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New motor winding design 'eliminates bearing currents'

New motor winding design 'eliminates bearing currents'

RE: New motor winding design 'eliminates bearing currents'


Are properly designed and built motors at risk to develop dangerous bearing currents?

Wolf
www.hydropower-consult.com  

RE: New motor winding design 'eliminates bearing currents'

There are of course already a lot of measures we know about for preventing or minimizing bearing currents. Insulating the bearings comes to mind.   The configuration of the PWM power supply and cable also can play a role as I'm sure Gunnar would chime in.

The role the windings play in the process is related to their  capacitance to ground. Given that the windings need to be in intimate contact to the core for heat transfer reasons, and then insulating materials tend to have high dielectric constant, I have a hard time understanding what would be done to the winding to reduce this capacitance.   

=====================================
(2B)+(2B)'  ?

RE: New motor winding design 'eliminates bearing currents'

I was a bit confused to read about things that have been known for so long and still presented as news items - until I found out that the articles were ten years old. And much of the contents wasn't new even then.

The ABB patent (post by dArsonval (Electrical)) is somewhat newer. But, as far as I know, the patent (first date on the letter is october 2003) has not led to any changes in ABBs motors.

The thinking behind the ABB patent is correct. But the practical implications don't seem to allow standard motors to be made that way. And, still, the winding technique only addresses the problem with inductively coupled voltages and, perhaps, capacitively coupled voltages. It does not help against frame voltage and externally coupled energy.

 

Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

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