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1. 05:29 AM - Re: Flaps system tripping the circuit breaker (Fred Stucklen)
2. 11:33 AM - Re: Flaps system tripping the circuit breaker (Robert L. Nuckolls, III)
Message 1
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Subject: | Re: Flaps system tripping the circuit breaker |
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.
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
One of my aviator friends called me to help him solving a problem in
his
RV-7 flaps system.
He told me that occasionally, when he retracts the flaps, the
correspondent
Circuit Breaker trips. But not always, so he resets the CB and the
flaps
keep working normally.
I asked him to measure the current during the flaps movement, and he
measured 1 to 2 A when extending and when retracting, but he noticed
that
after full retraction the current went to 7 A.
That explains why the CB (5A) trips.
I think most of you know that the flaps system in an RV airplane is
powered
by an electric motor with 2 wires, which make the flaps work in both
senses,
just with reversing the electrons movement on those 2 wires. You also
probably know that the motor doesn't stop at both ends if you don't
release
the switch, so the motor keeps turning even when the flaps reach full
extension and full retraction.
Now the question: which can be the reason for the current peak that
the
motor is reaching at full retraction?
Any help welcome
Thanks
Carlos
Message 2
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Subject: | Re: Flaps system tripping the circuit breaker |
At 07:28 AM 5/22/2017, you wrote:
>First, the flap system in the RV=92s 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.
>
>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=92s 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=85. All the planes listed below have had 10 Amp
>Circuit protections, and did not trip during flight=85.
>
>Fred Stucklen
>N924RV 1395 Hrs Flying
>N926RV 875 Hrs Sold
>N925RV 2008 Hrs Sold
Thank you sir . . . good data!
Bob . . .
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