Unexplained reversal of Electric Motor

[John Murdy]

I was flying my ST model Blaze the other day when through my own cockiness it had a coming together with terra firma. This knocked the nose off the aeroplane which has subsequently been glued back into position. I connected the motor back up, put a freshly charged battery in and checked all the controls, at this point I noticed that the motor was running in reverse. I double checked all the connectors and all was as should be but still the motor ran in reverse. I have subsequently reconnected the power leads from the ESC to motor swapping the red and yellow leads such by colour code they are now crossed. The motor now runs in the correct direction. The question is why has the motor reversed its rotation post the crash?

[Dave Hopkin]

I cant give you a reason but a club member crashed his ST Discovery on take off and smashed up the nose, when it was repaired. like you, the motor was reversed, we never figured out a reason for it so is it a common factor with the ESC ST use?

[GrahamWh]

Some ESCs do have reverse as a programmable function - could the esc have been damaged or a power irregularity somewhere in its circuitry in the crash have triggered this? Might be worth checking the ECS board and the soldering to its wires in case any thing is damaged.

[mightypeesh]

Have you connected the motor wires back correctly? If you swop any two over (regardless of what colour they are) it will run the other way. Just because the motor wire colours match from the esc and the motor it does not mean it will run the right way around. Give it a go I am sure it will sort it out. I put a new motor in my glider today and had to swap wires when I connected up to get it to run the right way.

Good luck, cheers, Simon

Edited By mightypeesh on 11/06/2015 21:30:48

Edited By mightypeesh on 11/06/2015 21:31:39

[John Murdy]

Thanks for all your quick reponses.

Dave, it's interesting that the ST Discovery exhibited this same symptom, as the Blaze has the factory supplied power train as standard.

Graham, the ESC is none programmable so can't do much there. I've checked the integrity of the wires as far as I can see and all seems ok.

Simon, prior to the crash the wires to the motor were connected as per the correct colour codes, post the crash the motor only runs correctly if I swap the red and yellow wires.

It could be that the ESC took an irregular power surge prior to disconnecting which has upset the ESC logic. Out of curiousity I will swap the ESC with a spare I have to isolate whether the fault is in the motor or ESC.

I'll keep you posted on this test.

Thanks for your inputs, John

[Dave Hopkin]

DItto on the discovery John, when the motor was disconnected in the Discovery the wires were connected colour for colour, when put back it was reversed..... and easy fix but curious!

I can only assume some power irregularity in the crash activated some hidden chip logic and reversed the motor direction

Mind you I have an ESC (not an ST one) that seems to refuse to retain the stick calibration about half the time!