Area).

A number of possible causes are at hand being, awareness, skills, tools, or pressure to get job done quickly. Rushing the job is false economy as the this will end in repeat failures.  Skills, awareness and tools are easy fixes a simple skill sheet and a toolbox meeting often get results.

The Awareness comes from finding these defects and sharing the results. Motor Circuit Analysis is a very easy method of finding high resistance terminations and should form part of every Electrical Preventative maintenance program.

The other types of common defects are Loose nut between Motor Lead and the Link, incorrectly torque settings, arrangement so Motor Lead, Link and Supply lead have washers or nuts in the current path, debris between termination faces.

When you add up all these commons defects they account for 94% of Motors in industry.

That means the vast majority of Motors can see improvements in Reliability and Energy savings. coach your technical personnel in Gaining Motor Reliability and Returning Energy Savings

Best Practice Motor Management

Gaining Motor Reliability and Returning Energy Savings

No comments yet

Blog  Free Advice on Electric Motor Reliability and Energy Savings

Feel free to Copy Link and use on your Website  (Blue Chain Button)- MENU ABOVE
3Phi Reliability strive to provide interesting and informative topics to clients to Gain Electric Motor Reliability and Return Energy Savings

Gain Electric Motor Reliability & Return Energy Savings

Most of clients make gains on the every first day of implementation. Best Practice Motor Management has a short Return on Investment, improving Electric Motor Reliability and Energy Savings are immediate.