Whats wrong in this circuit?

hi expert 

how can get parameter data via drive pad

ebrahimsaadati

hhi all, whats wrong in this circuit? we use field contactor to reverse rotation of dc motor in steel mill factory but the contactor have burned several time. 

Hello,

Welcome to forum. 

Please open new topic instead of posting your query in old topic.

Here I prsume contactor damages power contacts.

How is field contactors control operation? Is field contactor logic is controlled via drive or it is externally interlocked?

Please refer attached sheet which shall help you to wire field reversal contactor control wiring & shall help you to set related parameters.

If it is externally, please check if you have wired aux NC contacts of both the contactors in control logic, which will ensure operation of second contactor only when first one is switched OFF state.

Check an appropriate value of varistor is connected across field winding. You can calaculate the value of varistor refering formula explained in attached sheet.

HTH

THANKS FOR YOUR REPLY.

THIS IS THE CONTROL CIRCUIT OF CONTACTOR: WHAT HAPPEN IF USE AC CONTACTOR?

Hello,

You did not get the point.

Please check & reply below points.

What do you mean by contactor burnt?

1. Is DC coil burnt? If yes, use surge supressor accross DC coil. Please check if contactor control is thru DC drive or external logic? In case of external control logic, use NC contact of contactor as interlock with each other.

2. If contactors power contacts are getting burnt, please check motor field current rating & contactor power contacts rating. Please check the duty cycle of application.

HTH  

What speed is the motor rotating when the contactor toggles forward/reverse?  If the answer is not 0, that's the problem.  When the motor is at 0 rpm for a short period of time, it is electrically safe to toggle the direction contactor.  Are you using the drive to manage the contactor?  If not, consider changing the motor drive configuration so it handles the direction change from an external digital input. 

ebrahimsaadati

hhi all, whats wrong in this circuit? we use field contactor to reverse rotation of dc motor in steel mill factory but the contactor have burned several time. 

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Split from DCM field reversal.