Welcome to PhantomPilots.com

Sign up for a weekly email of the latest drone news & information

P3P Motor Test

Discussion in 'Pro/Adv Discussion' started by AJC, Mar 27, 2016.

  1. AJC

    AJC

    Joined:
    Jan 1, 2016
    Messages:
    22
    Likes Received:
    3
    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
     
  2. Air Ontario

    Joined:
    Jan 11, 2016
    Messages:
    1,271
    Likes Received:
    493
    Location:
    U.S./ Canada
    can't you just check the resistance? In Ohms?
     
  3. AJC

    AJC

    Joined:
    Jan 1, 2016
    Messages:
    22
    Likes Received:
    3
    I suppose it can be done. Do you happen to know how many Ohms across the leads I should be getting? Thanks
     
  4. alokbhargava

    Joined:
    Sep 28, 2015
    Messages:
    5,078
    Likes Received:
    1,634
    Location:
    San Francisco, CA
    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 :)
     
  5. Air Ontario

    Joined:
    Jan 11, 2016
    Messages:
    1,271
    Likes Received:
    493
    Location:
    U.S./ Canada
    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?
     
    #5 Air Ontario, Mar 27, 2016
    Last edited: Mar 27, 2016
  6. AJC

    AJC

    Joined:
    Jan 1, 2016
    Messages:
    22
    Likes Received:
    3
    Do you per chance happen to know how much voltage it will take to run the motor? Also, just across the black and red?
     
  7. N017RW

    Joined:
    May 2, 2014
    Messages:
    6,236
    Likes Received:
    1,612
    Location:
    Palm Beach Co.- FL
    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.
     
  8. AJC

    AJC

    Joined:
    Jan 1, 2016
    Messages:
    22
    Likes Received:
    3
    Thanks for the tip.
     
  9. Air Ontario

    Joined:
    Jan 11, 2016
    Messages:
    1,271
    Likes Received:
    493
    Location:
    U.S./ Canada
    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
     
    #9 Air Ontario, Mar 27, 2016
    Last edited: Mar 27, 2016
  10. AJC

    AJC

    Joined:
    Jan 1, 2016
    Messages:
    22
    Likes Received:
    3
    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.
     
  11. alokbhargava

    Joined:
    Sep 28, 2015
    Messages:
    5,078
    Likes Received:
    1,634
    Location:
    San Francisco, CA
    Did you disconnect ESCs before conducting this test?
     
  12. alokbhargava

    Joined:
    Sep 28, 2015
    Messages:
    5,078
    Likes Received:
    1,634
    Location:
    San Francisco, CA
    Meggar test is not needed for low voltage motors, yes it checks the insulation of windings.
     
    Air Ontario likes this.
  13. Air Ontario

    Joined:
    Jan 11, 2016
    Messages:
    1,271
    Likes Received:
    493
    Location:
    U.S./ Canada
    Sounds pretty good although I was expecting higher micro henrys.
     
  14. AJC

    AJC

    Joined:
    Jan 1, 2016
    Messages:
    22
    Likes Received:
    3
    Yes. The motors were completely out of the circuit.
     
  15. Jason Bowlin

    Joined:
    Mar 19, 2016
    Messages:
    6
    Likes Received:
    0
    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.
     
  16. AJC

    AJC

    Joined:
    Jan 1, 2016
    Messages:
    22
    Likes Received:
    3
    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.