Isolation transformer location

[intdln]

2004 Mainship 400 Trawler, single engine. Getting only 90 volts in and out on shore power feed switch. Problem may be in the isolation transformer but cannot find it. It's not behind fridge or anywhere else I can find. Anyone know where the isolation transformer is ? Anyone else have this reduced voltage issue? Local dealer no help.

 

[Capt.Bill11]

What's the incoming voltage from the dock?

Does it drop as you put a load on it?

Are you sure you have a transformer?

If you are, is it automatic? Or do you have to tell it whether to buck or boost?

 

[intdln]

Isolation transformer

All voltage into boat is normal and does not drop.. Its one line from main line that feeds outlets that drops. All other lines and switches are where they should be. I have shore power inlets both stern and bow with different cords. Same results. However when gen is running voltage is normal. Mainship specs states that transformer installed but wondering if true. Driving me nuts. Thanks for your response.

 

[Capt.Bill11]

Then it sounds like the problem is just on the one line.

If so, look for bad, corroded or loose connections.

See if it's a bad GFI issue as well. If one GFI protect multible outlets.

 

[intdln]

Isolation transformer

Thank you. All connections secure. Makes no sense.

 

[Capt.Bill11]

You're going to have to trace the drop set by step segment by segment it sounds like.

Bad breaker?

 

[boatpoker]

Isolation transformers are large (think bread box) and if one is fitted (not typical on Mainship) it would be within a foot or so of the shore power inlet.

 

[sunchaser]

Intrinsic

Assuming you have the standard rotating switch between generator, input 1, input 2 and off - that switch may be suspect. With all power unplugged open that switch up and have a look. If not there you then have to go the next breaker and start checking for a bad wire - ground most likely.

Time for a pro in any event, is there a good marine electrician nearby? Many boat fires centered on incoming power connectors so be careful.

 

[intdln]

Thank you

 

[Wxx3]

I had the same problem just a few days ago.

90 volts at the plug, when it should have been 230.

After doing all sorts of things, I finally checked the connection again and discovered the plug was only halfway into the socket. Both UK type plug and socket.

Turned

 

[Bay Pelican]

Size matters. Bay Pelican has an isolation transformer (50 amp). It is very large and it couldn't be overlooked on a 40 ft boat. It is double or more of the size of one of the inverter chargers. It has cables running directly from the shore power inlet, and another set of cables running to the breaker panel.

If you can't find it, it is likely you don't have one.

Given their cost ($3,000 to $7.000 plus), I question why an isolation transformer would be put on a boat without a specific need, certainly not a production run item. Is the literature confusing isolation transformer with galvanic isolator?

 

[intdln]

Thank you.

 

[Capt.Bill11]

"Its one line from main line that feeds outlets that drops. All other lines and switches are where they should be."

If this post is correct and the only line branch that has low voltage is one line that feeds some outlets while every other line has good voltage, it can't be a loose plug, transformer issue or a main switch issue.

Or you would have an overall voltage drop.

 

[mike66]

My next step would be to disconnect the circuit from the breaker and then measure voltage coming out of the breaker. Also measure voltage going into the breaker. Also measure the resistance on the disconnected circuit and make sure it is open between hot, neutral and ground.

 

[intdln]

Isolation transformer found on Mainship 400 Trawler

Located in clothes closet port stateroom behind upper panel. Problem was with it. Fixed.

 

[Capt.Bill11]

Located in clothes closet port stateroom behind upper panel. Problem was with it. Fixed.

OK, great.

So what was the problem?

How was it fixed?

And how was it that the voltage drop was only on one circuit?

 

[intdln]

One of the wires was bad. Hired a pro so did not completely understand. Tks for your responses.