Twitchy servo's

[david h]

Dear all,

I've just completed my new WTC and don't use a speed controller. (Bit expensive)

I've designed a "Switchplate" It comprises a servo with the two horns attached to the motor contacts. These horns alternate between two sets of contacts on a plate to either run the motor forward of reverse. You can probably visualise it. Simple . Problem is it's the only servo that twitches. The switchplate works well but the twitching is just annoying me...

Is there interference caused by a current going through the switchplate.

Any electronics guru's out there with ideas?

regards.

David H

[JWLaRue]

David,

Do you have any noise

David,

Do you have any noise suppression capacitors on the motor? If not, that's the first place I start.

Also, if you are running the servo wires alongside the motor wires, they should be separated.

-hope this helps as a start. Let us know if either of these apply and if not we'll keep offering help.

Jeff

[david h]

G'day jeff,

I've got suppression capacitors

G'day jeff,

I've got suppression capacitors on the motor. I have also got the motor cables running next to the servo lead. ( they run down a channel that runs through the middle of the Ballast tank. I cannot escape this. But why does this not effect the other servo?

dave H

[JWLaRue]

Hi David,

When a servo cable

Hi David,

When a servo cable is run alongside a power cable, the servo cable can get interference through electrical inductance. It's not a guranteee that you will get interference, but it is a common problem.

As a test, move the servo cable out of the common channel and see if the problem persists.

-Jeff

[skip asay]

David -

It's also possible that

[color=#000000]David -

It's also possible that you have a bad servo. Rule that out before you go too deep into other areas by switching that servo with one of the others that don't twitch. If that servo still twitches, replace it. If not, then continue your search.

Another tip]

[bradv]

Hi David,

I've had exactly what

Hi David,

I've had exactly what Skip's describing with my Kilo. Benchtesting, my rudder server was rock-solid. As soon as the sub got more than a couple of metres away from me in the pool, the rudder started twitching like mad! The ESC was also cutting out intermittently. I just put these down to interference in the pool until my rudder servo locked up and I had to replace it. After that, no more twitches and the ESC issues were gone too, at any range.

I already had filter caps across my motor, so it was clearly the bodgy servo feeding back into the system. Weird!


P.S. After a minor rebuild, my Kilo is now *very* smooth and a lot quieter too