Just to set the record straight, rebuilding a fractional horsepower motor
can be done but is usually considered "beyond economical repair" for anything less than about 10 horsepower. With that said, there are a number of things the "non-electrical" troubleshooter can do to check and/or correct problems that can return a fractional horsepower motor to service. Oh, and by the way, 1998 is not old. Old would be 1970 or more. I came along in 1950,
that's old.
First things first: The smell of a burned motor, even if it burned 5 years ago, is unique to motors, coils, things of that nature. If you have ever smelled one, the smell is
unmistakable and you would never forget it. If it doesn't smell burnt, it's time to troubleshoot for other problems.
Assuming a metal cutting band-saw, it probably had OEM a capacitor motor. A small wood cutting band-saw may well have a split phase motor. I put one on a table saw a while back. It works well enough, but most of the stuff I do is light. The point being that it
may not be the original motor. It should be a four pole motor, just under 1800 RPM, 1745 or so.
As advised above, look to the capacitor first. It's cheap and easy to fix. The nameplate should have the size printed on it, but sadly this isn't done. When you find the right size, scratch it on the surface somewhere. You
will lose the note eventually, mark it on the motor.
Next, also mentioned above, look at the centrifugal switch. This is a bear to get back together right, and varies from motor to motor. Usually, it will be on the inside of the electrical end of the motor. Opposite the drive end.
Not always, but usually. Pull the end bell of the motor,
carefully because parts of the switch may be mounted to the end bell.
In my experience (50+yrs) the best contact dresser is currency paper, a dollar bill. The newer the better. If you
must file the contacts, use a fine or very fine cut, no sharp edges, and finish with currency paper. If they were silver plated, avoid filing them,
period, unless
absolutely necessary.
Also check the switch for operating at speed, 1/3 to 1/2 base speed. It should open freely and close when stopping. Just spinning the rotor by hand is not enough, but it does need to operate freely while checking.
And, of course, check the internal wiring for crimps, loose insulation, broken wires, broken insulation, and such. Carefully reinstall the end bell, watching for wires interfering with the switch mechanism. Reinstalling the end bell may require some fiddling. Tighten all the bolts and spin the motor by hand. Adjust tighter or looser till the motor spins the "free"est. Using a rubber hammer to "set" everything will help immensly. A chunk of 2X4 will do in a pinch, but nothing harder.
Spool the motor up, and on power off listen for the centrifugal switch closing. It will be a slight click as the rotor slows. If it doesn't come up to speed right off, you didn't get the wires clear of the switch. Take it apart and do so. Again and again, until it's right.
Not very likely, but
there is a possibility someone mounted a series universal or straight D-C motor. Again, not very likely, but a consideration. Look for the brush holders along the outside of the motor. Anything smaller than a couple of HP will have visible brush holders. Beyond making sure the brushes make up good on the commutator, you're on your own with those. I will not, under any circumstances, attempt to troubleshoot one remotely.
Bill Hudson
I know they should be on a "lump" on the side of the motor, but mine doesn't have that. I've also taken off the end caps and didn't see anything that looks like them. I do know what capacitors are, and I assume this motor has them (how the heck else does it start?). It's why I'm looking for a how-to somewhere. I can post a bunch of pictures if someone is willing to take a look at them, though!
