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Home » Public Forums » GMCnet » How to disconnect my Norcold refrigerator from A/C 120v (I'd like to run my refrigerator only on 12V D/C and there's no A/C plug to disconnect)
Re: How to disconnect my Norcold refrigerator from A/C 120v [message #317396 is a reply to message #317391] Thu, 11 May 2017 18:09 Go to previous messageGo to previous message
Matt Colie is currently offline  Matt Colie   United States
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
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Senior Member
A Hamilto wrote on Thu, 11 May 2017 15:41
Ken Burton wrote on Thu, 11 May 2017 14:07
That is interesting. On my coach the outlets are on a GFI breaker while the refrigerator is on a breaker by itself.
Well, so much for that idea.

As near as I can tell from the manuals, GM never hooked up the 120VAC fridge power on the early models. When I took the OEM fridge out of the Sequoia "donor" to put in mine, I never found a cord. There was a two-spade connector on the "chattering protector" for AC connector, but no cable/connector from there.

I have a bigger Norcold that came out of a Palm Beach that had a regular power cord from the connector on the "chattering protector". So I bought/assembeld the stuff to make a cord/connector and made one identical to the Palm Beach fridge for the Sequoia. I used 120VAC to test it for functionality. I have never tried it on 12VDC.

And if your eyes haven't glazed over yet, I think I know the reason that GM never hooked up the 120VAC to the fridge.
A. The Onan can run slow or fast and the frequency will be outside what the swing-motor compressor will tolerate, and it won't last.
B. There is no reason to use the 120VAC input. Underway, its power originates from the engine alternator, through the isolator, the converter, to the fridge. "Dry" camping, it gets its power from the battery like it has to. On shore power or Onan, it gets power from the converter.

To summarize: There is never any need for it to run on anything but 12VDC, and the generator can kill it graveyard dead on its 120VAC if it runs too fast or too slow.

If I was going to keep it and use it, I would gut the electronics to eliminate the OEM "chopper" (square wave) inverter and install a 12VDC-to-120VAC 60Hz pure sine wave inverter connected to a 5:1 transformer to get the 24vac that the compressor wants.

Well, Here is another set data points....

My 73 23 (S/N 1650) did have a line cord and a plug.
The reefer was not on its own circuit, but that is not what killed it.
The only GFI are those I added.

There is a reason to keep the 120V power available. It just may not be worth the risk. If you have a coach that has the house bank in the front and you are trying to recover it with the buzz box powered from the APU, the line loss though the 25' of #10SAE wire (note - NOT AWG) is enough to make this operation problematic - As in the best charge rate you can get is about 25Amp.

That is my final answer and I don't need to call a friend.

Matt - Just greased his Lenzi hubs for the first time


Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
 
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