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trigo(at)mail.telepac.pt Guest
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Posted: Sun May 21, 2017 1:48 am Post subject: Flaps system tripping the circuit breaker |
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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
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chaskuss(at)yahoo.com Guest
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Posted: Sun May 21, 2017 3:16 am Post subject: Flaps system tripping the circuit breaker |
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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.
Charlie
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On Sun, 5/21/17, Carlos Trigo <trigo(at)mail.telepac.pt> wrote:
Subject: Flaps system tripping the circuit breaker
To: aeroelectric-list(at)matronics.com
Date: Sunday, May 21, 2017, 5:47 AM
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. Â 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. Â 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. Â Now the question: which can
be the reason for the current peak that the motor is
reaching at full retraction?  Any help welcomeThanksCarlos Â
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ceengland7(at)gmail.com Guest
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Posted: Sun May 21, 2017 3:46 am Post subject: Flaps system tripping the circuit breaker |
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On Sun, May 21, 2017 at 4:47 AM, Carlos Trigo <trigo(at)mail.telepac.pt (trigo(at)mail.telepac.pt)> wrote:
Quote: |
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.
Â
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.
Â
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.
Â
Now the question: which can be the reason for the current peak that the motor is reaching at full retraction?
Â
Any help welcome
Thanks
CarlosÂ
Â
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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
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matronics(at)rtist.nl Guest
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Posted: Sun May 21, 2017 3:46 am Post subject: Flaps system tripping the circuit breaker |
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Is there a functional limit switch in this system? If you hit the physical end of travel for the flap system and there's no limit switch, the motor will keep on pulling at maximum power. Current draw will be a lot higher and if it wasn't for the CB, you'd probably burn up the motor.
On 5/21/2017 11:47 AM, Carlos Trigo wrote:
Quote: | <![endif]--> <![endif]-->
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
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Mauledriver(at)nc.rr.com Guest
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Posted: Sun May 21, 2017 7:40 pm Post subject: Flaps system tripping the circuit breaker |
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Just an aside but this issue helps justify the decision to make the only
CBs in my RV for the AP, the voltage regulator and flaps (none have
tripped to date however). Everything else is protected by fuses that I
don't intend to 'reset' in the air
Bill "keeping the pilot as proficient as the plane is the perpetual
challenge" Watson
---
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus
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wstucklen1(at)cox.net Guest
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Posted: Mon May 22, 2017 4:29 am Post subject: Flaps system tripping the circuit breaker |
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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
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