CT's relocated line side to load side of soft start- any issues?

[housemoney]

The details I received were "CT is used to control the equipment so we originally put it on the line side of soft start in order to not throw any erroneous readings. The capacitor bank contractor asked if they could move those to the load side of soft start in order to tie in the capacitor bank. Will we end up having any issues if we move that CT on the back side of that soft start?"

I believe their control system is just watching current draw for verifying run status, so I'm pretty certain line or load side would not make a difference?
Not sure what specific "erroneous issues" they're referring to, anything I'm not seeing here?

 

[mayanees]

I don't see a difference either, whether they're mounted line or load. Particularly since the soft-start switches over to the bypass contactor after the motor has started.

 

[zbang]

Are they asking because it'll make things easier for them or because of a real technical reason? Sounds like the first. Also, if the CTs are before to "avoid erroneous readings" will that still hold after moving? Yes when the bypass closed, but how about before? (Not knowing the control system, that's impossible to say.)

 

[Jraef]

Doesn't matter where the CTs are.

If this has to do with PFC capacitors, make sure they are using an PFC isolation contactor and only connecting the caps AFTER the soft starter is in Bypass. If you have them on-line at the same time, it's a race to see whether the SCRs or the Caps fail first.