P3P Motor Test

[AJC]

If I remove the motors from the circuit. what amount of voltage can be applied to the leads (Black and Red) in order to see if the motors are shorted? Or can this not be done?

Thanks!

Anthony

 

[Air Ontario]

can't you just check the resistance? In Ohms?

 

[AJC]

I suppose it can be done. Do you happen to know how many Ohms across the leads I should be getting? Thanks

 

[alokbhargava]

Resistance checking will not work as you need precision ohm meter for that. You can test by using a DC power supply with current limits. Set the current limit to say 0.5 A and start increasing the voltage to few volts gradually. Don't keep them running for long as there is no cooling without props. Ensure you hold the motors tightly

 

[Air Ontario]

Determine the windings I suppose and test 1-2 2-3 and 3-1 or whatever and see if they are basically zero or the same between them all or they all are balanced. If there is a big resistance you have an issue or if the readings aren't equal you have an issue. Resistance Ohms checks the copper windings.

Megging checks the insulation right?

 

[AJC]

Resistance checking will not work as you need precision ohm meter for that. You can test by using a DC power supply with current limits. Set the current limit to say 0.5 A and start increasing the voltage to few volts gradually. Don't keep them running for long as there is no cooling without props. Ensure you hold the motors tightly

Do you per chance happen to know how much voltage it will take to run the motor? Also, just across the black and red?

 

[N017RW]

If you haven't crashed or had an ESC failure you can just about guarantee the motors are fine.
You will not be able to apply a voltage to any of the leads and run the motors.
Google BLDC motors to learn how they work.

 

[AJC]

If you haven't crashed or had an ESC failure you can just about guarantee the motors are fine.
You will not be able to apply a voltage to any of the leads and run the motors.
Google BLDC motors to learn how they work.

Thanks for the tip.

 

[Air Ontario]

If you have 3 leads for example. Do a resistance test(ohms) between 1-2, then 2-3, then 3-1. They should all be equal in resistance OR all read zero. If they don't and read high resistance You have a short/bad motor winding.

Running current thru with a meggar checks the insulation to determine a short as seen with an ohm meter.

Or buy a 30 dollar LC meter off e bay and check it like you would with a multimeter

 

[AJC]

I look my LC meter and measured the inductance. I had 0.03mh across all three leads on each motor as well as 0.6ohms resistance so there is consistency.

 

[alokbhargava]

I look my LC meter and measured the inductance. I had 0.03mh across all three leads on each motor as well as 0.6ohms resistance so there is consistency.

Did you disconnect ESCs before conducting this test?

 

[alokbhargava]

Megging checks the insulation right?

Meggar test is not needed for low voltage motors, yes it checks the insulation of windings.

 

[Air Ontario]

I look my LC meter and measured the inductance. I had 0.03mh across all three leads on each motor as well as 0.6ohms resistance so there is consistency.

Sounds pretty good although I was expecting higher micro henrys.

 

[AJC]

Did you disconnect ESCs before conducting this test?

Yes. The motors were completely out of the circuit.

 

[Jason Bowlin]

If a brushless motor is shorted out you can feel it when spinning the shaft, if you can still feel the clicks/steps when you spin it its fine, if its shorted first of all it will be harder to spin and you will not feel the rotor clicks/steps at all, it will feel like your turning the shaft in a tub of grease.

 

[AJC]

Good to know. I am a bit apprehensive of putting the old motors on a new ESC board. I think when I get the new ones I will put the LC meter on them and see what they measure. If they are the same, I can assume the originals are ok. Thanks for the tip.