Can Increasing a Spool's Diameter Boost a Motor's RPM?

In summary: If you have a circular saw, you could probably do this with a bit of care. Alternatively, you could try finding a different type of motor with gearing that would be more suitable for your needs. Thanks for your question!
  • #1
jsmith24
3
0
Hi all,

I have a small DC motor which turns at 20 rpm. The shaft diameter is 6mm, giving a circumference of 18.85 mm. What I want to do is get an effective rate of 30 rpm. Can I do this by simply attaching a spool or spindle to the motor output shaft with a larger diameter? If so, would it be as simple as increasing the diameter by a factor of 1.5?

Thanks,
Jack
 
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  • #2
20 rpm! That was not much. Is a gear built-in the motor? Can you change the gear?

But yes: Increasing the diameter of the pulley, you will speed up the velocity of the belt.

Other possibility: Increase the voltage to the motor.
 
  • #3
Yes, it's a geared motor, sorry! High torque. I'm limited to 12 volts DC, so that's out. I thought it was as simple as increasing the diameter of the shaft (pulley), which would increase the circumference, thereby moving more belt per revolution, effectively increasing the rpm. Thanks!

Jack
 
  • #4
jsmith24 said:
Yes, it's a geared motor, sorry! High torque. I'm limited to 12 volts DC, so that's out. I thought it was as simple as increasing the diameter of the shaft (pulley), which would increase the circumference, thereby moving more belt per revolution, effectively increasing the rpm. Thanks!

Jack

By increasing the diameter of the pulley (on the motor axis), you are mechanically gearing up the motor. An alternative is to decrease the diameter of the pulley on the load.
 
  • #5
There's no pulley on the load. It's a simple guillotine-style door. The motor will have a spindle on it, a cord attached to the spindle which will wind up when the motor is forward energized, which, in turn, raises a flat door in a track. When the motor is reverse energized, the spindle reverses, the cord unwinds, the door descends. The problem is that I find 20 rpm (or rather, the amount of cord travel per revolution) too slow. As this was the only motor I found handy, I'm trying to make do. The motor already has plenty of torque to raise the door (which is rather light), so gearing up a bit shouldn't be an issue.

Oh! I forgot to answer part of your question: No, I don't think I can change the internal gearing of the motor.

Thanks!
 
  • #6
Well, then just increase the diameter of the spool as you suggested in #1.
 

Related to Can Increasing a Spool's Diameter Boost a Motor's RPM?

1. How does a motor rotate?

A motor rotates by converting electrical energy into mechanical energy. This is done through the use of an electromagnetic field, which causes the motor's rotor to spin.

2. How does a pulley affect motor rotation?

A pulley can be used to change the direction of motor rotation. By attaching the motor to a pulley system, the motor's rotational motion can be used to drive other components or objects.

3. What is the purpose of a pulley in a motor?

The purpose of a pulley in a motor is to provide mechanical advantage, allowing the motor to exert more force or torque on the object it is driving. This can be useful in situations where the motor needs to lift heavy objects or overcome resistance.

4. How do you determine the speed of motor rotation?

The speed of motor rotation is determined by the frequency of the electrical current supplied to the motor. The higher the frequency, the faster the motor will rotate.

5. Can a motor rotation be reversed?

Yes, a motor rotation can be reversed by changing the direction of the electrical current supplied to the motor. This can be done by switching the polarity of the power source or using a motor controller to change the direction of the current flow.

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