|
Post by turbokinetic on Nov 23, 2018 0:58:31 GMT
That is so sad! Well, now we know for certain that it never stood a chance.
Yeah it is unfortunate. On the positive side, our group of hobbyists will learn a lot more about the CA because of it.
I think we need to bottle up the essence of it, and sell an exclusive perfume "Eau De Seeay" and tout the "alluring, smoky bacon overtones paired with just a hint of the fruity bouquet of Methyl Formate; augmented by the robust and bold aroma of burnt petroleum oil; finished by the romantic fragrance of wood smoke and charred organic, free-range cotton..." That would sell like hotcakes! I've been wearing it all day and the ladies have been swooning.... or maybe passing out from the fumes!
The windings. Where the winding turns were trapped in the stator core, there is still charred cotton in place.
This is the pressure relief valve. The oddly worn ring at the top is the seat of the valve spool. That is supposed to seat against a smooth surface. The gnarly looking ring-shaped groove in the plate is the mating wear mark. This relief valve was constantly chattering due to overpressure on the unit which caused this abnormal wear.
Compressor mechanism. A lot of very precise and complex machining went into this.
The relief valve spool and seat, after reconditioning. I think that yesterday, when I spun it with the drill, and seemed like it had low compression, this was probably why. I bet the relief was passing all the time.
All the parts fit and work like new.
The unloader. The round blob on the left end is melted solder. The motor got so hot while failing, that it melted the solder out of this. And it is not even touching the windings. It's an inch above the motor!
The assembly back together, without a winding.
The rotor is pressed on too far and it's below the stator core. My bad.
You can see the unloader orifice and valve spool tip in the larger, upper hole.
The valve spool is weighted, and the spring is an extension spring. It stretches and allows the valve spool to move and block the port. When the motor stops, it retracts the pintle of the valve spool back and opens the port.
In this video, I function test the unloader by spinning the compressor up with compressed air. You can hear the bypassing of the air being controlled by the unloader, based on RPM.
|
|
|
Post by birkie on Nov 23, 2018 3:37:50 GMT
Wow, what an educational excercise! On the one hand, it is an apt follow-up to the Westinghouse burnout experiment. On the other hand, many of the internal workings of the CA are explored.
Seeing the unloader work was downright fascinating, especially in the context of compressed air. While I still have yet to experience a CA firsthand, I did know they had a distinctive unloader sound. The video makes it clear what is happening.
The high pressure bypass valve was quite interesting as well. I did not know that something like that existed. So do I understand it correctly that it operates based on the differential between the high side and the low side? In any case, it seems like a unique source of rattle in the CAs.
All very interesting. Lots to digest. Thanks for taking the time to cut it open and document this!
By the way, I love the secret message passed between the assembly workers
|
|
|
Post by turbokinetic on Nov 23, 2018 4:04:27 GMT
Wow, what an educational excercise! On the one hand, it is an apt follow-up to the Westinghouse burnout experiment. On the other hand, many of the internal workings of the CA are explored. Seeing the unloader work was downright fascinating, especially in the context of compressed air. While I still have yet to experience a CA firsthand, I did know they had a distinctive unloader sound. The video makes it clear what is happening. The high pressure bypass valve was quite interesting as well. I did not know that something like that existed. So do I understand it correctly that it operates based on the differential between the high side and the low side? In any case, it seems like a unique source of rattle in the CAs. All very interesting. Lots to digest. Thanks for taking the time to cut it open and document this! By the way, I love the secret message passed between the assembly workers Aaron, you're very welcome. Any interest I can generate in these machines is a good thing, in my opinion!
You are absolutely correct about the pressure safety valve. If the pressure between the high side and the low side get too great; it will allow high pressure to return to the low side. It seems to have a strong spring. I did an experiment which I did not film. I wanted to "inert" the CA with the broken line with something that would not allow corrosion. I'm out of N2 so I used recovered R152A vapor. I ran the unit to circulate it, and was able to get a differential pressure of 50 PSIA between the low and high side, with no rattling and no apparent problems. At that pressure level, the motor current was nearing 5 amps, and the start relay tried to kick back in. I stopped at that point to avoid hurting the motor. I never heard the valve pop off with that test. It was, however, running with a high volume of gas flow - a lot of mass to compress - so the motor would see a heavy load. If the low side were in a high vacuum and the compressor was pumping only a small mass per revolution, I am sure it could develop a lot higher pressures before overloading the motor.
I emptied the oil out of the compressor dome, and got 6 cups! The oil seems very thick compared to regular compressor oil. I did a brief search about CA rotary compressor oil and couldn't find much about it. The GE manual doesn't mention it. Has anyone done an oil change on one of these? I was thinking it looked stringy, like oil with Lucas high viscosity additive mixed with it.
And yeah the secret message really is good to see. That's one of the reasons I love the antiques!
|
|
|
Post by birkie on Nov 23, 2018 14:23:25 GMT
The oil seems very thick compared to regular compressor oil. I did a brief search about CA rotary compressor oil and couldn't find much about it. The GE manual doesn't mention it. Has anyone done an oil change on one of these? I was thinking it looked stringy, like oil with Lucas high viscosity additive mixed with it. There is a thread that mentions oil viscosities, though not for the CA specifically: monitortop.freeforums.net/thread/886/general-electric-refrigeration-oilRotary compressors seemed to have recommendations in the 150-300 range, so it is plausible the CA had something closer to 300? It's odd that there isn't much specific information on the oil requirements. Even the Nickerson & Collins book is silent on viscosity, and mentions fill volume as the only concrete spec.
|
|
|
Post by ckfan on Nov 23, 2018 16:01:57 GMT
I’m not exactly sure what happens when oil gets overheated but is it safe to assume that this oil is not as it usually would be since it got so hot?
|
|
|
Post by turbokinetic on Nov 23, 2018 16:17:00 GMT
The oil seems very thick compared to regular compressor oil. I did a brief search about CA rotary compressor oil and couldn't find much about it. The GE manual doesn't mention it. Has anyone done an oil change on one of these? I was thinking it looked stringy, like oil with Lucas high viscosity additive mixed with it. There is a thread that mentions oil viscosities, though not for the CA specifically: monitortop.freeforums.net/thread/886/general-electric-refrigeration-oilRotary compressors seemed to have recommendations in the 150-300 range, so it is plausible the CA had something closer to 300? It's odd that there isn't much specific information on the oil requirements. Even the Nickerson & Collins book is silent on viscosity, and mentions fill volume as the only concrete spec. Hi Aaron, thanks for the article reference. It's sort of "expected" that no matter how common and mundane their oil actually is, manufacturers will claim it is special and specific and "use nothing else" yadda yadda yadda. It may help prevent mistakes by technicians when the units are common and routinely serviced, however, after the years go by; it makes restoration and hobbyists jobs much harder!
The Norge Rollator had what seemed like a heavier oil than the Frigidaire reciprocating compressors. The factory manual says it is specific to the Rollator compressor. I used 150 viscosity and it has been perfroming well. When I opened the Norge system and removed the old oil, it wasn't as thick as the oil from the CA. The weather also wasn't as cool during the time I repaired the Rollator.
I saved the CA oil, so maybe it can be analyzed.
With the CA, there was virtually no oil in the float chamber needle and seat area. Those parts were dry (and worn). I haven't tried pouring out the evaporator yet. When I removed the float seat, I found this "wire" sticking out of it. It's tiny, and looked like welding wire at first.
But, on closer inspection, it's actually a very tiny tube. The end was, of course, plugged off with some form of debris. I broke off a short piece to expose the opening you see below. There was no filter of any sort.
The seat is worn, however it's not visible in any pictures I took. Will have to try again today for pictures.
Needle tip is so-so but has some wear on it. Notice how dry all the parts are? No oil anywhere near it.
youtu.be/xq5FibbQHvA
My verbal explanation:
|
|
|
Post by turbokinetic on Nov 23, 2018 16:19:07 GMT
I’m not exactly sure what happens when oil gets overheated but is it safe to assume that this oil is not as it usually would be since it got so hot? It's very hard to say, due to the design of the compressor. The oil its self looks fine. Since the unit was not actually running when the burnout happened, it's likely the oil was sitting passively in the bottom of the compressor dome, and may have not been exposed to the full heat of the motor failure. The oil settled out and was clear after sitting overnight.
|
|
|
Post by ckfan on Nov 23, 2018 17:10:27 GMT
That little tube you found was introduced on the form B CAs. It was there to allow non condensable gasses to pass by the float! They had already recognized there was an issue by the time they released the form B.
|
|
|
Post by turbokinetic on Nov 23, 2018 18:00:37 GMT
That little tube you found was introduced on the form B CAs. It was there to allow non condensable gasses to pass by the float! They had already recognized there was an issue by the time they released the form B.
Cool. I sort of figured it was a Form B thing. Not sure if the manual we have on the site mentions internal differences between the A and B. It does show B specifications if I remember.
It's interesting for sure. So, it is as if the design was "growing a capillary tube" at that time already LOL! I see that the float wear, aggravated by a dry environment (oil staying in the compressor), and NCG's really all would be solved (or at least mitigated by) a capillary tube system. That's definitely the way to go, it seems.
I'm trying to think of a way to conceal the screen and cap tube inside the insulation space between the evaporator mounting plate and the compressor deck. I would want it to be concealed so that even by looking inside the cabinet, there isn't a visible modification (other than possibly a coupling or soldered joint where the unit was taken apart.
|
|
|
Post by Travis on Nov 23, 2018 18:10:30 GMT
I am glad to see someone dismantle some of these units that aren't viable anymore. This is that reason that Lou and I haven't called a scrapper to haul off some off this stuff.
Once it's gone there's no:
Restoration of the machines Parts for other machines Learning from the unit
I almost scrapped a DR2, but then I realized that I would like to open it and use it as a display.
|
|
|
Post by turbokinetic on Nov 23, 2018 20:35:20 GMT
I am glad to see someone dismantle some of these units that aren't viable anymore. This is that reason that Lou and I haven't called a scrapper to haul off some off this stuff. Once it's gone there's no: Restoration of the machines Parts for other machines Learning from the unit I almost scrapped a DR2, but then I realized that I would like to open it and use it as a display. This is why it's so important that some of us with space, keep up with these.
|
|
|
Post by elec573 on Nov 27, 2018 5:23:38 GMT
Thanks for the inward look at a ca ! I’m sure a lot of us old enthusiast appreciate it . I thought the unloader video was very good. I remember the small tube through the float from a previous post, we were not sure what it was for then .
To some one that’s just picked up an MT its probably more than they want to know. But for us enthusiasts it’s gold thanks !
|
|
|
Post by turbokinetic on Nov 27, 2018 15:13:52 GMT
Thanks for the inward look at a ca ! I’m sure a lot of us old enthusiast appreciate it . I thought the unloader video was very good. I remember the small tube through the float from a previous post, we were not sure what it was for then . To some one that’s just picked up an MT its probably more than they want to know. But for us enthusiasts it’s gold thanks ! Thanks! It's just in my nature to want to know and learn about things. As said in the video, probably that would bore most folks to tears, but there are a few of us who appreciate it!
|
|
|
Post by elec573 on Nov 28, 2018 2:46:38 GMT
There was some one looking for a needle and seat from a ca a while ago, an old post . I believe it was Chris don’t know if he still is looking but this should help out .
|
|
|
Post by turbokinetic on Nov 28, 2018 4:39:35 GMT
There was some one looking for a needle and seat from a ca a while ago, an old post . I believe it was Chris don’t know if he still is looking but this should help out .
Well, this one is pretty worn. I would be glad to give it to him, though. If this unit does get put back into service, it would be with a capillary tube.
|
|