Free Spinning 150:1 Metal DC Motor

Support Motor controllers/drivers and motors
1

Hi Everyone.

what i have

This is my first time working with DC motors.
I’ve got this This Motor and I’m using This Driver.

She spins a champ. :slight_smile:

problem

When I bought this motor I was expecting that, with the motor disconnected from power, it would be able to spin freely. I knew it would be tough due to the relatively high gear ratio, but even with pliers It’s a rock. I can’t get it to spin.

context

The context is that I was hoping to spin a pirate ship wheel (45cm diameter @1kg). The idea is that I can use the wheel, spinning freely, with the motor disconnected motor. However, I can then connect the motor to power and then drive it with my motor driver and some MCU.
(for clarity, this is not a real ship, and will not be used for nautical navigation.)

question

Is it just way tougher than I thought to turn, or is there some clever tech that is preventing me from turning it manually?

Thanks in advance.
Pix :heavy_heart_exclamation:

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2

Helical pinion or worm-gear gearboxes cannot be back-driven, by design.

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3

Hello.

I am not an expert on every type of helical gear out there, but the helical pinion gears used in our 37D gearmotors are backdrivable (though our gearmotors are not specifically intended or designed for that).

We have not characterized the torque required to backdrive our motors in detail, but we expect the high ratio gearmotors (like the 150:1) to generally be impractical to backdrive. For an application where you do need to move the load by hand when the motor is turned off, you might consider adding a clutch mechanism, though we do not have any specific recommendations for that. Alternatively, you might consider switching to a stepper motor since it is usually possible to command stepper motor drivers to de-energize the coils so that the only resistance from the motor will be the detent torque, which tends to be very low.

- Patrick

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4

Thanks @PatrickM
I’ll experiment with my options.
Thanks so much for that clarification.

What I learned was:

  • Technically possible.
  • Pragmatically, I may choose to research alternatives.

I’ll report back here when I’ve found a solution.

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