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Post by turbokinetic on Sept 15, 2021 17:25:34 GMT
It would be something like that, or the spring tension. The 58X121 relay fitted to 60 cycle CA form B machines is also known as the type E3, which is described in the Scotch Yoke manual on page 70. It was also used in the LK Lift Top. The adjustment is for pulling in at 6A and dropping out with a minimum of 5A. Presumably, if the horizontally mounted 58X14 from a CA form A was used a replacement, it should work provided it was adjusted to those currents. If a non standard relay is used or modified, it would be wise to check it over a range of line voltages just to make sure it's working correctly. It would be a real shame to burn out a motor because the start winding didn't disconnect. Good points. It's important for sure. I use a variac and some load resistors to test actual performance of the relay "on the bench" with an amp meter. Then use it to test the compressor with the relay at its full range of starting voltages. I believe the Monitor Top is designed to function from 90 to 130V, so using the variac, it should start successfully and release the start winding at any voltage within that range.
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Post by tommya11en on Sept 17, 2021 0:18:52 GMT
yes, you would have to be careful with it, i have no idea what the capability oh the coil is but exagerate it and say the coil can move 5 pounds and the contact weighs 5 ounces, chances are it would work just fine. have you noticed on these relays that it is actually pushing the contacts outward (or upward ) depending on the mounting position ?
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Post by cablehack on Sept 17, 2021 0:42:06 GMT
yes, you would have to be careful with it, i have no idea what the capability oh the coil is but exagerate it and say the coil can move 5 pounds and the contact weighs 5 ounces, chances are it would work just fine. have you noticed on these relays that it is actually pushing the contacts outward (or upward ) depending on the mounting position ? The relay works on the repulsion principle, where the armature is forms a shorted turn. Current flowing in the armature causes an opposite magnetic field to that in the coil, and thus repels it. It's not just a matter of the relay pulling in when power is first applied; it has to disengage when the current falls to a certain level.
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Post by tommya11en on Sept 17, 2021 1:51:07 GMT
yes, you would have to be careful with it, i have no idea what the capability oh the coil is but exagerate it and say the coil can move 5 pounds and the contact weighs 5 ounces, chances are it would work just fine. have you noticed on these relays that it is actually pushing the contacts outward (or upward ) depending on the mounting position ? The relay works on the repulsion principle, where the armature is forms a shorted turn. Current flowing in the armature causes an opposite magnetic field to that in the coil, and thus repels it. It's not just a matter of the relay pulling in when power is first applied; it has to disengage when the current falls to a certain level.
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Post by tommya11en on Sept 17, 2021 1:59:18 GMT
Obviously your a theoretical scientist. Do you assume that these relays follow science thruout there life. Is there some compensation for wear in your theoretical understanding of these relays or is there no wiggle room for the position change for normal wear calculated into the design ? If not they would probably have to be replaced every year or two. These units are pretty robust and residential to ware so they must have designed some room for deviation from the science or they would all be dead by now.
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Post by tommya11en on Sept 17, 2021 2:17:25 GMT
I will explore getting the shelves re-plated in zinc locally. I had the shelves re-plated in zinc for both my CA's back in 2013. They have lasted very well with no visible deterioration. I can't remember how much it cost, but I didn't think it was expensive at the time. It was done by an old fashioned electroplating shop near where I used to work.
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Post by tommya11en on Sept 17, 2021 2:18:04 GMT
I will explore getting the shelves re-plated in zinc locally. I had the shelves re-plated in zinc for both my CA's back in 2013. They have lasted very well with no visible deterioration. I can't remember how much it cost, but I didn't think it was expensive at the time. It was done by an old fashioned electroplating shop near where I used to work.
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Post by tommya11en on Sept 17, 2021 2:22:14 GMT
Did you have them hot dipped galvanized or electrolysis? I rebuilt a wind mill a few years ago and had all the pieces hot dipped. They were beautiful until the first rain. They turned dull but still beating mother nature. Do you know when GE started using Chrome plating on parts ?
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Post by tommya11en on Sept 17, 2021 12:42:36 GMT
it would be great if someone with the right equipment would test a 58X121 in both positions to actually see how much difference the mounting position changes the amperage when it kicks out.
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Post by turbokinetic on Sept 17, 2021 13:26:49 GMT
it would be great if someone with the right equipment would test a 58X121 in both positions to actually see how much difference the mounting position changes the amperage when it kicks out. I have the equipment and can do this test next time I have time off work. I've planned to do the same test with the three most common GE relays we see, in each position (correct position, left side up, right side up, front up, back up, upside down) and compare.
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Post by tommya11en on Sept 17, 2021 16:42:20 GMT
That will be interesting. Please post your findings.
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Post by cablehack on Sept 18, 2021 0:45:36 GMT
Obviously your a theoretical scientist. Just an electrical engineer. The adjustment of the relays is not super critical, such as within 100mA or something like that, since they wouldn't be able to accomodate a range of line voltages and contact wear. I've never had to adjust either of mine, despite the CA-1's relay having quite pitted contacts. My assumption is that the specifications which are given in the manual would more than likely be a mean value to suit the 90-130V operating voltage.
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Post by turbokinetic on Sept 18, 2021 11:26:27 GMT
Obviously your a theoretical scientist. Just an electrical engineer. The adjustment of the relays is not super critical, such as within 100mA or something like that, since they wouldn't be able to accomodate a range of line voltages and contact wear. I've never had to adjust either of mine, despite the CA-1's relay having quite pitted contacts. My assumption is that the specifications which are given in the manual would more than likely be a mean value to suit the 90-130V operating voltage. Yep. If the relay is adjusted correctly, the compressor will start (and the start-winding will disengage) at any voltage from 90V to 130V. The test has to be executed correctly as well because the power supply has to provide 90V under load at compressor starting conditions as well as 130V under running condition with both start and run winding engaged. That ensures that both ends of the range will be successful. I've fixed a few relays on fridges which had been previously worked on and now were inconsistent in operation. Previously; someone had bent the contact arm or made other modifications to the relay as a get-by fix. When originally tested, starting was possible at 118V or higher, but below that, no start. It was just on the threshold of the mains voltage supply and therefore it was a crapshoot whether or not it started. So if you repair the relay you need to test it properly, in the correct position, under the range of voltages for which it's rated. Otherwise there's no guarantee it will function correctly in the real world. But yeah, cablehack; you're right that wear and pitting of the contacts shouldn't affect the pickup and dropout current. That is, until the contacts are totally gone and the relay stops working.
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Post by redtangox on Sept 18, 2021 12:11:32 GMT
I’m constantly amazed at the collective knowledge of this group.
Reading threads like this are a highlight in my day and absolutely fascinating to me.
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Post by tommya11en on Sept 19, 2021 0:16:55 GMT
Haha well joneske was my Obi-Wan Kenobi. If someone finds a CA type A relay, they’ll be my Yoda.
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