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Post by Travis on Aug 6, 2016 3:28:09 GMT
I think it's half-ass running on the run winding. I thought it was running on the start winding, but after it continued to run after I insulated the start contacts it made me wonder. The paragraph under the DR3 and 4 description of the operation states the capacitor is in series with the start winding. I was hoping the capacitor had opened and that would explain the lack of power to the shunt and series coils. I believe the series coil might be energized, but you need the shunt coil to force the arm up.
I could be all wrong. I have tried for years to understand the operation of these.
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Post by coldspaces on Aug 6, 2016 3:52:05 GMT
I think it's half-ass running on the run winding. I thought it was running on the start winding, but after it continued to run after I insulated the start contacts it made me wonder. The paragraph under the DR3 and 4 description of the operation states the capacitor is in series with the start winding. I was hoping the capacitor had opened and that would explain the lack of power to the shunt and series coils. I believe the series coil might be energized, but you need the shunt coil to force the arm up. I could be all wrong. I have tried for years to understand the operation of these. That might just be right. I am not sure just what an open or shorted capacitor would to to the shunt coil forces.
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Post by ckfan on Aug 6, 2016 15:54:09 GMT
We can only hope it is a capacitor. I told my friend drew about this and he shook his head. He is currently without AC because his condenser fan motor capacitor blew. He told me that the situation sounded familiar!
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Post by Travis on Aug 6, 2016 22:03:13 GMT
I did temporarily replace the block with a pair of capacitors last night. Unfortunately, there was no change in operation. I will try and remove the control and inspect connections, measure motor leads and attempt to start it with the annie. I am not sure when this will happen. I have the DRF4 on a dolly close by and can't move it myself. I don't want it to slip off the dolly. Maybe the guys that deliver the DR4 on Monday will help. Then again, after they deliver, they might be mad and want to get the hell out. It's a shame that so few people find moving these majestic appliances to be fun.
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Post by Travis on Aug 8, 2016 2:54:02 GMT
I did lift the control. Everything looks fine. I disconnected the motor leads and check resistance. They had been: 2.9 ohm run to common, 5.4 ohm start to common and 7.9 ohm run to start. They now are 2.3 run to common, 3.3 start to common and 2.9 ohm run to start.
I had 31 kohm between any motor lead and ground originally. Now I have 2-3 ohms.
The good thing is that this is a bolted dome unit!
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Post by coldspaces on Aug 8, 2016 4:52:48 GMT
Oh no! Guess the cotton gave out. Bolted dome does it least make it doable mechanically, financially ouch!
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Post by ckfan on Aug 8, 2016 15:23:08 GMT
I did lift the control. Everything looks fine. I disconnected the motor leads and check resistance. They had been: 2.9 ohm run to common, 5.4 ohm start to common and 7.9 ohm run to start. They now are 2.3 run to common, 3.3 start to common and 2.9 ohm run to start. I had 31 kohm between any motor lead and ground originally. Now I have 2-3 ohms. The good thing is that this is a bolted dome unit! Wow, that is the most positive thing I've heard in a long while. I'm sorry that it is for sure dead. But, as you said, it is a bolted dome so it isn't completely done for!
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Post by coldspaces on Aug 12, 2018 13:55:31 GMT
Travis recently requested I get the windings out of this unit so we can send two stators in at once for rewinding. After the so2 was gone and evacuated for hours I shut the purge screw and let it sit under vacuum all night. Then pulled another vacuum. And still it stinks after setting with nitrogen inside. Oh well most of it was gone and I could open it without having to leave the garage. This is a factory rebuilt unit. Friday night I took a look in side and found extra wood blocks had been left inside and used as wedges and misc. rubber grommet, washer and cork washers. DR35 (2) I was going to unbraze the lines near the evaps but decided I would not get the plate above the evaps off of the suction line unless I cut it above the plate. I also decided to cut the line from the float and straighten it some, will use an elbow to put it back together. That liquid line was very hard to bend and I had to carefully used a tube bender to help get it straight enough. DR35 Now I set the top down on its edge on 3 layers of cardboard and rolled it over upside down. At this point I cut the condenser line near the float while using nitrogen to help blow out the chips. DR35 (3) Now it was time to open her up. The bolts were extremely tight on this compressor. I don't know if the factory was trying to make the original lead seal hold or what but it took a breaker bar to get some of them lose. After tapping off the mounting ring I found that this base is not drilled and tapped to use bolts to push her open. Also can't put long bolts in the holes to make temporary legs. DR35 (4)DR35 (5) After getting it pried open the first thing that caught my eye was the trash on the terminal. Also some lose in the oil that looks to clean and clear to believe. DR35 (6) DR35 (7) DR35 (8)Here we have the oil sump (hanging upside down) Best I can tell the famous black crud some how has been collecting under the heater and congealed together. It then must have came lose and moved around. If I take a sample and rub in between my fingers it crumbles into smaller back pieces with no noticeable fibers from cloth windings that I could see. DR35 (9)Although this terminal was starting to short out with crud and its fiber washer was bad a quick scrap out and flush of the crud shows it has 1 million ohms to groung with the bad windings disconnected. I think it will be ok after a proper cleaning. DR35 (10) DR35 (13) Rotor is nice. DR35 (11) And finally the stator with its bad windings. DR35 (12)
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Post by ckfan on Aug 12, 2018 15:04:11 GMT
Damn, that looks pretty gnarly. It really makes me wonder where all of this black crud is coming from. It honestly makes me wonder if it is soot left over from brazing lines without nitrogen in them. I know that is a long shot for this much crud but it still makes me wonder if a lot of systems from this vintage have the same crud inside. It really makes me wonder.
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Post by coldspaces on Aug 12, 2018 17:12:46 GMT
I have never seen it all built up under the heater like this, need to see if it works and how many watts it is.
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Post by birkie on Aug 12, 2018 18:20:42 GMT
I have never seen it all built up under the heater like this, need to see if it works and how many watts it is. I just showed the pictures to the kids while stopping for lunch on the long drive home. Their verdict: "eeeeeewwwww". Which terminal is that? The carbon by the heater is also a bit concerning. I've always had a fear that keeping it plugged in too long (days? Months?) without the machine running could cause the oil to scorch around the heater. Despite the ickiness of the carbon crud on the interior, I love seeing pics of DRs opened up. Thanks for sharing!
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Post by turbokinetic on Aug 12, 2018 19:47:35 GMT
Travis recently requested I get the windings out of this unit so we can send two stators in at once for rewinding. ..... After getting it pried open the first thing that caught my eye was the trash on the terminal. Also some lose in the oil that looks to clean and clear to believe. DR35 (6) DR35 (7) DR35 (8)Here we have the oil sump (hanging upside down) Best I can tell the famous black crud some how has been collecting under the heater and congealed together. It then must have came lose and moved around. If I take a sample and rub in between my fingers it crumbles into smaller back pieces with no noticeable fibers from cloth windings that I could see. DR35 (9)Although this terminal was starting to short out with crud and its fiber washer was bad a quick scrap out and flush of the crud shows it has 1 million ohms to groung with the bad windings disconnected. I think it will be ok after a proper cleaning. Thanks for sharing the pictures of this repair! Love seeing how these have faired over the years, inside their sealed home. That one terminal really is odd. It's as if the black crust on the terminal caused a short to ground, and this lead to a cascading failure.
Did you have a chance to measure resistance of that terminal alone, WITH the crud, but without the winding connected? How about just measuring the crud by its self? A chunk of it between meter probe tips?
It's interesting to me, seeing as how the SO2 Westinghouse units also seem to go to ground at the terminals.
Again I really appreciate your taking extra time during this repair to document it. Makes it so much more rewarding to participate here.
Damn, that looks pretty gnarly. It really makes me wonder where all of this black crud is coming from. It honestly makes me wonder if it is soot left over from brazing lines without nitrogen in them. I know that is a long shot for this much crud but it still makes me wonder if a lot of systems from this vintage have the same crud inside. It really makes me wonder. I have a theory. This is just something that comes to mind but I have not had an opportunity to see the black crud in person, so this is just for opinions. The low side of a SO2 system runs at less than atmospheric pressure. This makes these units susceptible to taking on air during operation. Air would contain some moisture and oxygen. If it was in the fridge cabinet where the seeping was happening, it could draw in a lot of moisture from the frost and sweating of the lines.
My theory is, that over time, through seepage, air and moisture enter the system. The SO2 dissolves in the water forming sulfurous acid. The acid, or acid + oxygen (possibly) are going to react with "something" in the system. Black crud makes me thing some sort of carbon compound is being formed. Oil has a huge amount of carbon tied up in its molecules. The winding insulation made of cotton also has carbon in it. The crud seems to form around hot areas, such as the heater well, terminals (maybe a loose / hot connection?) and on the winding its self. Many chemical reactions only happen above certain temperatures.
I wonder if the cotton is being slowly broken down, causing the crud to form, and also eventually leading to insulation failure? Or, if the crud is forming from carbon taken out of the oil, but the crud its self is electrically conductive - and when it deposits on the winding it causes resistive shorts that eventually fail the winding?
Again these are just musings from someone who has some education but not any experience with the crud in question. I won't be upset if someone tells me this is nuttery I am speaking LOL!
I have never seen it all built up under the heater like this, need to see if it works and how many watts it is. I just showed the pictures to the kids while stopping for lunch on the long drive home. Their verdict: "eeeeeewwwww". Which terminal is that? The carbon by the heater is also a bit concerning. I've always had a fear that keeping it plugged in too long (days? Months?) without the machine running could cause the oil to scorch around the heater. Despite the ickiness of the carbon crud on the interior, I love seeing pics of DRs opened up. Thanks for sharing!
You got to love how kids describe things!
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Post by Travis on Aug 12, 2018 22:07:34 GMT
The heater was working and was around 18 watts.
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