Trying to get an old band-saw working

[Corrie]

I know nothing about this thing, can't even find the model anywhere:
**broken link removed**

Smoke was pouring out the old capacitor (start / run, I'm not sure) was a 60-80uF 275v, replaced with an 80uF 400v. Now smoke coming out of the motor...

**broken link removed**

*Think* that little black box is a magnetic cutoff operated by the magnetic field of the motor to isolate the capacitor and start coils (on the side its got "B8475/1 Magnetic Devices Limited England"). So assuming this is the case i thought the bearings were impeding the speed needed to cut out the starter coil and causing it to overheat.. replaced bearings.

I'm now in the predicament of not wanting to let any more smoke out of the motor, but i don't know how to test the alleged magnetic cut off. I need to wire up something to tell me if there is electricity flowing through those blue wires, so i can turn the thing on and maybe give it a ten count and if the electricity flow isn't interrupted i can switch it back off without damaging the motor further and investigate the black box (maybe using a separate switch to bypass it) i don't know how to go about this test safely though.


Anyway, thought it was time to get some advice, any help would be very welcome.

Thanks.

 

[cowboybob]

Welcome to ETO, Corrie.

You could try this method: http://www.akamaiuniversity.us/PJST9_2_324.pdf

However, it seems that O L Smith, Ltd., is no longer in business. And no google hits for "B8475/1 Magnetic Devices Limited England".

And judging from the condition of their Manuf. plate, your band saw (and its components) is pretty old. And at this point the motor's windings have been seriously overheated (and not for the first time, would be my assumption). Finally, trying to suss out the starter cap's cut-out switch and its operation would be largely guess work.

For all that, I'd advise getting a new motor (with centrifugal starter cap cut-out). All other efforts would cost as much (most notably, new windings and some sort of motor starter arrangement) would probably cost more than a simple replacement motor.

 

[Corrie]

cowboybob - If new windings are needed i will take your advice and just get another motor (even though fitting it will be no cake walk). But I'm not convinced the main windings are shot yet, the starter /auxiliary winding maybe is not in good shape but they are not so important (would just take longer to power up). The actual main windings might just be ok, and i already have a foot-switch that could replace the magnetic cut off if it came to that .. so still just need to test the cutoff.. thinking a volt-meter from the top-left terminal on the picture, across to the negative wire coming from the main switch, if no one comes in with another suggestion i will try that tonight.

 

[cowboybob]

Worth a shot. Let us know how it goes.

 

[MaxHeadRoom78]

You can obtain new Potential relay from any winding shop.
One way to test the motor without start cap is to give the shaft a sharp spin as possible at switch on, the motor will normally run up to speed.
It will run in either direction with this method.
Max.