chiller motor inrush current issue

Thread Starter

tahir mehmood

Joined Jun 28, 2013
dear professionals;
we have a 2000 ton centrifugal chiller, the supply voltage is 6600 V, three phase star start. the FLA=145 A, the Inrush current is 823 A, LRA=823A. my doubt is how much inrush current it will take when the motor is decoupled, and after the initial inrush duration is passed then how much current the motor will take in decoupled state.

thanks and regards.


Joined Jul 13, 2008
You are specifying a motor disconnected from its normal load - 3 phase ? it will start with a bang, and I don't think there is a meter fast enough to note the pulse. it will pulse far less that its nameplate loaded running amps


Joined Jul 18, 2013
It was very common, and really necessary to start large motors such as those driving compressors etc off line, It should take considerably less than FLA when started off line.
This wouldn't be a induction motor, synchronous when in run by any chance?


Joined Nov 7, 2013
Inrush will be the same. Shorter duration.

No load current depends on the type and rating of the motor.

Load of induction motor will be reactive. Drawing lots of current out of phase with voltage.