Connecting equipment requiring a neutral onboard a vessel.

[morty67]

Hi guys.

Pretty much every piece of equipment that arrives on my vessel is wired just to require 3 phases and earth. But someone has decided to be awkward and bring on a HPU that requires 3 phases, neutral and earth (the neutral is required as part of the control system)

Part of me is thinking about connecting the neutral to earth, but theres an alarm bell in my head ringing.

Any ideas?

 

[davidbeach]

Listen to that alarm bell. Provide an isolation transformer if necessary to provide the correct circuit configuration but don't use ground as a current carrying conductor.

 

[zeusfaber]

vessel = ship? If so, significant effort has gone into isolating your three phase supplies from earth, and those alarm bells are doing a good job.

Have you found out what the control system does with the neutral (and how much current it would need to sink)? It might well just be supplying a transformer to provide low voltage power to the controls - in which case changing the transformer to one you can simply connect between two phases may be the tidiest solution.

A.

 

[morty67]

Cheers guys, yeah pretty much backs up what I was thinking anyway. We have another subcontractor onboard that has a HPU that can be used, the onus was on them to ensure the equipment they brought on was fit for purpose. Luckily not a show stopper, but was just curious if there was an easy solution!

 

[davidbeach]

Supplying the right equipment the first time is always the easiest solution. ;-)

 

[waross]

The simple solution for control power is a control power transformer connected line to line.
If for some reason a true neutral is needed, you can use three small transformers connected wye delta. The delta voltage is unimportant. The primary wye point will provide a true electrical neutral.
Don't ground the wye point neutral.


Bill
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"Why not the best?"
Jimmy Carter