VFD rating

[unnikri57]

I have a situvation where my load is 17.5 kw and is fixed to a motor 22 kw ( since 18.5 kw not readily available) can i run the system with existing 18.5kw VFD.

 

[che12345]

" #1. I have a situvation where my load is 17.5 kw and is fixed to a motor 22 kw ...#2. ( since 18.5 kw not readily available) ...#3.can i run the system with existing 18.5kw VFD".
1. The load is 17.5kW, but the motor is 22kW. Fine, no problem.
2. since 18.5 kw not readily available ... do you mean 22kW is not readily available? You may use any that is >22kW that is available.
3. Yes, you can. The VFD can be loaded up to 18.5kW. The 22kW motor is slightly over-sized, but no problem.
4. Attention: Set the VFD current limit based on calculated value of 17.5kW. Do not based on the motor current rating.
Good luck and go ahead.
Che Kuan Yau (Singapore)

 

[LionelHutz]

It depends on the load. For something like a pump or fan it'd probably work. For a load that is hard to start like a loaded conveyer, it might not start.

 

[FacEngrPE]

It is likely that autotune will fail when an 18.5kW drive is applied to a 22kW motor as impedance will be out of bounds. Manual tuning might succeed. Might also result in an abnormally short service life.

 

[jraef]

I have run a 100HP motor from a 75HP drive for over 3 years on a conveyor. I didn’t have any trouble with autotune, but I’m not willing to declare that any drive will not. Everybody uses their own secret sauce algorithm. We set up the current limit at the drive’s capacity.


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