Can drive motor affect steering servo?

[Espeefan]

Sorry to hear that didn't help solve your problems, Ken. The next thing I would try is to solder some capacitors to the motor. At least two. One from the negative terminal to the motor can, and one from the positive terminal to the motor can. You can use anything from .001 uF to .1uF. Make sure they are the ceramic type capacitors. I've run up to three capacitors as well. If you use a third, it goes between the positive and negative motor terminals, in addition to the others already mentioned. It's a little old school, but it might be worth a shot!

[sparkycuda]

Nathan & Neil, thanks for the suggestions. I'll try both the chokes and capacitors. The motor is an Integy V11 and is supposed to already have the capacitors but it's worth a try. Relocated the steering servo last night and it seemed to make a small change. The servo does not pull to the left when the motor runs above 1/3, it just won't return to center when you quit steering. Kill the motor, steering re-centers and away you go. Or, if I just creep along at slow speed, steering works properly. And I thought the electronics was going to be the easy part! I'll keep trying.
Thanks to everyone for the help!

Ken

[WhiteWolf McBride]

I agree with the 'choke' idea, aka, a ferrite core.

You often see then on monitor power cables and the like, its that bulge in the data cord. You can get clip-on two-part ones, or simple ring-shaped ones, but feeding a servo cable to wrap it around the ring a few times may be hard. You may also want to run the power feeds to the drive motor thru a core as well... 2 or three wraps of the power line minimum.

Bit I agree, its probably a electrical/magnetic feedback issue. With a separate battery supply, there is less direct path for the feedback in the wiring. Thats why it spikes when the RPM is cranked.

WhiteWolf

[sparkycuda]

Tried the easier "fix" first and added a Radio Shack snap-on ferrite core choke on the steering servo lead. The servo uses a large, twisted wire bundle and could only install one bundle through it - not wrapped as discussed. Guess what? The truck steers perfectly now! Even moved the servo back to its original position - still good! Then I tried using the ESC-BEC instead of separate battery - not good - the servo dithers on its own, but not in relation to motor speed. So tomorrow I install the external BEC and we'll see if is okay.

Thanks to everyone for suggestions. Now to finish the cab mount and see about a video.

Ken

[WhiteWolf McBride]

Sparky,

Glad to see ya got it solved. Give us some pics if ya get the chaance, we may need to use thre thread to help others, and a good set of reference pics would be a benefit, eh?


WhiteWolf,
off to try for the first full night's sleep in a week...