---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 03/08/19: 5 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:50 AM - Re: Landing gear electric actuator circuit (user9253) 2. 10:02 AM - Re: Re: Landing gear electric actuator circuit (Robert L. Nuckolls, III) 3. 11:19 AM - Re: Landing gear electric actuator circuit (user9253) 4. 04:54 PM - Re: Re: Landing gear electric actuator circuit (Robert L. Nuckolls, III) 5. 04:56 PM - Re: Re: Landing gear electric actuator circuit (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:50:40 AM PST US Subject: AeroElectric-List: Re: Landing gear electric actuator circuit From: "user9253" Below is a circuit to lower or raise a landing gear or to control the direction of any small PM DC motor. The toggle switch controls the motor direction of rotation. The relay turns the motor on and off. The limit switches open the relay circuit at end of travel, thus stopping the motor. Diodes across limit switches allow the current to reverse direction when a limit switch is open. On the right side, there is an optional emergency switch to lower the gear. Back to back zener diodes across the relay coil limit inductive voltage spikes. Disclaimer: The circuit has not yet been proven to work. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=487972#487972 Attachments: http://forums.matronics.com//files/long_ez_gear_423.jpg ________________________________ Message 2 _____________________________________ Time: 10:02:06 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Landing gear electric actuator circuit At 08:50 AM 3/8/2019, you wrote: > >Below is a circuit to lower or raise a landing gear or to control >the direction of any small PM DC motor. >The toggle switch controls the motor direction of rotation. >The relay turns the motor on and off. >The limit switches open the relay circuit at end of travel, thus >stopping the motor. >Diodes across limit switches allow the current to reverse direction >when a limit switch is open. >On the right side, there is an optional emergency switch to lower the gear. >Back to back zener diodes across the relay coil limit inductive >voltage spikes. >Disclaimer: The circuit has not yet been proven to work. This configuration does not place a hard short across the motor in the de-energized condition. This may not be important if stored kinetic energy on the motor does not produce an unsatisfactory over-shoot. Bob . . . ________________________________ Message 3 _____________________________________ Time: 11:19:59 AM PST US Subject: AeroElectric-List: Re: Landing gear electric actuator circuit From: "user9253" How about this? Is the purpose of shorting the motor to bring it to stop it quicker? -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=487975#487975 Attachments: http://forums.matronics.com//files/long_ez_gear_d_919.jpg ________________________________ Message 4 _____________________________________ Time: 04:54:07 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Landing gear electric actuator circuit > >Disclaimer: The circuit has not yet been proven to work. This configuration does not place a hard short across the motor in the de-energized condition. This may not be important if stored kinetic energy on the motor does not produce an unsatisfactory over-shoot. This is the advantage of using the spdt relays to control motor power and controlling relays through the panel and limit switches. http://www.aeroelectric.com/PPS/Flight/Flaps/Flaps_4.pdf Emacs! When the energized power relay relaxes, it throws a dead short on the PM motor. Back EMF generated in the motor produces a significant retarding force to the motor armature. The nice thing about this configuration is that dynamic braking occurs whether motion command is removed by the panel control switch -OR- a limit switch. I've been pondering the notion of adding a 'back up' circuit to supply down-stroke power to the motor. Every gear extension system I've encountered on TC aircraft had a back-up . . . but in EVERY case, the back-up mechanism was NON-electric. Some were quite simple and convenient (Beech Sierra - open valve in front of pilot's seat. Gear falls and locks). Some were not so convenient (Beech Bonanza - Slide pilot's seat all the way back, passenger seat all the way forward. Fly left handed while opening door under passenger seat. Extend handle and put some rotations on the crank until 'three greens' are showing. I think it took over 100 revolutions). The important feature is that normal and emergency extension systems do not share any required commodity . . . like electricity. The gear was MOST likely to fail do to loss of motor . . . except in the Bonanza which had a dynamic braking control contactor with a rather Rube-Goldbergish design. Bob . . . ________________________________ Message 5 _____________________________________ Time: 04:56:30 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Landing gear electric actuator circuit At 01:19 PM 3/8/2019, you wrote: > >How about this? >Is the purpose of shorting the motor to bring it to stop it quicker? > >-------- >Joe Gores > >Attachments: > >http://forums.matronics.com//files/long_ez_gear_d_919.jpg > Not bad! The only downside I see here is that the crew control switch carries motor current . . . which is not a horrible thing to contemplate. Bob . . . ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.