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Anonymous Poster

controling kva of maximum demand.

11/06/2008 7:43 AM

how does one control maximum kva using logic relay for 3 phase induction motors?
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Anonymous Poster
#1

Re: controling kva of maximum demand.

11/07/2008 3:48 AM

Hi Guest

Its simple, you have to increase your copper and core pack.
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Anonymous Poster
#2

Re: controling kva of maximum demand.

11/08/2008 6:12 AM
Hi Guest,

It is Simple ...

1. Use Capacitors of Appropriate size in Out going Terminals of Starter.

2. Use VFD - Variable frequency Drive Controllers that provides acceleration control as per torque requirements & maintains near unity pf ( 0.93)

3. Use Soft Starters.

4. Logic relay demand controller shall provide you protection against Excess demand on the supply system. But in herently shall not reduce the motor kva demand. For reducing motor kva demand, you may have to chose any of the above 3 methods.

regards

guest.
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Anonymous Poster
#3

Re: controling kva of maximum demand.

11/09/2008 8:59 AM

Allen-Bradley, GE, Siemans and others all provide "softstarts" and Variable Frequency Drives (VFD). The VFD being the costliest.

Or, you can shed other loads within the system when starting the larger motor. Then bring them back in a sequeced way.
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