VFD Power Feed

[safspir]

Hi Folks,
I was called in to assist with the cable pull for power feed to a couple of ABB VFDs. They will be controlling two 75 hp 3 phase 480 motors, non-simultaneous use.
The cable provided is DLO 3/0 to be run parallel, 2 runs of 4 cables each, 60 and 120 feet respectively.
They have specified that the fourth conductor is to be a ground, attached at a point near to the breaker being fed from the main buss.
Steel hull vessel. Does anyone care to comment on the need for this grounding conductor or the advisability of making parallel runs for this application?

 

[itsmoked]

This would've been better in the electric motor and controls forum.

That said, VFDs are fierce noise generators. Some of it is coupled back down the ground. I can easily see them not wanting any ground currents working their way all around the ship to get back to the generator. So it's probably for the noise more than safety - which is probably where you're coming from.

Keith Cress
kcress -

http://www.flaminsystems.com