View Full Version : Speed Control -- Question
"...the unit will run approximatly 20-30 seconds before tripping the
breaker..."
Strongly suspect motor problems. Sounds like the starting windings aren't kicking out and the motor is continuing to draw its start-up amps. Suggest you have it looked at by someone who knows his way around the inside of an electrical motor.
With all good wishes,
billmayo
08-09-2008, 07:20 PM
I have just repair 3 different headstocks in a row with a similar problem. The front motor bearing (behind the sheave) had seized (spun inside the end housing) or was about to seize (unable to turn bearing by hand). Only the seized bearing was making a loud squealing noise. Each of the headstocks did trip the breaker quickly. These were the first motor bearing problems that I have found since I begin working with Shopsmiths many years ago. When I disconnected the motor belt, it was difficult to turn the motor sheaves.
However, this problem does sound like the start windings never disconnected. I have not seen the start winding contact points stick together on a Shopsmith. I do find some burned points that will not conduct electric to the start windings. You will get a hum from the motor when this occurs.
Thanks for the replys :) .....
Nick....belts are ok.....unit does run smoothly when turned it by hand....
the unit will run approximatly 20-30 seconds before tripping the
breaker...
a1gutterman
08-09-2008, 09:16 PM
Bill, on those units with that particular bearing problem, can you tell where the bearings were made?
wood4me
08-09-2008, 11:27 PM
i took the drive belt off and the motor ran smoothly this evening ( a good thing i think ).... thinking of cleaning / repairing / replacing the quadrant assembly ???? hopefully in that order...
THANKS for being patient with me:)
p.s. if the assembly is "stuck" at a high r.p.m. could that be cause the tripping of the breaker:confused:
a1gutterman
08-09-2008, 11:42 PM
If you have a cord that is small guage wire and are operating on a 15 amp circuit, it is definitely possible that if you are starting at high speed, you may trip the breaker. Especially if you have any kind of load on any of the drive shafts.
termite06
08-10-2008, 03:27 AM
I noticed the other day when slowing the ss, there is a loud click around "O". Is this normal? I think it used to do this the first few months too.
nuhobby
08-10-2008, 04:31 PM
Yes, that sounds normal. That might even be "proof" that your anti-rattle spring is still properly present behind the dial. There is a depth change in the relief sections behind the dial, that is encountered by that spring when you're winding down from high speed.
billmayo
08-10-2008, 07:34 PM
They were the original NSK from Japan that Shopsmith used. What I found was caked sawdust againest the front bearing in each motor that was oil soaked. These are metal shielded bearings so I believe the sawdust wicked the oil from the bearing causing the problem. If the sawdust in the headstock was blown out once in a while, I do not believe this problem will occur. The bearings on the opposite end was only a little worn. I am using rubber sealed bearings (2R) on both motor ends to prevent this problem.
Bill, on those units with that particular bearing problem, can you tell where the bearings were made?