Yaskawa A1000

rpoet said:

So.... where does that leave me? Can I safely connect the A1000 drive to corner-grounded 240V power without letting the smoke out or not? Do I have to remove the MOV filter network in the front end / is that possible?
-rpoet

Click to expand...

It's your call, but the only SAFE option in my mind is to install a "drive isolation transformer" ahead of the drive. It would be 230 Delta primary, 230/133V Wye secondary. You don't USE the 133V L-N voltage of course, but it creates what the VFD components are looking for, a solid reference to ground on the input line voltages.

Example only, not an endorsement:

If you were (hopefully) going to use a Line Reactor, you can eliminate that as this transformer will provide the same level of drive protection as the reactor would have.

jraef said:

It's your call, but the only SAFE option in my mind is to install a "drive isolation transformer" ahead of the drive. It would be 230 Delta primary, 230/133V Wye secondary. You don't USE the 133V L-N voltage of course, but it creates what the VFD components are looking for, a solid reference to ground on the input line voltages.

Example only, not an endorsement:

If you were (hopefully) going to use a Line Reactor, you can eliminate that as this transformer will provide the same level of drive protection as the reactor would have.

Click to expand...

The compressor is a pre-packaged unit, and comes with a line reactor installed.

I got written confirmation from Yaskawa that the drive would be OK on corner-grounded delta power, for whatever that's worth. They also said I should install "ground fault protection" on the circuit supplying the drive, and when I pressed the tech he couldn't really explain why or how that would help; it seemed like a CYA to me, and goes to your point regarding Yaskawa not really understanding delta power.

Anyway, the drive powered up without any issues, and is running without a transformer. Time will tell if issues crop up.

Ugh. I hate corner-grounded delta power.



-rpoet