Norge Rollator Repair - 1930's Belt Drive Rotary Compressor

So, I made a little progress on the Norge today. 

First thing was to get the evaporator out and see what sort of condition it is in. To that end, I started by removing the front panel from the controls and evaporator.  Thankfully, with the help of a heat gun, I was able to get it off without tearing up the rubber.

It seems a little forlorn without the cover LOL!

Control just plugs in.

Made in USA by Cutler-Hammer controls.

Got the control bellows, nicely contained in a shroud, so that it wouldn't over-expand if removed. Also got a 5 amp overload heater with melting alloy trip device. All in great shape in spite of the age.

Now for the ugly. The evaporator was full of black crusty stuff and oil.... lots of oil....

The needle valve. It looks awful here, however the needle its self is in perfect condition. I could have sworn I took a picture, but it's not on the card.

This entire bottle of oil came out!  I spilled some as well.

To compensate for the lighter density of R152A, I added a spring to the needle valve pivot area. This takes about half the force from the weight of the float. It is a semi-educated guess. The Frigidaires needed slightly more of the float weight compensated in order to work with R152A. This float is larger, and I expect it to still function. The torsion spring and the silver bushing in the center of the spring are new.

The thimble screen in my hand goes in the liquid inlet port.

I did an internal borescope inspection of the evaporator. Again, the pictures aren't on the SD card. I think the card may need formatting.

As for the compressor, I determined that the shaft will have to be turned down, a sleeve installed, and then the seal can be installed. I didn't have enough sleeve material on hand, and spoiled the one piece I had. So, hopefully tomorrow I can get the eccentric shaft repairs done.

Nov 7, 2018 16:22:15 GMT birkie said:

I'm kind of shocked at the volume of (disgusting looking) oil in the evaporator. Could it have run, poorly, a long time with a low charge (and therefore, float "open")?

Also, it looks like the float itself is trapped in the header, and the valve mechanism simply has an arm with a slot that mates with the float?

Yes I was also really surprised at the amount of oil in there! I believe it did run for a long time wit a very low charge. That is what the Norge manual says causes this to happen, as well.

I took more pictures of the float mechanism and valve etc. but for some reason they weren't on the SD card. The float mechanism has a round cross bar inside the evaporator header, which goes into the slot at the end of the valve arm.

Thankfully the needle and seat were in very good shape! Those were lost pictures, unfortunately.

So, today was busy for me and I only got a few things done on the Norge.

Got the compressor dome installed. I tried making a fiber gasket out of the same material as the headgaskets for the Frigidaire recip compressors. Unfortunately, it leaked horribly. I think the fiber material was too thin, and also the machined surfaces on the compressor are grooved. I think the original gasket must have been a special compound which would mash into the grooves and seal in them. The thin, hard fiber didn't work.  In the end, I used Permatex Right Stuff.

Now it holds vacuum!

I took some more pictures of the inside of the evaporator using a Harbor Freight borescope. Quality not so stellar, but you can get the picture that it's not too filthy after cleaning with degreaser.

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This is the return tube. The small cup at the end is the oil wicking device. See the metal mesh wicks on the side of it?

This cross-bar is the part of the float which connects to the needle valve.

Nov 9, 2018 4:18:40 GMT elec573 said:

Nice job with the new seals it’s probably better than new ! 

It amazing to me how your able to come up with fixes with old parts .  They seem like they are better than the original parts . 

Nov 9, 2018 5:13:32 GMT ckfan said:

Seeing you assemble this compressor really makes me appreciate just how well built they were. Very precise machining. Makes sense though. The meter misers were built with the same level of precise machining. I can also see why this would be an expensive machine to produce. Very neat stuff. Seeing inside of the evaporator is cool too. So the screen helps shoot the oil back to the compressor? I’m a little confused about that.

It is really precise. Nothing will fit together unless it's perfectly aligned. Even with just a coating of oil (not a constant supply) it has good compression... and that's after 80 years of use and abuse!

The materials are incredibly hard, as well. The shaft required a special carbide insert lathe tool. I tried with a cheaper carbide tool, and it would not produce an acceptable roundness or surface finish. The tool which finally did the job was a very keen, small pointed tool which just shaved a tiny sliver off at a time. It took quite a while to get that shaft trued up.

The oil wick is interesting for sure. It is supposed to "soak" the oil from the surface of the refrigerant and allow it to transfer over the top of the return cup, via capillary action. From there the suction of the return like will take it back to the compressor. It looks iffy at best to me. However, Frigidaire has noting at all in the evaporator for this feature, and they seem to work well without it. My 31 Frigidare has been in operation for several months now and it has not seemed to have any lost performance which could be due to oil logging in the evaporator. Travis's 1928 model is also working well and has not seemed to change at all since its first startup. I am using the same refrigerant and oil combination in the Norge. It should work even if the oil wicks are not doing anything, assuming the same dynamics are at play as in the Frigidiare evaporator.

If I have time, I may post a page from the Norge manual about the oil wicks tomorrow.

Nov 10, 2018 3:14:44 GMT elec573 said:

Very nice thanks for the updates like seeing your rebuilds !  It’s nice to see these old fridges brought back to life! 

Thanks! I enjoy the challenge as well. They will of course be higher maintenance than a hermetic unit; however that's just part of the way they were back in the day.

Today I opened up the motor and cleaned all the parts. The rotor is very heavy. I'm sure this is to help with smoothness of the unit by adding flywheel mass. The winding is in good shape. It's hard to kill a Delco motor!

Next, the start capacitor needed to be replaced. It was leaking and these "sardine can" capacitors are a very familiar failure point for the antique fans I also work on. That has to go.

It is an Aerovox, and still works. It just has some leakage on it.

Aerovox capacitor nameplate built into a rupture disc. This would pop open at the center before the capacitor could built up enough pressure to explode. Don't want anyone to lose an eye!

Gutted the capacitor and put a new Aervox cap in the housing.

Packed it with foam to ensure the cap doesn't move around and break.

Looks legit!

Motor leads re-insulated with heat shrink and new cap installed.

Motor is back on the unit!  The compressor does work, as well.

View of the assembly. I have a sight glass there, since we don't have a documented correct charge amount for this machine, running anything other than SO2.

Painted the compressor aluminum silver like it was from the factory.

And a short video!