10ER motor spins both ways

[don1357]

I have been rebuilding a 10ER and today I got to replace the original wire. Now when I power it the motor works, but every once in a while it will spin in the opposite direction. If I start spinning it before powering up it maintains that rotational direction. I can see how this could come handy but right now I would like to fix this.

[chapmanruss]

don1357,

I really don't have an answer as to why that is happening and not a problem I have experienced. I have replaced the power cords going to many motors used on Model 10E and 10ER Shopsmith tools I have restored. Mostly doing it to replace cracked insulation and dangerous cords. A plus is giving the tool a ground wire. After about 70 years of use it is not surprising that they need the cords replaced. Some of the motors have terminals to connect the power cord to while others are spliced together to the motor's wire leads. Having it reverse direction periodically sounds like a different problem than wiring it incorrectly. Right now, my best suggestion would be to make sure the motor is clear of all dust and check that all contacts are clean. Maybe a shorting connection on a contact is causing the problem but I am not an expert on electric motors so just a guess.

[JPG]

I be guessing here (this is a most unusual experience)

1) the motor has a natural tendency to start in one direction when the start circuit is ineffective.(a logical conclusion given the problem)

2) that natural tendency reverses occasionally due to factor(s) unknown.

3) by placing the motor in rotation prior to energizing, forces that tendency in the direction already moving.


I think a close examination of the start circuit(start winding, start capacitor, start switch) will reveal the cause.

[don1357]

It seems to also be a capacitor issue, or partially a capacitor issue. It would work and spin as described with the motor free spinning, as in not mounted with the belt and in the machine. Once mounted it doesn't have enough initial strength to overcome the friction. It may be fixable but as luck would have it I have a spare motor laying around :-\

[JPG]

Continuity check the start switch and connecting wires. An interesting 'test' would be to remove the capacitor from the start circuit and try the free spinning test. I predict no difference.