Testing a motor with a multimeter

[broncosdad1317]

can you test an already installed brushless motor with a multimeter and if so how?? Like what do you touch with the probes. Or do you have to take the motor out unsolder and if it works resolver it back in??

 

[VirtueViolater]

You can test motors in betaflight. What are you looking for in testing?

 

[VirtueViolater]

Also, when handling/mounting motors, be gentle, the leads are attached to the winding wires and its really easy to cause a short or cause it to dislodge

 

[broncosdad1317]

I'm trying to find out if a motor on my mjx bugs 3 is dead

 

[RENOV8R]

The standard method would be to trade the motor in question (call it #1) with another that's functioning properly (call it #2). If it still doesn't work, you know it's the motor. If it works, you know it's likely the ESC for #1

 

[theGreenOrange]

You need to desolder it to test it. Either replace with a spare as suggested, or spin the motor with a drill while reading voltage across pairs of motor leads. There are some good youtube videos on that. Other than that, you would need an LC meter.

 

[VirtueViolater]

Will the Bugs 3 fly in full acro?

 

[broncosdad1317]

Will the Bugs 3 fly in full acro?

Thanks guys and no the bugs 3 is stuck between a race drone and a toy haha no betaflight and no acro. Just mph of about 35-60 depending if I use my upgrade kit I sold them the other day. I had two. Got a buddy into the hobby with them and one of the motors is bad

 

[Keifie]

can you test an already installed brushless motor with a multimeter and if so how?? Like what do you touch with the probes. Or do you have to take the motor out unsolder and if it works resolver it back in??

You can desolder the motor and set your meter to Ohms. It doesn't matter which two wires you check, but place leads on & if you get reading w/leads on wires the motor should be fine. You are checking the elec windings

 

[theGreenOrange]

Rsistance wont tell you anything keifie, you need to measure inductance. Either that or spin the motor and measure voltage.

 

[Keifie]

Rsistance wont tell you anything keifie, you need to measure inductance. Either that or spin the motor and measure voltage.

Resistance told me one of my leads were broken loose inside one of my 1407 motors.

 

[theGreenOrange]

Resistance told me one of my leads were broken loose inside one of my 1407 motors.

Ok wasn't considering the physical break case, sorry. If your enamel is still in tact on the other phases I can see why you would not get continuity.

But usually a motor is bad because it burned out and just because it tests good for continuity doesnt mean it is good.

 

[Keifie]

Ok wasn't considering the physical break case, sorry. If your enamel is still in tact on the other phases I can see why you would not get continuity.

But usually a motor is bad because it burned out and just because it tests good for continuity doesnt mean it is good.

Agree. And that was my case. Ive also had higher voltage motors (non-quad related) that I’ve gotton resistance readings when windings are burned out (shorted). I am not an engineer nor a motor specialist. This has just worked for me.