Maximum current for a 2208 gimbal motor

Hi all,
I’m currently designing a robot and am considering using a SimpleFOC mini board and gimbal motor for the actuators. There is a 2208 90KV gimbal motor listed on the motors page (see the link below). I would like to know what the current limit for such a motor is and I am struggling to find a data sheet. I expect the limit will be in the range of 1-2 amps, but would like to know more precisely. The current it can handle will affect the torque output and how much gearing is necessary for the actuator.

Is it possible to determine this from the KV / resistance / number of turns info when such is provided?

Any advice is appreciated.

Thanks
stu

Hello @stuguns

Welcome to the forum!

Yes, it is possible to determine the current from the resistance. It’s called Ohm’s Law:

It goes like Current = Voltage / Resistance

From your motor resistance, the current you can handle at 12V is 0.75A or 750mA.

If you apply 24V you can get 1.5A.

This is a small motor so I do not advise you to apply 24V, you may burn it.

The real current will probably be lower due to a lot more complex calculations involving the phase magnetic fields, however, this should be good enough for you to begin with.

Best of luck with your project and please post your progress, we want to learn from you.

Cheers,
Valentine

Hey @stuguns ,

I use these motors, and I use even less powerful drivers than the SimpleFOC mini.

In FOC control, with things calibrated right, they use just a few 100mA. If you stall the motor, currents can rise to 1A or so.
That’s on 6-10V.

In practical terms, running 1A through such a motor for any length of time will heat it up burning hot, and eventually destroy it by melting through the winding insulation or demagnetising the permanent magnets.

Running it with small loads at a few 100mA is possible indefinitely.

Thank you so much @runger and @Valentine for your responses.

So in terms of the thermal limit for the 2208, you are suggesting this is in the range of ~300 - 750 mA.

I would like to use the SimpleFOCmini board for the actuators for my robot due to its small form factor.
I see the current it can handle is 2A continuous or 3A peak.
Can you recommend a gimbal motor with similar current limits? I would like the board to be well matched to the gimbal motor, ideally getting as much torque out of the pair as possible (safety).

(I am focused on gimbal motors as I understand something like a hobby RC brushless motor has resistance which is too low and will draw too much current for the FOCmini board.)

Are there any gimbal motors that you are familiar with that would be broadly suitable?

Thanks
stu

Hey @stuguns ,

It’s very hard to make such a recommendation…
Really, any of the gimbal motors in sizes ≤ 41mm will probably work quite well with a SimpleFOC mini.
Motors are typically chosen based on torque and size/shape requirements of the application. Gimbal motors are higher ohm, so simplify the driver design, and can hold positions without burning up.
Generally speaking, you also get what you pay for, and more expensive brand name motors with nice bearings and higher quality workmanship will run more smoothly than the low-cost AliExpress “specials”.

So if you let us know more about your robot (are these wheel motors, or leg motors?), its intended size/weight and your goals regarding its actuation capabilities, then we’ll have a better picture of your needs.