Help choosing a suitable motor for my project

Help & Support Robot Parts
1

Hi all,

I wonder if someone can point me n the right direction for choosing a suitable motor. I am looking for either a DC or AC motor with around 100rpm and a torque of around 3-5nm minimum. I’m not sure if I should be looking for a geared motor, stepper motor etc? It needs to be small and compact, ideally max 50mm x 50mm x 120mm length.

I want to use it to lift a mill head up and down on my combination hobby mill/lathe. I have seen someone do this mod with a power window motor which worked very well BUT the power window motor drive shaft is at 90 degrees to the motor and I would like the drive shaft to be inline with the motor so I can install the motor inside the mill head. I believe this would be called a Planetary gearbox??

Any help would be much appreciated as I am a complete novice when it comes to electrical motors.

Thanks Stu

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2

… Planetary or Spur gear motor maybe?

3

Hello @stuwindsurf and welcome to the RobotShop community,

For high torque and fairly low RPM the best option would be a geared motor, and if you don’t need precision you don’t need a stepper.

You can find lots of options in the Gear Motors section of the store, you could use either brushed or brushless. Check if the specs listed match your requirements and also check if the values are before or after the geardown, if they are before then multiply the RPM and divide the torque by the gear ratio.

You can also check the DC Motors Comparison List to easily find a motor, I gave it a quick look and found this one:

I hope that helps!

1 Like
4

Thanks for your reply Geraldine, it’s much appreciated.

I will continue searching for a geared motor as you suggest, although at a quick glance I’m not sure I’ll find something with enough torque. I’ll keep looking though!

Thanks again
Stu

1 Like
5

Maybe one of these?

6

They both look great thanks, but unfortunately they don’t show up on the UK site for some reason. Maybe just not available in the UK

7

… would I be able to run one of these direct from a 24v 10a power supply via a reverse (pole changing) switch? or would I need a controller? I don’t need to adjust the speed

Many thanks
Stuart

8

You are correct, they are not available in the UK store.

And yes, if you don’t need to adjust the speed you can use a power supply, but you need one that can output a higher current because the stall current of the motor is close to 25A.

Here are some good tips for choosing a power supply:

  • Constant Current limit: Has the ability to provide full current should any anomalies arise if for example any overloads occur. This enables the motor to still start because this type of power supply has the capability to provide full current in these types of conditions.
  • Output diode required: To prevent the power supply being damaged by reverse voltage spikes which occur when the supply is turned off and the motor is slowing down.

More information about this here:

9

Thanks again for your reply. Could you recommend a suitable power supply? bearing in mind I have to keep this project cost effective!

I have managed to find a supplier for the motor.

Many thanks
Stu

10

I have managed to find a supplier for the motor.

For the same motor I linked?

If that’s the case then unfortunately the power supplies available on the site won’t work because they can’t supply enough current.

The easiest option would be using a battery. If you want to consider that option this guide should help: