VFD test motor

[chaterpilar]

I have a 75 kw rated 380 volts VSd wich i want test using a small motor 7.5 hp in the workshop before sending it to site.

Now, is there any limit to the minimum size of the motor that can be used on test ( apart from the minimum current setting of the VFD)?

Cheers.

 

[Besoeker]

I have a 75 kw rated 380 volts VSd wich i want test using a small motor 7.5 hp in the workshop before sending it to site.

Now, is there any limit to the minimum size of the motor that can be used on test ( apart from the minimum current setting of the VFD)?

Cheers.

There may be but we routinely test drives up to several hundred kW using a 4kW motor. On one recently, we did use a 30kW motor but that was only because we could reconnect the windings to get the voltage we wanted - 690V in that particular case.

Some drives has an underload feature to detect loss of load. The default parameter set is usually, if not always, to have that function disabled.

 

[StephenSDH]

If it is V/Hz I doubt you will have any issues. If it is sensor-less vector then they recommend not going below 1/3 of the drives hp rating. The drive has a hard time determining motor positioning when it is too same.

 

[Besoeker]

If it is V/Hz I doubt you will have any issues. If it is sensor-less vector then they recommend not going below 1/3 of the drives hp rating. The drive has a hard time determining motor positioning when it is too same.

For a test to ensure basic operation of controls, you can usually select a scalar operation. I think that's what chaterpilar was seeking to do.
But I agree that it's a different matter if you want performance testing.