Motor Starting Current and Transformer Voltage Drop

[IndianTechEngg1001]

When we start a large motor it is having a large starting current which loads the transformer causing the voltage drop.

If I keep this starting Motor MVA lower than the Transformer Short Circuit MVA. Can it be of any help in controlling the Voltage drops?

Thanks
ITE

 

[rbulsara]

Yes.

Rafiq Bulsara

http://www.srengineersct.com

 

[IndianTechEngg1001]

Thanks rbulsara

 

[rbulsara]

You still need to do the calcs. Lowering of starting kVA will help but how much? That depends on the details.

Rafiq Bulsara

http://www.srengineersct.com

 

[cosfi]

I have to start motors Direct on line.How can i keep the starting motor MVA lower than the Transformer s.c MVA.
Because of DOL i think, i must change transformer ratings.

 

[rbulsara]

or explore reduced voltage starters.

Rafiq Bulsara

http://www.srengineersct.com

 

[rbulsara]

Keeping motor starting MVA below transformer SC MVA is no guarantee of acceptable voltage dip. As indicated before do some calculations or have someone do it for you.

Rafiq Bulsara

http://www.srengineersct.com