OSCILLATING PROP

[jetpipe]

After a normal flight with my electric plane powered by a Pichler brushless motor and esc , it refuses to run. The prop does not rotate but oscillates back and forth.

      What has happened?

[simon_t]

Assuming the supply battery is charged and in good condition, maybe one of a number of things:

- One of the 3 wires from speed controller to motor is open circuit/broken

- One phase of the speed controller has failed (FETs damaged)

- Open circuit or short circuit winding in motor

- Motor magnet has come lose/is catching inside motor

Things to do:

Does the motor turn smoothly and without any strange noises?

If you disconnect the speed controller, do you have a multimeter that you can use on ohms setting to check the resistance between each of the windings? - make sure there are no open/short circuits

Check wires to motor for broken wires or bad solder joints.  Do pull test on connectors.

Maybe check speed controller on another motor

Good luck in fault finding.

Simon

[heli_bee]

One of the three motor windings is not getting a signal from the speed controller. Check the connections between the speed controller and the motor. If all okay, try a different speed controller. If the fault persists then a motor winding may have failed.

[jetpipe]

Thanks very much chaps. The connections seemed ok so I put in a new esc and all is well. I wonder why it died. It just gave up. I did have the feeling that it had been a bit depressed lately.

[jetpipe]

The sequel:-     a bit later the new esc exhibited the same symptoms, but I couldn't find a bad connection so I tried the old esc and it works fine. I suppose it means there is a dodgy connection somewhere which will probably show up next time I go to the field. Oh well.

[PeteMitchell]

Sounds like you have a 'cold' solder joint in one or more of the motor wire gold plugs. Had that problem myself, and to sort the problem out  I had to re solder all three plugs.