Start trips breaker

[Hobbyman2]

I have a similar problem my motor runs fine with no belts. I have cleaned and oiled the Sheave and shaft on the motor and on speed control,
When I put the belts on and have it set to slow the motor Sheaves DO NOT open and the breaker trips. If I manually pull the motor Sheaves apart
it will run until the motor Sheaves start to close.
How do they open with that spring.
I have it plugged in a 20 AMP outlet that has nothing else attached to it
The belts are pliable.
I don't know what else to do.
Any help would be greatly appreciated

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https://www.youtube.com/watch?v=1HoUwYug-6k

[DLB]

...
[b]How do they open with that spring[/b].
...

Normally the motor sheaves open and close in response to the idler sheaves opening and closing, which is under the control of the speed control. As you decrease speed you close the control sheaves, increasing belt tension. The motor sheaves have the spring so they open in response to the increased tension, compressing the spring. Increasing speed, everything is opposite and the motor sheaves close in response to reduced belt tension allowing the spring to expand. The floating sheave on the motor simply moves to balance spring tension to belt tension.

From the description, your next step is to determine if something, like a bearing, is creating mechanical resistance that the motor cannot overcome. That can be anywhere from excessive drag to a seized bearing. IIWM I'd put a sanding disc on and just spin the headstock by hand. It does not take a lot of mechanical resistance to be a problem.

Note: We tend here to presume 'traditional' circuit breakers which provide over-current protection only. If yours are 'new fangled' that's something else to look into. Generally, Arc Fault and/or Ground Fault or any combination breakers may trip for reasons other than excessive current for excessive time.

- David

[BigSky]

...
[b]How do they open with that spring[/b].
...

Normally the motor sheaves open and close in response to the idler sheaves opening and closing, which is under the control of the speed control. As you decrease speed you close the control sheaves, increasing belt tension. The motor sheaves have the spring so they open in response to the increased tension, compressing the spring. Increasing speed, everything is opposite and the motor sheaves close in response to reduced belt tension allowing the spring to expand. The floating sheave on the motor simply moves to balance spring tension to belt tension.

From the description, your next step is to determine if something, like a bearing, is creating mechanical resistance that the motor cannot overcome. That can be anywhere from excessive drag to a seized bearing. IIWM I'd put a sanding disc on and just spin the headstock by hand. It does not take a lot of mechanical resistance to be a problem.

Note: We tend here to presume 'traditional' circuit breakers which provide over-current protection only. If yours are 'new fangled' that's something else to look into. Generally, Arc Fault and/or Ground Fault or any combination breakers may trip for reasons other than excessive current for excessive time.

- David

Does the belt tension actually change.

I think not because at the same time the motor pulley is reacting in equal but opposite manner.

The pulley ratio is changing but not the belt tension.

If the motor pulley does not respond properly (equal but opposite) belt tension most probably will change causing excessive load thus kicking the breaker. Lubricate the motor shaft and manually verify that the motor sheaver motors smoothly in both directions. When doing this manually avoid allowing the sheaves to slam together.

[Hobbyman2]

The OP mentioned this was a older unit, how about the cord ? any chance the cord may have a issue ? a few broken strands or a bad end ? jst tossing this out there .

[dusty]

I have a similar problem my motor runs fine with no belts. I have cleaned and oiled the Sheave and shaft on the motor and on speed control,
When I put the belts on and have it set to slow the motor Sheaves DO NOT open and the breaker trips. If I manually pull the motor Sheaves apart
it will run until the motor Sheaves start to close.
How do they open with that spring.
I have it plugged in a 20 AMP outlet that has nothing else attached to it
The belts are pliable.
I don't know what else to do.

Any help would be greatly appreciated

With the speed control set to slow, if the motor belt is installed, the motor sheaves (Fan and Floating) should be wide open. The motor belt riding at the outer edge of the upper (Idler and Control) sheaves.


?????If I manually pull the motor Sheaves apart it will run until the motor Sheaves start to close.????? How do you achieve this??

[DLB]

...
With the speed control set to slow, if the motor belt is installed, the motor sheaves should be wide open. The motor belt riding at the outer edge of the motor sheave.
...

Did you mean: motor belt riding near the outer edge of the idler sheave?

- David

[dusty]

...
With the speed control set to slow, if the motor belt is installed, the motor sheaves should be wide open. The motor belt riding at the outer edge of the motor sheave.
...

Did you mean: motor belt riding near the outer edge of the idler sheave?

- David

Thank you for correcting me. I did not say what I was thinking.

A picture may be more helpful:

Sheaves and Shaft a Comparison.jpg (163.37 KiB) Viewed 849 times

[dusty]

...
With the speed control set to slow, if the motor belt is installed, the motor sheaves should be wide open. The motor belt riding at the outer edge of the motor sheave.
...

Did you mean: motor belt riding near the outer edge of the idler sheave?

- David

See corrections to my previous post.

[DLB]

A picture may be more helpful:
Sheaves and Shaft a Comparison.jpg

Dusty - On a sample of one machine here, the sheaves move much more than your drawing depicts. I'm looking at the distance from the motor shaft washer to a point on the floating sheave, essentially the length of the spring at a given amount of compression. At high speed my machine matches the drawing, 2-5/8". But at low speed my machine is ~ 1/3/8" while the drawing shows 2-1/16". Sheave travel is over 2X compared to the drawing. I don't mean to nit-pick, the focus of this thread is low speed startup. As you said earlier: spring fully compressed and belt riding near the outer edge of the idler sheaves, that's when I'm getting the 1-3/8".

JACOBEIS - From your description it sounds like your machine may be indicating slow but the sheaves/belt are not actually in the slow position. That would be a different problem than most of this thread is talking about. Also a much simpler problem to diagnose and solve. Can you confirm?

- David

[dusty]

A picture may be more helpful:
Sheaves and Shaft a Comparison.jpg

Dusty - On a sample of one machine here, the sheaves move much more than your drawing depicts. I'm looking at the distance from the motor shaft washer to a point on the floating sheave, essentially the length of the spring at a given amount of compression. At high speed my machine matches the drawing, 2-5/8". But at low speed my machine is ~ 1/3/8" while the drawing shows 2-1/16". Sheave travel is over 2X compared to the drawing. I don't mean to nit-pick, the focus of this thread is low speed startup. As you said earlier: spring fully compressed and belt riding near the outer edge of the idler sheaves, that's when I'm getting the 1-3/8".

JACOBEIS - From your description it sounds like your machine may be indicating slow but the sheaves/belt are not actually in the slow position. That would be a different problem than most of this thread is talking about. Also a much simpler problem to diagnose and solve. Can you confirm?

- David

All I can offer in response is that this drawing depicts the measurements of one of my machines and nearly matches the other. In addition to that, I have a new motor with sheaves and the measurements there match the drawing.

How deep the belt moves down into the floating sheave is a function of belt dimensions. This would affect the sheave separation and thus the degree of spring compressions.

I have 1 1/2HP Emerson motors. The spring is retained on the shaft in slightly different manner on other machines. Might that contribute to the differences. Also. I measure from the face of the sheave to the inside of the washer - the the spring itself. That may explain. However, the delta between your measurements and mine appear to be greater that would would be caused by technique.

My sketch redrawn to match your dimensions. I'm without explanation! I cannot get that separation between the sheaves (1 3/4") even if I fully compress the spring.