Polarization Transformer Basics and Inverter

[Jonaron]

Hi All-
I have a 1987 40DC with a 50 amp shore plug and a 30 amp shore plug. 240 volt generator.
I have what I believe are Jefferson Polarization transformers that feed two separate hot legs of the Breaker panel and a white neutral buss. The 240v breakers are split pretty evenly on the 2 legs of the ac panel, as are the 120v breakers.

As far as I understand, if I have 50 amp 240v service coming in from the shore, or the generator running, the transformer will send 2 x 120v out of phase signals to the legs of the panel, while also eliminating the risk of reverse polarity.
Is that correct?

When I am plugged in to the 30 amp shore panel, are the leads from the transformer to the two ac panel legs also 2 separate 120v leads but 1/2 the amperage?? Are they also out of phase?

Thanks!

[chuckbullett@gmail.com]

Hi All-
I have a 1987 40DC with a 50 amp shore plug and a 30 amp shore plug. 240 volt generator.
I have what I believe are Jefferson Polarization transformers that feed two separate hot legs of the Breaker panel and a white neutral buss. The 240v breakers are split pretty evenly on the 2 legs of the ac panel, as are the 120v breakers.

As far as I understand, if I have 50 amp 240v service coming in from the shore, or the generator running, the transformer will send 2 x 120v out of phase signals to the legs of the panel, while also eliminating the risk of reverse polarity.
Is that correct?

When I am plugged in to the 30 amp shore panel, are the leads from the transformer to the two ac panel legs also 2 separate 120v leads but 1/2 the amperage?? Are they also out of phase?

Thanks!

Hi- Can you provide a photo of the transformer name and specification plate? I believe they are isolation transformers. And no, they’re not out of phase. They eliminate the risk of stray ground currents between the ship service and shore pedestal.

There should be be a full set of electrical schematics for the boat available, or even aboard.

best of luck

[madhatter1]

The isolation transformer is fed power from the "street" wires. Through the transformer windings what comes out is either exact voltage of the 240 or stepped up voltage of the 120 (which hits 2 windings so that's how you get 240 from 120). The advantage of an isolation transformer is that your boats power wires onboard do not "touch" the street wires. Really big thing today on docks with new GFI breakers that many times trip from older boats. I have an isolation transformer and can plug in anywhere with no issue.

As for inverter wiring questions I couldn't help other than make sure your neutral and ground are connected and bonded in the correct locations. Be aware that the instructions that come with the inverter may not be correct on this.

[SKYCHENEY]

I think isolation transformers were on the 53 and up. The smaller boats had only polarization transformers. Your wiring schematics will tell you what you have and how its wired.

[Jonaron]

Skycheney I believe you are correct. I am pretty sure these are polarization transformers and not isolation transformers. And yes they probably are out of phase, because that is how 240 generally works in the US is that the two hots are out of phase with each other and share a neutral. I'm just curious what's happening when it's taking 30 amps in, I guess I could read this with meters at some point.I guess I was hoping someone would have a general knowledge of these and how Hatteras used them, even though I know that every system's a bit different.I do not have the schematic or else I wouldn't be asking the question!My manual has a pretty basic drawing of all of this, definitely not a schematic. I haven't had any luck reaching Hatteras lately, do any of you have any leads on that? Seems like they were bought by a larger company and all I've been able to get is a machine and no call backs.Thanks

[Pascal]

. And yes they probably are out of phase, because that is how 240 generally works in the US is that the two hots are out of phase with each other and share a neutral.

Just to be clear, US 240v doesn’t use or share neutral only the two hots on opposing phases and of course the ground. The only time you use N on a 240V appliance is if it needs 120v for control or electronics