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Motor Insualtion level

Motor Insualtion level

Motor Insualtion level

(OP)
I have done a motor insulation calculation below,

L-L voltage:600V
L-N voltage:347V
Motor is fed from VFD
Peak neutral to ground voltage is 200V.

VmotorL-G=200/1.414+347=488V

I am not sure if motor insulation level shall be  calculated this way. Any comments will be appreciated.

PLease note there is neutral shift between VFD neutral and ground.
 

RE: Motor Insualtion level

The VSD harmonics influence on increasing induction motor insulation is still in searching stage. Here attached an extract from the article: New guidelines for variable speed drives + motors by Siemens Automation and Drives and edited by Engineeringtalk
"It is recommended that for supply voltages between 500V and 690V, motors are chosen, from the range offered by REMA [the Rotating Electrical Machines Association] members, with an enhanced insulation system.
These readily available motors may cost between 10 and 20 per cent more than a standard design, but they offer the required assurance against costly failures".
"The BS EN 61800-2 " Adjustable speed electrical power drive systems - Part 2: General requirements" may indicate more".
See: http://www.engineeringtalk.com/news/sie/sie101.html

My opinion is that for 600 V [ L-L ] and Delta connection 1000 V insulation will be fair.
Regards






 

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