Shopsmith Forums

Since we're talking about induction motors here, do you know if there's a way to determine the health of the windings by Ohming the input conductors? I'll be danged if I can visually find any issues with my motor and, since the windings show 0 potential to the case, how to make absolutely certain that there is indeed a fault??? I'm not too terrible an electrician but my motor theory seems pretty weak.

windy wrote:Since we're talking about induction motors here, do you know if there's a way to determine the health of the windings by Ohming the input conductors? I'll be danged if I can visually find any issues with my motor and, since the windings show 0 potential to the case, how to make absolutely certain that there is indeed a fault??? I'm not too terrible an electrician but my motor theory seems pretty weak.

You will need an ohm meter that can read the difference between a ground/short (0 ohms) and 1 ohm. The actual run windings should be from 1 to 3 ohms and the start windings from 2-5 ohms with no ground or short from either winding to the frame/ground. You should read between 1 to 3 ohms between the the 2 power leads. You can check the start windings by checking between the one of the capacitor leads and one of the power leads. You should get a 0 ohm reading between the other capacitor lead and the power leads. It may take several combinations of capacitor and power leads to read the start winding ohms. No shorts to the frame/ground at any time.

Last year my Sawsmith cord shorted out. thought it got the motor. But it did not. It burnt the cord & switch contacts. the switch still turned on and off looked good with my meter but would not start the motor.
I ended up replacing the capacitor cleaned the start run relay. wired around the switch & bad wire, did a test run, no smoke, checked the amps all was good.
I looked all over for the switch no luck. So I mounted a metal switch box with a heavy 20amp wall switch on top where the old switch holes where.Now it's back up and running. Hope this helps.
If you can find a mom & pop motor repair shop that can help. I was told the motor was proprietary and they could not find a replacement.
I would hang on to ALL old motors. if you have one that runs and you can afford it, take it to a motor repair shop have it dipped, baked & put new bearings on it.

Does anyone in this group know if Magna produced radial arm saws for Sears? The look very, very similar.

windy wrote:Does anyone in this group know if Magna produced radial arm saws for Sears? The look very, very similar.

Didn't see them on the list, but I've been told that I'm half blind...

http://vintagemachinery.org/Craftsman/m ... spx?sort=1