wiring questions: 40's fridge ( Did I mess things up?)

[bobwilson1977]

I might have ruined my old fridge. Anyway, here's the deal. I bought a 1940 GE fridge last week. The wires had been yanked out of some sort of junction box. The box was gone. Now- this is where I might have totally messed up. I tested the compressor by directly wiring it to a plug. It worked great. So I then replaced the rest of the wiring.

The compressor has 3 wires: one green, one black, one white. The green one goes to the thermostat. I re-wired this and it worked great. I decided to let it run for awhile to make sure things were alright. It ran for 5-6 hours before I turned it off for the night as I have more work to do on it.

This morning I turn it on and all is well. Still works like a champ. I come back from breakfast and it is off. As in no adjustments to the thermostat did anything. Figuring the thermostat had died I again directly connected the black and white leads to the leads of the plug. Nothing.

That said- after looking around, I am fairly sure that this had a starter relay at some point. That is now gone. So first thing- did I just ruin the compressor not running a relay? It seems weird that it ran fine before and now doesn't. Or does it need a relay to start again?

Any advice or thoughts would be appreciated,

[glennac]

Well since your such a handyman there you shouldn't have any problem checking out your compressor to see if it is shorted to ground (no resistance) or open. Why would you want to mess with a antique frig anyhow. Thank you very much

[Phase Loss]

Here's what you're going to want to do, step by step.

Take that 1940's fridge and throw it away.

Go to your local appliance store.

Buy a 2013 fridge

Take it home and plug it in

Never touch the wiring on it.

enjoy years of refrigerated goods.

[bobwilson1977]

Here's what you're going to want to do, step by step.

Take that 1940's fridge and throw it away.

Go to your local appliance store.

Buy a 2013 fridge

Take it home and plug it in

Never touch the wiring on it.

enjoy years of refrigerated goods.

Uh... that's sort of not what I was asking about. These old fridges actually work quite well when they're repaired and I have a few that are actually more efficient than the newer one it replaced. But moving on, I went out and tested the resistance of the leads. One of the combinations with the green and one of the other leads showed resistance. The other combination had none. So I get a bad feeling that the windings on the motor are indeed open. That sort of sucks.

[icemeister]

Units from that era typically used a "hot wire relay" as the primary starting component for the compressor. It's purpose was twofold. One to de-energize the start winding when the compressor comes up to speed and also to protect it from an overload condition.

I suspect that's what once was in that junction box.

[Snapperhead]

was the compressor still hot when you checked it ?

It might have tripped a overload switch inside

If you get resistance back on the terminals after its cool , you just got lucky , if not , your luck just ran out

[bobwilson1977]

I believe the compressor is hosed. I tested the resistance and there's basically none on the starter coil. Crap-ola. So basically I made a pretty dumb mistake.

That said- I'm wondering what options I have here. There's a few places that rebuild vintage compressors but the cost of shipping and the work involved would be pretty expensive. Other options I'm thinking of would be to get the capacity numbers off the old one and size a modern replacement for it. I would need to fabricate a chassis for it if I did that. I've seen a few places that carry rebuilt compressors.

[Freightshaker]

If it was mine, I would try to cross it over to a new compressor. It might be a tough road but I understand wanting to keep it. If we have one pass through the shop guys just about fight over it. When they are cleaned up they are pretty sweet.

[bobwilson1977]

Yeah, that's what I'm looking into doing. This is totally alien territory to me. It has a 1/8 hp compressor in it now so I'm not sure what to look for as a replacement. I'll need to fab up a frame for it which isn't a problem since I can weld stuff. I like the fridge a lot. I have a 50's fridge in the kitchen and a 50's stand up freezer. Both work like new and believe it or not, use a LOT less electricity.

[coolperfect]

One of the guy's at the supply house around here,has a monitor top.The thing is freakin nice! https://www.google.com/search?q=moni...pCG6ZuQPGf-jM:

[bobwilson1977]

The monitor top was the first fridge to use a totally sealed compressor unit. Some say its the best compressor ever made, which might have some truth in it seeing as how a lot of these still work, almost 90 years on.

[Phase Loss]

Gee whizz!

it was the best compressor ever made and ran for 90 years...until you laid hands on it!

better call someone who works on refrigerators.

[bobwilson1977]

Gee whizz!

it was the best compressor ever made and ran for 90 years...until you laid hands on it!

better call someone who works on refrigerators.

Yeah I know. Don't rub it in too much as I feel pretty rotten about it. Anyway, as this fridge used Sulfur dioxide, I can't simply replace the compressor and call it a day. Looks like the "fix" is going to be finding a donor fridge and using its evaporator coil, compressor and whatnot and install this instead. Its going to be a major project assuming I do it.

[coolperfect]

Hold off on it, we are going back to Sulfur dioxide,may find a compressor for it.

[bobwilson1977]

Hold off on it, we are going back to Sulfur dioxide,may find a compressor for it.

I did some more reading and one thing that was on this site was the mention of using MP39 as a replacement refrigerant after the system got a nitrogen purge. Apparently I'm going to need to do a lot of research before coming to a conclusion on this one.

[bobwilson1977]

I did some more research. It would be impossible to re-use any of the old system in this as it works totally differently from a modern system. The innards are also permanently contaminated with oil and that will ruin any new compressor.

So I have one option it seems. It will be a lot of work but not impossible. It would consist of removing the old condenser and disconnecting the original evaporator. I would then need to either find a donor fridge or find either used or NOS parts online, install the replacement modern condenser on the back, install a new evaporator up top and install a new condenser in place of the old. The fridge totally comes apart and the top comes off allowing you to get at all of the components. Seems like people give away 80's and 90's fridges around here all the time, so the costs to do this might be inexpensive but again- time consuming.

[VTP99]

Units from that era typically used a "hot wire relay" as the primary starting component for the compressor. It's purpose was twofold. One to de-energize the start winding when the compressor comes up to speed and also to protect it from an overload condition.

I suspect that's what once was in that junction box.

Hi icemeister !
Do you have any more info on that electric setup ?
TIA,
VTP

[VTP99]

[QUOTE=bobwilson1977;15246231] I tested the resistance and there's basically none on the starter coil.

What is "basically none" and how did you test it ?

[bobwilson1977]

[QUOTE=VTP99;15261641]

I tested the resistance and there's basically none on the starter coil.

What is "basically none" and how did you test it ?

There are 3 wires that lead to the compressor: 1 black, 1 white, 1 green. I tested combinations of the three and only get resistance between green and white but nothing else. There should be two leads that have a smaller amount of resistance with the primary coil showing the most. As a last resort I also connected the black and white, then combinations of black white and green to 110 volts. Nothing. The unit had been working before. Then it stopped. So I assume the starter coil fried. Again- my bad as I didn't realize the starter relay was missing.

[icemeister]

I did some more research. It would be impossible to re-use any of the old system in this as it works totally differently from a modern system. The innards are also permanently contaminated with oil and that will ruin any new compressor.

So I have one option it seems. It will be a lot of work but not impossible. It would consist of removing the old condenser and disconnecting the original evaporator. I would then need to either find a donor fridge or find either used or NOS parts online, install the replacement modern condenser on the back, install a new evaporator up top and install a new condenser in place of the old. The fridge totally comes apart and the top comes off allowing you to get at all of the components. Seems like people give away 80's and 90's fridges around here all the time, so the costs to do this might be inexpensive but again- time consuming.

I don't know what you may have read, but I know that back in the 1940's and 1950's my father did a boatload of SO2 (and Methyl Formate) conversions to R12 with no problems, mainly because the compressors all used the same mineral oil.

I see no reason to abandon entire system as the evaporator, condenser and related tubing should work well with any new refrigerant and properly sized compressor.

BTW...out of curiosity...does this unit have a high side float?