Fried motor problem

To anyone who can help,

I was inspired by David’s Tricopter builds, but finally decided to go with Jason Peterson’s
My list of parts is exactly as his, i.e. RCTimer’s 2830/8 1300KV Outrunner Brushless Motors and
Hobbyking SS Series 18-20A ESCs, etc., except for the battery.
The ZIPPY Flightmax 3000mAh 3S1P 20C was not in stock, so I bought this one instead: Turnigy 3300mAh 3S 20C Lipo Pack.

I also went for the: Hobbyking X900 Tricopter Glass Fiber Multi-Rotor Frame, instead of his wooden frame.

As I am a newbie to all this I took things very slowly. I flashed the controller with the V1.6 firmware.
The receiver was already bound to the T9X. I chose the Helicopter 90 degree setting.
I checked that all the motors were rotating in the correct direction and the that the yaw mechanism was working via the T9X.
I then tried to get all the motors to start at the same time by trimming the controls on the T9X and managed to get them right but not always.

Finally I balanced the props and mounted them on the motors.
I tried to repeat the process by just giving the T9X just enough throttle to start the motors,
so I was not revving them enough to lift the tricopter, when I noticed the left front prop alternatively turning in both directions then the motor started to smoke!
I switched off and disconnected the battery immediately.
I let the motor and ESC cool down and tried to power up again, but instead of the usual chirping and silence, I got several chirpings from the ESCs.
When I disconnect the motor and powered up again I got the normal chirping from the ESCs, so I guess the motor is fried, the windings do look a bit darker in parts.

What do you think? Was I just unlucky with a duff motor, or did I do something wrong?
Perhaps the LIPO is too powerful for this configuration? (It is only a 3300 20C as opposed to Jason’s 3000 20C)
Perhaps the frame is too heavy although I did not try to get it off the ground.
Or can you think of something else?

I have ordered a new motor from RCTimer and a new ESC from HobbyKing, but I will wait to hear from this site before trying to connect it all up again,
in-case you have some good advice?


4 thoughts on “Fried motor problem

  1. Hi,

    It seems like you had bad luck and got a bad motor.
    When you get the new one you can test it doing a “dry run”: run the engine with the ESC directly connected to throttle channel (ch. 3 on Futaba/Hitec) on the receiver.

    Also (depending on flightcontroller) you can calibrate throttle, so that all ESC’s start at the same time. Search and you will find… 🙂

    God luck!

    // Holmkvist

  2. Hej Chris,

    I also think it was bad luck. You don’t fry a motor because of the battery capacity but you can do so if you use a higher voltage than the motor accepts (e.g. a 3S battery in 1-2S motors) but smoke… hmmm… that looks more like a short circuit to me, a defectuous motor. Also check that the ESCs accept the voltage you wanna use and can provide 20-30% more current than the maximum of the motor. I assume the instructables guy already did that but it is always good to double-check, perhaps you can find an even better alternative.

    Further comments: for multicopters one should use an Acro model type in the transmitter (and with no mixings, etc.) so I found strange you use an Heli type (but tris are a bit special and haven’t build one, I have quads and hexas, so verify my statement somewhere else).

    About calibrating the ESCs: you don’t usually calibrate the ESCs via the transmitter but using a sequence of actions in the throttle stick while hearing the ESCs’ chimes so, check the manual of your ESCs.


  3. I actually ran into the same problem. If it was a bell style motor, the leads coming from the stator is 3 sets of 3 wires twisted together. That’s actually 9 wires. If one of the wires gets snapped the motor will cog, kind of like alternating forward and reverse. They will get hot. And melt you wires into a chunk of copper on iron. There’s a internal resistance and it should be the same from all three wires or connectors. I had managed to wreck into my living room wall ripping the motor off the mount pulling the wires loose. Also on all your motors new and used I would re solder your connectors. That could keep you from unexpectedly having to order a new one. Good luck!

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