Humming

[sawchain]

I was wondering if anyone has sent there motor to Shopsmith to get a new capacitor replaced, according to the manual. I have a model 510,and today I was working on some pens,I went to turn it on and all it did was hum!! Or can I take it to a electrial repair shop and get it repaired. Thanks

[dusty]

Any good motor shop can help. Ask them to just bench test it. They'll tell you whether or not they can fix it.

Before doing that though, I would suggest that you first run a test of your own. Take the motor drive belt off the pulley and turn the Shopsmith on. Does it run or does it just hum?

If it runs - we got more work to do. We're waiting to hear what you find.

[sawchain]

I took the motor out and tested it on the bench and all it did was hum. So I think it should go to the repair shop.
Thanks, Fred

[dusty]

I took the motor out and tested it on the bench and all it did was hum. So I think it should go to the repair shop.
Thanks, Fred

I would normally say at this point that things are looking up. The circuit breaker did not pop as soon as you applied power; the motor just hummed.

In the past, I would then immediately conclude that the starting capacitor needed to be changed and I would have been very comfortable with that diagnosis. However, it has been reported here on the forum that the starting capacitor is seldom the cause so now I must wait and see.

The bearings could be seized but I would bet that you would have reported that as one of your symptoms and I doubt that the bearings are the cause of your initially reported problem. At this point in the process though, I would recommend that you seriously consider having the bearings replaced while the motor is at the repair shop.

Good luck and I am anxiously awaiting the results of your trip to the motor shop.

When you go to put it all back together, inspect the drive belt.

With the motor out of the way I would put that puppy up in the drill press mode where you can see and clean the daylights out of everything in the headstock.

Lubricate the threads on the headstock lock rod. I use graphite but there are other opinions about what to use.

Inspect the wedge locks for signs of serious wear.

Lubricate the sheaves real good. You seldom get this good a look at the insides of the headstock.

Take a good look at the speed control mechanism. You are looking for anything that is excessively worn, loose or bent.

When you put this all back together, you want to feel comfortable that you know the exact condition of everything in the headstock.

[JPG]

Have you checked to see if capacitor has become disconnected/broken wire/???

[billmayo]

I took the motor out and tested it on the bench and all it did was hum. So I think it should go to the repair shop.
Thanks, Fred

With the motor out of the motor pan, blow all the sawdust you can from inside the motor. I have not found a bad capacitor so far but found many motors that hums. I find that sawdust/crud collects on the centrifugal start winding contact points to where they no longer make contact. Sometimes, just banging on the motor casing will dislodge enough sawdust/crud for the motor to work again. However, I always file the contact points with a points file (fine grit sandpaper, nail file, emery cloth works too) to remove the burnt area on the points. An ohm meter can be used to show if the contact points are open as they should always be closed when not operating.

[robinson46176]

With the motor out of the motor pan, blow all the sawdust you can from inside the motor. I have not found a bad capacitor so far but found many motors that hums. I find that sawdust/crud collects on the centrifugal start winding contact points to where they no longer make contact. Sometimes, just banging on the motor casing will dislodge enough sawdust/crud for the motor to work again. However, I always file the contact points with a points file (fine grit sandpaper, nail file, emery cloth works too) to remove the burnt area on the points. An ohm meter can be used to show if the contact points are open as they should always be closed when not operating.

I was going to make this very post but had to leave for a few hours. "Always start at the beginning" and the capacitor is not the beginning. They do fail but it is really fairly rare. Fewer fail than most guys think because if a guy carts his motor into many electric motor shops and says it may be the capacitor then there is a good chance he will be sold a capacitor... Sadly I know a lot of tradesmen that will be happy to clean the contacts and add a new capacitor to the bill. I don't know why so many want to jump in and blame the poor helpless capacitor first. Maybe it is just that more guys can spell capacitor than can spell centrifugal...
With all of the motors I have used over the many years here on the farm I believe I have only replaced 2 capacitors. One on a 3' high pressure blower on a grain bin (when it was only 30 years old) and one on my farm shop air compressor that will barely start up at freezing temps and then only starts under great stress.