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nuckolls.bob(at)aeroelect Guest
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Posted: Sun May 21, 2017 9:43 am Post subject: Flaps system tripping the circuit breaker |
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At 06:14 AM 5/21/2017, you wrote:
Quote: | --> AeroElectric-List message posted by: Charles Kuss <chaskuss(at)yahoo.com>
Due to the mostly vertical orientation of the motor, the grease in the bearings will sometime migrate down onto the commutator/brush area of the armature. This is a common issue. It requires removal and disassembly of the motor to clean the grease off the armature and re-grease the bearings. |
Contamination of the commutator can indeed
manifest in mis-behavior of the motor but
not over-current. Are these ball bearings?
If so, they are most likely a metric standard.
You might fix the problem with factory lubricated,
sealed bearings.
Bob . . .
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nuckolls.bob(at)aeroelect Guest
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Posted: Sun May 21, 2017 9:51 am Post subject: Flaps system tripping the circuit breaker |
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Quote: |
My 1st guess is that the flap linkage is slightly out of adjustment. If the flaps hit their stops before the motor reaches full retraction, it would still trying to pull instead of free-wheeling.
My 2nd guess (after looking at the 10A flaps breaker in my RV-4, and looking at the specs for the motor that's inside the actuator) is that he's using the wrong breaker.
Corollary to my 2nd guess is that he's holding the up button too long. Â
Charlie |
Agreed. The spec sheet shows a motor resistance of
0.83 ohms. Add another few tenths of an ohm for wiring
and we still have an inrush current potential on the
order of 10 amps. So yes, the 5A breaker MIGHT be
marginal . . . but I would expect it to operate on
both extend or retract cycles . . . especially
extend when the motor is pushing flaps into
the slip-stream.
So your first guess sounds like the right one . . .
the flaps are hitting mechanical stops and
stalling the motor . . .
Well adjusted limit switches would be a
sanitary solution.
Bob . . .
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nuckolls.bob(at)aeroelect Guest
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Posted: Mon May 22, 2017 10:33 am Post subject: Flaps system tripping the circuit breaker |
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At 07:28 AM 5/22/2017, you wrote:
Quote: | First, the flap system in the RV’s has a clutch for travel to both ends of travel, so the flap motor never
actually goes into a stall condition. The motor current only goes up less than 2 amps over normal
ground bases travel currents. |
I was wondering about that . . . I seemed to
recall that the actuator was fitted with ball
screws and end-of-travel clutches. But
these are effective only if the ball nut reaches
end of stroke on the screw before the flap
mechanism bottoms out.
Quote: |
Second, aerodynamic pressures on the flaps raise the flap motor current significantly. To the point
That a 7 amp fuse or circuit breaker will definitely trip. And from my experiences in multiple RV’s I
Know that while flying, a trip can happen while extending or retracting the flaps.
I strongly suggest that you need to increase the amp rating of your circuit protection to at least
10 amps. If you do that, your problems will go away…. All the planes listed below have had 10 Amp
Circuit protections, and did not trip during flight….
Fred Stucklen
N924RV 1395 Hrs Flying
N926RV 875 Hrs Sold
N925RV 2008 Hrs Sold |
Thank you sir . . . good data!
Bob . . .
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