Further Test results

[Peter Seddon]

Thanks to everyone who has contributed to what looks like being an intractible problem.

I have conducted further tests and the attached drawing may explain, the best case and worst case. I am still testing with everything laid on a board 'cos its easier to vary things that way. The problem is worst at half throttle.

It does indeed seem as QF8 suspects that the problem is coming up the signal wire of the receiver to ESC lead.

Ferrites were tried in a couple of places and did give some improvement as noted.

This has all been done with the PCM receiver aerial horizontal and without a vertical element.

The receiver lead to the ESC comes out over the power capacitors in the ESC and has a fairly high impedance so presumably is ripe for crosscoupling.

JETI have now asked me to send the controller back to them. However in early tests a ModelMotors controller gave similar problems (which makes me think I ought to try the MM controller again).

I searched on Gooseman and AXI and there was quite an interesting thread a couple of years ago which didn't seem to resolve itself but seemed to indicate a problem with certain specimens of AXI. Maybe I should try another motor. It also seemed it might be a problem associated with 35MHz - what frequency do you fly on QF8?

Wish it would stop raining then I could go and do some more tests although I am running out of ideas - a second opto between receiver and ESC, or a true optical link seems to be about all that is left.

Regards Peter

[vintage1]

If a bit of ferrite worked a bit, try more ferrite closer to the motor. Or more turns round the ferrite ring.

I take it you didn't combine that with caps across the motor leads. This will NOT affect sensing by the way - far too small in value for that - the aim is to lower the self resonance of the motor windings in the MHz range, not kill the audio frequency stuff that the motor actually uses.

[vintage1]

Just ahd a thought. Check to see if teh windings in teh motor are shorted to the case at any point.

If they are, return the motor.

If not,try earthing the motor case to receiver ground.

[Peter Seddon]

Following Vinatge's suggestion I checked the motor and there is indeed a winding to rotor short circuit. I have ordered a new motor - we'll see if that solves the problem.

Regards Peter

[vintage1]

Aha. I will follow with interest...

[QF8]

Im using 35mhz as well

Ive just got hold of another brand new Hacker 135 and a CC 8O so tonight i will do some range testing.

Ive found that i get pcm lockout at less than 20mtr. yet if i unplug the esc i get double the range.

I plan on testing the other two esc in conjuction with mine togeather under a controlled situation.

The lms has been very helpful in lending me this stuff.

you might want to do a range test peter with no main battery and no motor connected. just the esc plugged in then not plugged in. Why just an opto circuit reduces range has got me beat. Ill be interested to see if i get the same result with a diffrent esc after my testing.

[QF8]

Please also note that my Hacker is made by JETI. same animal with different spots