Spin a big and heavy disc

Hi guys,

I’m facing a problem here and I’m not so experienced in working with motors and drivers. My only experiences are with little vibration motors, motorized faders, steppers and little more. I work with Arduino.

Now I’m working on a project where I need to spin a big wood disc. I don’t need to make it spin fast, in fact it will be suffient to accelerate it reaching a frequency of 1 complete round every 2/3 secs.

I’ve made experiments with a EMG49 motor and a Pololu High-Power motor driver 24v23 CS.

I’ve powered the driver with a 12V power supply able to feed 10A and I was perfectly able to make a little prototipal disc (diameter 70cm and a weight of 8kg approx) accelerate, spin and decelerate very well, even if I was driving the motor at half of its voltage and also with a little duty cycle PWM.

The definitive disc has a mass of approximatively 16 Kg with a 110 cm diameter.

Do you think it will be possible for the same motor/driver configuration to move the definitive wood disk?

In case not, would you be so kind to link me some motors and drivers with these capabilities (it should be relatively easy to connect it to and Arduino).
What are the physical characteristics I have to look for? What the calculations I have to do?

Thank you so much for your support


It would likely still work, but your top speed will be slower and your motor will be less responsive to acceleration/deceleration. You should check the current your motor will draw as well, and make sure its not too high; we typically recommend limiting continuous current to 25% or less of the stall current. If you notice your motor is drawing more than that, you might consider using a higher gear ratio of that motor, which will also have the effect of lowering the top speed, but improving the responsiveness.


Thank you @TonyP for your reply.
When you say

you might consider using a higher gear ratio of that motor

are you referring to the gearbox reduction ratio?
Is there any product on Pololu catalog witch can do for me (EMG49 is fine because it also has an encoder)?

Thank you so much

Yes, when I say gear ratio I am referring to the gearbox reduction ratio. The gearbox on the EMG49 is probably pretty close to the ideal gear ratio for using that particular motor in your application, given that your target speed is about 90 RPM and the no-load speed of the EMG49 is 143 RPM at 24 V. For other options, you could look at our 37D gearmotors with encoders, although please note that they are probably significantly lower power motors than the EMG49.

One possible issue you might face is whether the motor shaft can handle the load, if it is supporting the entire disc; if that is a concern, you could consider some other mounting options (such as having a motor turn a wheel or a gear that engages with the disc at or near the rim).

There is also one correction to what I said earlier; since your motor specs include a rated current, you should make sure it does not draw more than that in continuous operation, instead of the 25% I stated earlier.


The same question was answered here https://forum.arduino.cc/index.php?topic=633276.0
in part, but the OP did not seem interested.

Do you need “fine positioning” for the big wooden disk, or just “on/off”?
Since your speed requirement is “slow” but your mass requirement is “High”, gearing down the motors output shaft sounds like a good solution.

No matter what you do, you should use a “driver” to control a big inductive load, between the arduino and the motor. If you just need “on/off” a relay/contactor/MOSFET can be used to control power to the motor.