Batfastard
Electrical
- Jul 9, 2006
- 4
I recently installed four VFD's for four air handlers. These are 208v 3 ph motors from 10-20 hp. Three of four drives are running well. Motor currents and temperatures are good at 60 hz.
A 15 hp drive has a line reactor which is excessively hot at 60 hz. It does vibrate quite a bit as well.
I have tried two different reactors with the same result.
Motor currents are normal and the electronic drive does not appear to be having any problems. The system is working normally except for the hot reactor. Reactor current is about 75% of full load.
The supply conductors are about 125 feet long and oversized at #2 rw90.
The motor is original and not designed for invertor duty.
I performed a harmonic study on these systems as well as the building service. Although intrepreting the results are a little bit over my head, I am on the understanding there are no immediate problems with the results. THVD on this drive is about 1.6% and THID 55%.
I ran a separate ground wire #6 back to the station bus.
Any ideas?
Batfastard
A 15 hp drive has a line reactor which is excessively hot at 60 hz. It does vibrate quite a bit as well.
I have tried two different reactors with the same result.
Motor currents are normal and the electronic drive does not appear to be having any problems. The system is working normally except for the hot reactor. Reactor current is about 75% of full load.
The supply conductors are about 125 feet long and oversized at #2 rw90.
The motor is original and not designed for invertor duty.
I performed a harmonic study on these systems as well as the building service. Although intrepreting the results are a little bit over my head, I am on the understanding there are no immediate problems with the results. THVD on this drive is about 1.6% and THID 55%.
I ran a separate ground wire #6 back to the station bus.
Any ideas?
Batfastard