3-phase motors: unbalanced current system
3-phase motors: unbalanced current system
(OP)
Hi, I´m working with motor commissioning, my doubt is: when I measure the phase-current of a 3 phase assincronous motor, I got differences in order of 2% between the value of current of one phase and other, when can I say that the system is unbalanced, and which are the risks that I have working on a unbalanced system
Thanks
Thanks





RE: 3-phase motors: unbalanced current system
2% unbalance current is probably OK, and may be caused by voltage unbalance or something like stator-winding dissymmetry.
Search this site for a fair amount of discussion on the matter, using keywords “ unbalance “ and “ imbalance “.
RE: 3-phase motors: unbalanced current system
http://www.joliet-equipment.com/operation.htm
for:
If the variation in voltage does not exceed 10% above or below normal, with all phases balanced. Voltage unbalance should not exceed 1%.
However, the 1% voltage unbalance corresponds to the larger current unbalance.
And,
http://www.elongo.com/pdfs/voltages.PDF
http://www.siemp.co.zw/Acrobat%20Files/module06.PDF
etc. for more info
RE: 3-phase motors: unbalanced current system
See also Thread237-70765 "how to calculate kW losses in an unbalance motor". This may provide you with additional useful information.
Regards,
GGOSS