Shopsmith Forums

My Mark 5 has been working great until today. I used it last weekend. Went to use it today, and the motor just hummed.

This is what happened. My youngest daughter was in my shop with me and I was about to use the bandsaw. As I was setting up for that, she put on her safety gear (ear muffs and goggles). I was about to turn it on when I checked the speed setting and realized that the last time I used it I had left the speed set too fast for the bandsaw. I disconnected from the bandsaw, turned it on and slowed the speed down, turned it off and hooked the bandsaw back up. I put on my ear muffs, and right as I flipped the switch, my daughter said something to me. I flipped it back off and she repeated what she said. I turned it on again, and it just hummed (and sorta growled). No turning.

I started checking everything. Everything turned freely. I pulled off the belt cover and inspection hole cover. Everything looked fine. Tried different electrical outlets on different circuits. I put the sanding disc on, applied power and turned the disc by hand to give it a boost. No change.

I took the motor off the headstock and set it on a bench. Applied power and just a hum (and sort of a growl) and very slow turning of the shaft. The shaft feels fine when turning it by hand. The bearings feel fine and make no noise.

What did I do? Did the quick on/off fry something? It worked just before that.

Start switch/capacitor most likely.

The on/off might have placed the contacts in a position not normally taken.

The start switch fly weights etc. may be hung up.

Try gentle 'banging' to possibly free it.

From your description, I do not thing you have damaged it by the minimal attempts(short duration).

Which manufacturer?

Put the Shopsmith in the drill press position. I remove the belt housing off the headstock and use compressed air to blow all around the motor. I use a large rubber hammer and hit the motor pan a few times while blowing the air. The start winding contacts will get sawdust, belt dust and aluminum dust inside the motor that prevents the contacts from closing.

If this is unsuccessful, let us know as you may need to remove the motor and take some ohm readings. I have a rebuilt1 1/8 HP GE reversible motor available that I finish converting and rebuilding this week if all else fails. Contact me with Email if additional questions as I stock all the motor parts in house.

Success!

There wasn't really much sawdust in the motor pan and the motor didn't look dirty, and the vents weren't covered with sawdust. Between that, it working seconds earlier, and my ignorance with electric motors, I wasn't even thinking along simple terms. I've been worried about it all evening, fearing coils were burnt or something and wondering when I was going be able to afford a replacement motor.

When I hit the motor with some compressed air, I was surprised with how much dust blew out of the vents! I followed the advice and tapped it pretty good with a rubber mallet while blowing compressed air through it until dust stopped coming out. When I plugged it back in, it purred along just perfectly!

Thanks so much!

heathicus wrote:My Mark 5 has been working great until today. I used it last weekend. Went to use it today, and the motor just hummed.

You could have just gotten the right sheet music, so it wouldn't have to hum. (Sorry, had to go there!)

Glad it was an easy fix!

steve

skou wrote:You could have just gotten the right sheet music, so it wouldn't have to hum. (Sorry, had to go there!)

Glad it was an easy fix!

steve

And the growling?



Maybe rock!:eek:

I typically approach such problems with a blinding flash of profanity and name calling (be sure the shop is empty first ) then grab a mallet and make sure the thing is awake. Only then do you attempt any kind of testing.
Since you had humming and growling (are you sure that the growling wasn't you? ) you already knew that you had power to the motor. Otherwise just start at the beginning. That is usually the outlet, then the plug, then the cord, then the switch and so on...
One thing I keep pushing is that if you think it is the capacitor you are most likely wrong. Yes they do fail but not nearly as often as guys like to think. Never doubt the capacitor until you have checked the starter switch.


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[quote="robinson46176"]I typically approach such problems with a blinding flash of profanity and name calling (be sure the shop is empty first ]

But...But growling and humming sorta indicate that we have power. Therefore, the breaker is not tripped, the cord and connector is not our problem. What is left. Something is in a bind or the start capacitor is not doing its' job which is likely the fault of the centrifugal switch.

robinson46176 wrote: . . . Otherwise just start at the beginning. That is usually the outlet, then the plug, then the cord, then the switch and so on...
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Important word!!!!!;)