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Post by allan on Nov 4, 2013 1:54:27 GMT
Excellent pics. Very well built. Mild steel is very compatible with S02 but unfortunately this one had moisture problems in system it looks like. The black sooty stuff in the float chamber seems to be the same looking stuff that I have run into on these. It eventually restricts the seat. On DR's a restricted seat means motor winding failure to follow, if unit isn't serviced. John how involved is a rewind on a DR? Have you had it done and if so what cost? What type magnet wire do you have to use to be so2 compatible?
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Post by jhigdon2 on Nov 4, 2013 2:41:15 GMT
Winding job not hard. Just have to select winding materials based upon what refrigerant you plan to use. If unit is going to be refilled with S02 and kept original. Use PTFE wire with twisted glass tie cord and wood or bakelite wedges. standard paper can be used to line the stator wireways. A good quality 18 ga. lead wire with a strand count in the 70's or higher. These 3 lead wires also must have the glass fiber insulation. Using these materials eliminates the chemical reactions that were the downfall of the original wood and cotton windings. The only drawback is $$$. Teflon wire very pricey. Option 2 Do a standard rewind that is suitable for hermetic installations using modern refrigerants. To do this is much simpler and cheaper. Rewind using amide immide wire. After rewinding they are dipped in epoxy and baked. These are extremely reliable and half the price of the Teflon route. Option 3 search the whole world trying to find double cotton wrapped winding wire. LOL
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Post by coldspaces on Nov 4, 2013 4:49:51 GMT
Great pics of the float, thanks for posting.
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Post by allan on Nov 4, 2013 16:52:42 GMT
Winding job not hard. Just have to select winding materials based upon what refrigerant you plan to use. If unit is going to be refilled with S02 and kept original. Use PTFE wire with twisted glass tie cord and wood or bakelite wedges. standard paper can be used to line the stator wireways. A good quality 18 ga. lead wire with a strand count in the 70's or higher. These 3 lead wires also must have the glass fiber insulation. Using these materials eliminates the chemical reactions that were the downfall of the original wood and cotton windings. The only drawback is $$$. Teflon wire very pricey. Option 2 Do a standard rewind that is suitable for hermetic installations using modern refrigerants. To do this is much simpler and cheaper. Rewind using amide immide wire. After rewinding they are dipped in epoxy and baked. These are extremely reliable and half the price of the Teflon route. Option 3 search the whole world trying to find double cotton wrapped winding wire. LOL If you were going to go to the trouble of a rewire what gas would you select to use for the best overall reliability??
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Post by jhigdon2 on Nov 4, 2013 20:14:31 GMT
If I do another winding job I would select R134 and shave the piston. Or maybe R600? as cablehack has sugjested. These modern amide imide winding jobs are extremely good and will stand up to any modern refrigerant. Most winding shops have no trouble rewinding these stators to modern hermetic specs. Cotton windings only had a 105c rating. amide imide has much much higher temp performance.
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Post by jhigdon2 on Nov 5, 2013 3:13:13 GMT
Oh I forgot to mention price for rewinding. It's been a couple of years ,but I woud plan on spending in the niehborhood of 400-500 for a good quality hermetic stator rewind. Double the cost for a teflon job. I have used Eurton electric in California for a few of them . I had Palo alto electric do a rewind on one using teflon windings. I have a stator out of a DR2 that is freshly rewound at Eurton that I havn't used yet. I will take a pick of it and post it in a day or so. On the flickr site in my photo's there is a picture of a teflon wound stator that I used on a DR3.
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Post by allan on Nov 5, 2013 14:22:21 GMT
See my comment on this seat under GE in film
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Post by allan on Nov 5, 2013 19:34:24 GMT
For the record and future DR orfice cleaning this seat orfice is a #60 wire size or .0400 inch opening. This will allow cleaning without scratching or distorting the hole
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Post by allan on Nov 6, 2013 0:56:44 GMT
Resized images Attachments:
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Post by allan on Nov 6, 2013 1:01:59 GMT
Here is the DR opened up. Oil was still golden in color and compressor was locked up. Disassembled and found piston seized in the cylinder. Removed piston from cylinder with a wood block and rubber mallet, then hooked up motor and ran the motor with no piston attached. Crank bearings seem good and piston and cylinder are black but metal looks good. I bet it ran cold with no heater and had no oil in the pump. Thinking about cleaning piston and cylinder with rubbing compound to get it clean and sliding again, any comments??
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Post by jhigdon2 on Nov 6, 2013 5:07:57 GMT
Wow. Don't look real bad. Seized up problem is familiar. Also when somebody turns one of these over oil sump gets flooded with S02 then if turned on before the heater has a chance to drive it out. S02 gets sucked up into oil pump instead of oil. Piston always is the first part that seizes. If it's not to scared up they usually polish out just fine.
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Post by allan on Nov 6, 2013 10:44:54 GMT
Wow. Don't look real bad. Seized up problem is familiar. Also when somebody turns one of these over oil sump gets flooded with S02 then if turned on before the heater has a chance to drive it out. S02 gets sucked up into oil pump instead of oil. Piston always is the first part that seizes. If it's not to scared up they usually polish out just fine. Remarkably I find no signs of scarring on any of the moving parts! Thinking maybe I can clean up and run with the dome off and oil in the sump to see how it acts, what do you think? This project is to learn more about the DR compressor for future service wisdom. After inspecting this thing inside and out I still can not understand what causes them to make the noises I have heard come from mine that are running and working, any ideas about that? What would be the best way to polish the piston and cylinder? I had thought about simple automotive finish polishing compound
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Post by jhigdon2 on Nov 8, 2013 7:50:05 GMT
Great! I use scotch brite or 1000 grit sand paper or both to polish the piston and cyl. After inspection of the other components I rinse everything with starting fluid and reassemble. These have more moving parts than the CK and others. They also have very close tolerances on all those parts and if any are slightly worn then I guess that could create noise. I have seen the rod brgs get a little loose on a couple of them. I have never seen a DR that is completely quiet at all times. Generally they are very very quiet machines but if overcharged or in initial cool down or heating element bad or just plain worn a little they will rattle a little. After reassembly you can mount it back in the base and screw in the 4 bolts that were used to press the can off to make a nice little stand. Put enough oil in sump to cover oil screen and turn it on and watch it run.You can hook gauges up und see if it will pull a 28-29" vacuum. It's really interesting bench testing these. You can see the oil circuit working and be amazed at the precision and balance. If it pulls a good vacuum, it should be a candidate for service again if desired.
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Post by allan on Nov 8, 2013 10:59:21 GMT
Great! I use scotch brite or 1000 grit sand paper or both to polish the piston and cyl. After inspection of the other components I rinse everything with starting fluid and reassemble. These have more moving parts than the CK and others. They also have very close tolerances on all those parts and if any are slightly worn then I guess that could create noise. I have seen the rod brgs get a little loose on a couple of them. I have never seen a DR that is completely quiet at all times. Generally they are very very quiet machines but if overcharged or in initial cool down or heating element bad or just plain worn a little they will rattle a little. After reassembly you can mount it back in the base and screw in the 4 bolts that were used to press the can off to make a nice little stand. Put enough oil in sump to cover oil screen and turn it on and watch it run.You can hook gauges up und see if it will pull a 28-29" vacuum. It's really interesting bench testing these. You can see the oil circuit working and be amazed at the precision and balance. If it pulls a good vacuum, it should be a candidate for service again if desired. Glad to hear you had ran a DR open! Amazingly I see very little wear and all bearings seem tight. This one was stuck due to the ultra hard black residue that was on the surfaces that seemed to be lacking proper lube. I cleaned off the black stuff with my Harley Davidson chrome cleaner which worked very well. As far as I can tell it did not alter the metal at all but removed the black stuff. Close inspection shows very minor ultra small metal pitting on the piston but again it is so small and just on a very little area. Temporary reassembly reveals that you can spin everything very easy with the valve head off and everything seems tight. The crank bearings have no detectable side to side play and seem great. Motor starts right up and runs good with compressor detached. Common to run is about 3.2 ohms and common to start reads about 4.7 ohms. Start to run measures 7.9 ohms and I read 360K ohms from each leg to the case. This is with the windings literally saturated and dripping with oil. Definitely no plans to reassemble this one for permanent use as this was sacrificed to my gain of knowledge which has proven to be a good idea. I understand so much clearer now how the DR works and maybe some of these parts can help a future project
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Post by jhigdon2 on Nov 13, 2013 2:37:44 GMT
Here's a fresh stator for a DR2 rewound to modern hermetic specs. Attachments:
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