BB_DF

For anyone using or replacing the HD motors, here is something that needs to be constantly checked. On a previous thread I had addressed the issue of a motor failure caused by the brush wires being bent in such a way as to not allow the brushes to move freely in their channels. I just got a set of HD motors from DFI, so I can verify the problem comes with the new motors.

Picture #1 shows the four HD motors fresh out of their wrapping. Notice that the brush wires are all pressed down nice and neat. Probably someone in shipping thought that they look better that way, or would be better protected. By doing this they have created a time bomb, because the wires cannot freely follow the brushes down their channels, and therefore after a couple of hours will start to cause the brushes to arc on the armature and then fail to make contact altogether.

Make sure that the wires are positioned as in picture #2 so that they can follow the brush in the channel as the spring adjusts for wear.

- Bruce

Old Man Mike

Just a follow up here to re-emphesize what Bruce posted. I think the HD motors are excellent BUT you really have to move those braided wires to the position shown by Bruce and recheck them before every flight. I believe every major crash I've had except one (the 0.8 sec power drop issue) has been from having one of those braided wires in a restrictive position. The typical response is that one of the motors will become intermittent and will cause a rapid angle dive.

One more note is to check the solder side of the wires. I've had a couple of my older HD motors which needed to be resoldered. What happens is that over time some of the strands of wires will break which causes more heat in the remaining strands followed by additional breaks from the heat stress. Resoldering with a little extra solder to recapture the broken strands helps to keep maximum current to the motors and the heat down at the solderpoint.

Mike

VRNowhere

I can't wait until Spectrolutions comes out with a brushess DF, then heat and brush problems should be a thing of the past.

BB_DF

Mike - thanks for getting me back onboard!!! And thanks too to Sky for your help.

Next time you make an order from DFI, do it by phone and tell them you need a set of HD motor brushes. They sent me a set for free. It's easier to unsolder and replace the brushes and braided wires than replace a motor, or you can rework your old motors for spares. They're too expensive to chunk after just a few hours.

Cheers,
Bruce