vfd trouble

[puckman]

we have a vfd that seems to drop out on low voltage . does anyone know if vfd's have a internal setting or adjustment for the voltage operating range for vfd's? this is for a old mitsubishi z200 that i can't seem to get info on. also i was told that you can install capacitors to keep it from a voltage drop. any help will be appriciated.
thanks

 

[76nemo]

we have a vfd that seems to drop out on low voltage . does anyone know if vfd's have a internal setting or adjustment for the voltage operating range for vfd's? this is for a old mitsubishi z200 that i can't seem to get info on. also i was told that you can install capacitors to keep it from a voltage drop. any help will be appriciated.
thanks

Meaning dropping out from line sag?

 

[puckman]

vfd

vfd

sorry, it drops out from a large motor starting in plant.

 

[Jraef]

Most VFDs have an internal floor of DC bus voltage below which it will trip, and that is rarely adjustable. Additional bus caps will only help with very short duration sags, as in maybe 1 second or less, but a sag from a large motor starting is usually a lot longer. By the way, do NOT put caps on the AC side, you are asking for trouble.

The better way to approach this would be to solve the motor starting sag problem, i.e. put a soft starter on that bad boy.