Modelling a VFD driven motor on ETAP 7.5

[shailesh_excl]

I have a 350 HP VFD driven Motor to be modelled on ETAP for a motor starting study. What value of LRA should i be considering to model it. I am assuming that when the motor is power thru VFD the LRA will come down significantly. But with the bypass switch involved, its adding to my confusion.

How do i model the motor data to accomodate both conditions when it comes to the LRA.

Thanks

 

[weressl]

I have a 350 HP VFD driven Motor to be modelled on ETAP for a motor starting study. What value of LRA should i be considering to model it. I am assuming that when the motor is power thru VFD the LRA will come down significantly. But with the bypass switch involved, its adding to my confusion.

How do i model the motor data to accomodate both conditions when it comes to the LRA.

Thanks

So in the bypass mode it would be the normal LRA and the inertia will give you T/C decay curve.

The ASD has a maximum power rating, ex. 250% of the drive rating for 10 sec. That would be the maximum acceleration curve, the actual curve of course is dependent on the ramp curve and mass to be accelerated.