REFLECTOR: IVO Repair?

[John Dibble]

Thanks, Sid.  I also think a brush was stuck and I think the problem is that the
spring holds the braided wire, so as the brush wears it can't move toward the
commutator.  Time will tell.
Actually, I prefer flying to fixing and am easily tempted to pay someone.  Last year I
sent a motor to IVO 3 times before it got fixed.  That was my motivation to try and
fix it myself.
Gotta hold off on the beer.  My S-tec autopilot quit tracking gps and vor signals.
I've been told to send in the servo, but I plan to do some checking on this as well.

John

sbjknox wrote:

> ----- Original Message -----
> From: "John Dibble" <aminetech at bluefrog.com>
>
> Subject: REFLECTOR: IVO Repair?
>
> > I've put over 100 hours on the IVO hub that Travis generously gave me.
> > Lately it's been sluggish.  During a 5 hour trip 3 weeks ago I couldn't
> > get the rpm below 2600 and that was at a bit less than full power.
> > After sitting for 3 weeks, I made a short flight and it would not adjust
> > from fine pitch.  My ammeter showed no current going to the motor.  The
> > slip rings measured "open circuit", suggesting the motor was bad, so I
> > removed it.  Out of curiousity, I connected a battery charger to the
> > motor leads and was surprised when it ran fine.  So I re-installed it
> > and it worked fine for 5 seconds and then quit, again showing open
> > circuit.  I called IVO and they said the motor brushes might be worn, or
> > the springs weak and told me to send it in.  I decided to investigate a
> > little and removed the back cover and first sleeve, exposing the motor.
> > The brushes looked good and the springs seemed strong, but I have no
> > idea how strong they need to be.  The stationary end of one spring was
> > bent a little, so I straightened it.  Also the springs wrap around the
> > braded wire going to the brushes and I adjusted the wire a bit to be
> > sure it wouldn't interfere with the springs keeping the brushes in
> > place.  I put the cover back on and was ready to package it and send to
> > IVO, because it didn't seem like I did anything to fix it.  But I
> > decided to first re-install and see if there was any difference.  BIG
> > DIFFERENCE.  I went flying and the pitch adjusted quickly.  The rpm
> > easily dropped to 2400 at full power.  This is much better that it's run
> > in a long time.  Now if I can just figure out what I did....
> > The motor is made by Yokomo, a Japanese company.  I checked their
> > website and found a few motors for model cars.  I have no idea if this
> > is the same motor.  My motor had no other identification other than some
> > Japanese.  Anyone know about these motors?
> >
> > John
> >
> John, sounds to me like one of the brushes was "stuck" ie., not able to
> easily slide in its holder and thus not making good contact with the
> commutator.
> You are to be commended for digging into it and and trying (and succeding)
> to determine what was the cause of the problem rather than just roll over
> and pay someone else to fix your problem.
> It is of course possible that there is an underlying problem that will
> re-surface and will lead to the necessity to replace the motor but for now,
> buy yourself a beer and give yourself a "well done".
>
> Sid Knox
> Oklahoma
>
> Velocity  173 RG  N199RS
> Starduster  N666SK
> KR2         N24TC
> W7QJQ
>
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