Motor Voltage Drop at Starting time


We're having a problem with a motor that has a big voltage drop (around 18%) only at the starting time. It's a 800HP motor that works with 99A and 4000V. A mechanical check has already been done on it, and everything looks fine, so the proble is related to power distribution I believe.

Any ideas?

Thank you


asked 7/29/2013
  • It looks like the cables and switchgear are ok because the problem is only at the starting time, or what do you excatly mean by this?

    We are know doing some calculations in order to check if our current transformer is goof enough to supply our motors. Do you know how to do this?

    Tahnk you
    - jcdelao 8/5/2013

1 Answer

This answer has been selected by the question author as the best answer.

Has the voltage drop calculation been validated before ordering of cables and switchgear? Particularly for high inertia motors, you will have to factor in this input. 

Secondly your power source could be weak which is not able to support the high capacity motor starting current.

Please check and revert.

answered 7/31/2013 Pattabhiraman 74

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