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Post by Penguin45 on May 16, 2014 19:38:33 GMT
I love my air compressor. It's a monstrous great old Thorite with a 150L receiver and a big single pot pump on top belt driven by a large squirrel motor. I did a few jobs today and headed out to the garage, to be greeted by the horrible smell of burnt electrics and a humming noise from the compressor. It's a capacitor start, capacitor run motor, so I removed the cover of the motor wiring box, hoping that I'd find the rating..........  Oh dear......... charcoal. Poking about with the test meter revealed that the start winding in the motor has gone anyway, so new motor required. The motor has no rating plate, and the specification sheet was stuck to the inside of the lid of the wiring box, which went up in smoke. Given the size of the motor and the fact that it will run on a 13amp supply, I think it's a 3hp motor. The question is, will it be 2 pole (2,800 rpm) or 4 pole (1,400 rpm)? I can find nothing at all to enlighten me - help! Chris. |
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Post by dave1800 on May 17, 2014 2:17:45 GMT
Oh dear what a mess. Not something I have had any experience other than fixing a well pump in the garden here which is rated at 1HP output but consumed 1KW (75% efficient). Is there enough left and access to the guts of the motor to try and count the number of poles? It may be worth looking at similar size compressors to see what they use. I would have thought 3 HP output is pushing it for a 13amp plug/fuse on the basis that 3HP = 2250 watts but allowing for inefficiencies like my well pump say 2800 watts consumed which is 12 amps and more of course on start up. However, just to add to the confusion I found here when trying to source a new motor that some quote the HP as input power and others as output; I'm not sure how the rating is identified in the UK. As far as the speed is concerned can you recall what it sounded like, maybe have a video somewhere? Regards David I love my air compressor. It's a monstrous great old Thorite with a 150L receiver and a big single pot pump on top belt driven by a large squirrel motor. I did a few jobs today and headed out to the garage, to be greeted by the horrible smell of burnt electrics and a humming noise from the compressor. It's a capacitor start, capacitor run motor, so I removed the cover of the motor wiring box, hoping that I'd find the rating.......... Oh dear......... charcoal. Poking about with the test meter revealed that the start winding in the motor has gone anyway, so new motor required. The motor has no rating plate, and the specification sheet was stuck to the inside of the lid of the wiring box, which went up in smoke. Given the size of the motor and the fact that it will run on a 13amp supply, I think it's a 3hp motor. The question is, will it be 2 pole (2,800 rpm) or 4 pole (1,400 rpm)? I can find nothing at all to enlighten me - help! Chris. |
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Post by Penguin45 on May 17, 2014 18:10:31 GMT
A picture speaks a thousand words. Was I scared? Of course I was..........  Chris. |
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Post by dave1800 on May 18, 2014 0:22:01 GMT
Maybe worth keeping a stock of 13Amp fuses handy and checking the socket doesn't get too hot especially if it's old and a bit sloppy. Good to see it's up and running again. Was it a very expensive repair? David A picture speaks a thousand words. Was I scared? Of course I was.......... Chris. |
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