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Post by coldspaces on Dec 16, 2019 3:58:26 GMT
Did you happen to figure out the cause of death for this dr . Sense you have it open and the winding out . Was it in your opinion just decaying of the cotton windings ? Or do you think it was a combination of deterioration of the cotton insulation plus the so2 combined. If this is the case all drs are going to fail at some point . For the same reason . Things were too rotten to try to find the short. Moving the windings caused too may bare spots to tell what was first. I would think the so2 would make things worse than say R12. Don't think I have taken apart any R12 compressors with cotton covered windings to know it it was better for the cotton. This one could have just been neglected and allowed to over heat. We have read that the cotton insulation will release water when it degrades. Of all the shorted Monitor Tops I have opened I have found very little corrosion. Plenty of black crud in most but things were not rusting away on the inside. I can't see where much water is produced just from bad winings. I would say they are all getting old and I bet the guys that built them would be surprised how may still work.
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Post by turbokinetic on Dec 16, 2019 10:08:30 GMT
I don't know how many different cotton-covered magnet wire suppliers existed in the early days, so this could be different. But; here is a 1937 Frigidaire unit, which has lived its life in R114 until last year. No sign of deterioration, and nothing is brittle. I bet you've seen these pictures before but if not, I put them here. More pictures here: monitortop.freeforums.net/post/25858/thread I know it's not as old, maybe 8 - 10 years newer. But, once you get up in the 80's years old maybe that's not all that significant LOL! This one is the unit which is now running R1234ZE for testing, by the way. Sincerely, David
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Post by ckfan on Dec 16, 2019 14:27:30 GMT
Yes, as David’s meter miser shows, I think that a combination of SO2 and heat are the main culprits here. I would say that either or might not be enough to cause the damage. I know for a fact that those meter misers run pretty hot almost every cycle. They are a high side dome just like the DRs and CAs and I would argue that they run hotter than a DR does. Another thing to consider is how many CAs we’ve seen with shorted windings. Almost none. The one David opened up is the only one I know of and we know that one was severely abused.
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Post by coldspaces on Dec 16, 2019 16:59:47 GMT
It looks like those winding were dipped in something or are they just oily? They do look real good.
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Post by turbokinetic on Dec 16, 2019 17:24:44 GMT
It looks like those winding were dipped in something or are they just oily? They do look real good. On the Meter-Miser they were really oily. I had to leave the parts sitting for months while at work; and left the housing upside down with oil in it. I had just poured it out before those pictures were taken.
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Post by Travis on Dec 16, 2019 17:34:28 GMT
Those windings do look good. I have no doubt the constant bathing of so2 is a problem in addition to the high side dome.
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Post by turbokinetic on Dec 16, 2019 17:50:47 GMT
Those windings do look good. I have no doubt the constant bathing of so2 is a problem in addition to the high side dome. True. Another one to think about - we have used borescope cameras on CA's which were seized up. The windings in them look like-new (similar to meter-miser picture above) in spite of all the years of use and abuse of the seize-up prone CA compressor. The Meter-Miser, CA, and DR are all HS dome.
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Post by coldspaces on Dec 17, 2019 0:19:37 GMT
More supplies that came last week. My coil winding board. Complete with winder than has a counter, coil forms, wire un-spooler with hose clamp tensioner and horizontally adjustable wire guide in the center. I think I covered everything it needs. Now I need to get back to making the slot insulation.
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Post by turbokinetic on Dec 17, 2019 0:23:57 GMT
More supplies that came last week. My coil winding board. Complete with winder than has a counter, coil forms, wire un-spooler with hose clamp tensioner and horizontally adjustable wire guide in the center. I think I covered everything it needs. Now I need to get back to making the slot insulation.
Looks like Santa Claus came early!
I was thinking.... have you considered converting this to a bolted type housing? I don't know if there is room, but you could attach a flange to the parting line and use bolts to draw it together. It would be easier to use for a test-bed if that were done. Just a thought and may be totally not feasible.
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Post by coldspaces on Dec 17, 2019 0:37:33 GMT
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Post by turbokinetic on Dec 17, 2019 0:51:20 GMT
Such good info there! Love seeing how they documented things back in the day. Now it's all secret.
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Post by gman1969 on Dec 17, 2019 1:46:16 GMT
Thanks so much for posting this. I've enjoyed reading through it for the last hour.
Gary
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Post by coldspaces on Dec 17, 2019 2:37:10 GMT
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Post by coldspaces on Dec 17, 2019 3:10:57 GMT
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Post by coldspaces on Dec 19, 2019 3:31:21 GMT
Although I wish I had Travis's unit back together I am sure glad right now its not. Never having rewound a motor before I don't know things like I should. I was worried about how squared off the old windings were. But I can look at the one done for Travis and see it must not mater as the shop that rewound it used rounded ends. Also nice to see just how they did the slot insulation. I made the slot insulation 1/4" longer than the stator on each end, like Travis's was. Each piece of slot insulation is 2&1/4" long x 1 & 24/32" wide. Back of slot was marked and bent at 5/16" wide. A few went in the trash and a few got trimmed down to fit after folding, sides were a bit long. First part of slot insulation is done.
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