REFLECTOR: IVO Repair?

[sbjknox]

----- 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

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