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Post by honestcharlie56 on Jun 16, 2020 3:51:01 GMT
Good Evening,
I have a 1950 Frigidaire with an 1/8 HP Meter Miser. I just picked up the fridge yesterday and got to cleaning it up and working on it today. After replacing some wiring I went to start going through some functional performance checks. I rewired the compressor exactly as it was. I believe it was still factory wiring, because it had the ring terminals tinned into the compressor lead wires as to properly fit the meter miser terminals. After working through some bugs in the YT relay we achieved a start and run. The only problem being the run lasted all of 2-3 seconds. I bypassed the YT relay for testing purposes, to see if the high current draw was due to the compressor sitting for an extended period. The current draw on the compressor started at about 12 amps and slowly started dropping. It didn't drop fast enough for my liking so the test was abandoned. Can anyone point me in the right direction to save this fridge?
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Post by CCL2F2 on Jun 17, 2020 12:10:26 GMT
“ I bypassed the YT relay for testing purposes” did you disconnect the start winding once it started?
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Post by honestcharlie56 on Jun 17, 2020 20:22:12 GMT
Yes, for the test I have a plug with a switch. The plug is wired to the compressor and I have a single lead running to what I believe is start. I'll hold the start lead to the hot for less than a second to get the compressor started. Once started I removed the start lead from the hot. I have it wired up as Common/Start/Motor looking at the compressor from left to right. I determined this via original wiring removal and testing the resistance across the terminals.
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Post by honestcharlie56 on Jun 17, 2020 20:24:00 GMT
I attempted to let it run alittle longer than the first test yesterday. I wanted to go around the system with a heat gun and see if I had an internal blockage somewhere. I didn't notice any change in amp draw. If you let it run long enough that compressor housing does get quite hot and eventually the compressor will stall.
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Post by jake on Jun 19, 2020 1:18:21 GMT
Welcome to the forum! I have two 1950 Frigidaire DM-90P refrigerators. Sounds like you have the wiring correct. From left to right, looking at the compressor,you have common, start, and run. The center, start terminal,should be connected to the right, run terminal, for a second or two to achieve start up. Then the start terminal should be removed from the circuit for the rest of that run cycle. The refrigeration system in these is such that it can take up to about 45 minutes before any cooling and frosting is noticed in the freezer if the fridge has been sitting unused for a long time. Are you seeing any cooling or hearing any bubbling sounds in the freezer? If, after confirming you have the wiring correct, it still will only run a few minutes and the compressor stalls it sounds like you may have a blockage or air in the refrigeration system.
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Post by honestcharlie56 on Jun 19, 2020 3:24:41 GMT
Jake,
Thanks for the welcome! I'm glad I found this place! I've learned so much just from reading threads as a guest. I would love to swap pics of your fridges, PM me if you want. It starts cooling instantly. Within seconds of a successful compressor start I can hear liquid boiling in the evaporator. A few more seconds later and the evaporator is cold to the touch and begins to sweat ( I'm in Texas, so it doesnt take much for vapor to condense on a surface here just FYI). The only issue is the super high compressor amp draw. I'm measuring amp draw with a Fluke 57-V that was originally purchased with NIST cert and I built our calibration verification lab at work which verifies the instruments calibration yearly. Long story short, I kinda trust the meter. "you may have a blockage or air in the refrigeration system", so admittedly I'm not the sharpest tool in the shed......I've had the pleasure of working with some incredibly intelligent people, I'm just not one of them! That being said, if I had a blockage in the lines anywhere would I have a significant pressure temperature drop at that point? I've been over the circuit (short of the circuit concealed in the cabinet) and found gradual temperature decline in the condenser. Could the cap tube have a decent enough restriction to inhibit performance yet not show it externally?
My main question is what could possibly load this 1/8 HP compressor enough for it to draw 12 amps.
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Post by jake on Jun 19, 2020 4:25:41 GMT
Hmmmmm, it sounds like, from your readings of 12 amps on 120 volts, that the compressor is running on the start winding. The 12 amps would convert to about 1400 watts which is about normal for the starting wattage. The exact specs for starting wattage is between 1800 to 2200 watts at ambient temperature of 70°F and between 1900 and 2400 watts at ambient temperature of 90°F, depending on your model. My Frigidaires run at about 1500 starting watts, 114 running watts, and around 1.9 amps. Since you have cooling I'm leaning towards an electrical problem. Try this, use a test cord and wire it directly to the compressor. Attach the white wire from the cord to the left terminal of the compressor. Attach the black wire to the right terminal of the compressor. Connect a short piece of wire from the center, start, terminal of the compressor to the right, black wire, terminal and plug it in. As soon as the compressor starts pull the start wire off the black wire terminal and see how the compressor runs. Monitor the current draw of the compressor. If it's now normal and you have good cooling, you have a wiring problem. Remember that by doing this the compressor will not shut down if it gets into trouble or when the freezer gets down to temperature. So don't leave it running this way unattended! Please post back with your findings!
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Post by honestcharlie56 on Jun 19, 2020 14:55:57 GMT
Jake,
Thanks for the response. That is how I have the compressor wired as we speak. Its wired directly to a plug and I'm using a jumper on the center terminal (assuming start). I touch the jumper (from center) to hot on the plug to start the compressor and then remove it. If you try to run the compressor on just far right terminal and the far left, it will just hum....as expected. A quick contact of the center terminal starts the compressor right up. I'll get some amp draw readings with start connected too and see what I get.
I don't mind recovering the refrigerant and changing the oil, I just want to make sure I'm not missing something before I go through the trouble. I didn't bother before hand because all three terminals are dry so no evidence of the common leaking there, no oil on any lines anywhere and finally when started I can hear refrigerant in the evaporator....so I just assumed I still had a sealed system.
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Post by CCL2f2 on Jun 23, 2020 6:31:50 GMT
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Post by honestcharlie56 on Jun 23, 2020 14:04:46 GMT
Thanks for the link. I do have a meter miser pulled apart on the bench right now, it came out of what I think is a 1947 Frigidaire. I'll start another thread on it soon enough.
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Post by turbokinetic on Jun 27, 2020 23:25:23 GMT
Jake, Thanks for the response. That is how I have the compressor wired as we speak. Its wired directly to a plug and I'm using a jumper on the center terminal (assuming start). I touch the jumper (from center) to hot on the plug to start the compressor and then remove it. If you try to run the compressor on just far right terminal and the far left, it will just hum....as expected. A quick contact of the center terminal starts the compressor right up. I'll get some amp draw readings with start connected too and see what I get. I don't mind recovering the refrigerant and changing the oil, I just want to make sure I'm not missing something before I go through the trouble. I didn't bother before hand because all three terminals are dry so no evidence of the common leaking there, no oil on any lines anywhere and finally when started I can hear refrigerant in the evaporator....so I just assumed I still had a sealed system. It sounds to me as if there is damage to the compressor winding. Your test with the plug connected to the left and right terminals, and the center being used as start is correct. The reason I expect there is damage is because, even running with start and run at the same time; the current draw would not be as high as you are seeing. I have pressured these up until they stall - with a good motor winding. The compressor will stall before the current reaches 6 amps, and then go to about 9 or 10 after the stall. Drawing 12 amps while it is running bodes very badly for it. What are the resistances between start, run, and common? And resistance to ground? |
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Post by honestcharlie56 on Jul 6, 2020 20:15:43 GMT
It sounds to me as if there is damage to the compressor winding. Your test with the plug connected to the left and right terminals, and the center being used as start is correct. The reason I expect there is damage is because, even running with start and run at the same time; the current draw would not be as high as you are seeing. I have pressured these up until they stall - with a good motor winding. The compressor will stall before the current reaches 6 amps, and then go to about 9 or 10 after the stall. Drawing 12 amps while it is running bodes very badly for it. What are the resistances between start, run, and common? And resistance to ground? Well it obviously was bad for it, I tried to restart it the other day and it will no longer start. I bought a 47' and this 50' on the same day, I just knew at least one would be a runner LOL. So I'm in the market for a 1/8 hp meter miser and a 1/9 hp meter miser. I would like to get both running as I hate to see things go to waste. I did get the 1/9 hp compressor apart and it had a very bad burnout. The 1/8 hp I still need to cut apart. |
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Post by turbokinetic on Jul 6, 2020 20:23:57 GMT
It sounds to me as if there is damage to the compressor winding. Your test with the plug connected to the left and right terminals, and the center being used as start is correct. The reason I expect there is damage is because, even running with start and run at the same time; the current draw would not be as high as you are seeing. I have pressured these up until they stall - with a good motor winding. The compressor will stall before the current reaches 6 amps, and then go to about 9 or 10 after the stall. Drawing 12 amps while it is running bodes very badly for it. What are the resistances between start, run, and common? And resistance to ground? Well it obviously was bad for it, I tried to restart it the other day and it will no longer start. I bought a 47' and this 50' on the same day, I just knew at least one would be a runner LOL. So I'm in the market for a 1/8 hp meter miser and a 1/9 hp meter miser. I would like to get both running as I hate to see things go to waste. I did get the 1/9 hp compressor apart and it had a very bad burnout. The 1/8 hp I still need to cut apart. Often times the relay stops working correctly; and cycles on the overload until that welds up and then the compressor goes up in smoke. That or people allow the wiring to crumble and short out at the relay, bypassing everything and causing the same sort of failure. Compressors are hard to come by, if you are wanting to keep it original. I've had fridges here for a year or more when the owner wanted to go back original and I had to locate a good correct one. Did you cut the compressor open in such a way that it can be re-welded? Could send the stator off for a rewind. Sincerely, David |
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Post by honestcharlie56 on Jul 7, 2020 2:38:19 GMT
David,
Thank your for your responses and your videos! Keeping it original would be ideal, but not a drop dead necessity. I cut it apart as neatly as I could, which took about 1.5 hours of an oscillating tool cutting just above the parting line of the body. I'm fairly confident I can re weld with the tig or mig. I'm having trouble getting the motor side out of the compressor body. Should I go ahead and start the new thread for the 47'? I need to get some pictures up so these are at least mildly appealing threads. Thank you everyone so far.
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Post by turbokinetic on Jul 7, 2020 13:21:21 GMT
David, Thank your for your responses and your videos! Keeping it original would be ideal, but not a drop dead necessity. I cut it apart as neatly as I could, which took about 1.5 hours of an oscillating tool cutting just above the parting line of the body. I'm fairly confident I can re weld with the tig or mig. I'm having trouble getting the motor side out of the compressor body. Should I go ahead and start the new thread for the 47'? I need to get some pictures up so these are at least mildly appealing threads. Thank you everyone so far. I've only ever opened up a very early one of these, which had a different seam design, along the bottom. Sadly, not familiar with opening the later ones. If i were you, I would start a fresh thread for the 47. |
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