---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 02/09/22: 9 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:22 AM - ground power deep discharge of battery (werner schneider) 2. 02:34 AM - Re: ground power deep discharge of battery (Werner Schneider) 3. 03:38 AM - Re: ground power deep discharge of battery (Werner Schneider) 4. 07:44 AM - Re: ground power deep discharge of battery (Robert L. Nuckolls, III) 5. 07:52 AM - Re: ground power deep discharge of battery (user9253) 6. 08:10 AM - PWM ELEVATOR TRIM SERVO SPEED CONTROL (user9253) 7. 08:37 AM - Re: ground power deep discharge of battery (Werner Schneider) 8. 08:41 AM - Re: Re: ground power deep discharge of battery (Werner Schneider) 9. 12:03 PM - Re: PWM ELEVATOR TRIM SERVO SPEED CONTROL (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 02:22:06 AM PST US Subject: AeroElectric-List: ground power deep discharge of battery From: "werner schneider" Hello Folks, never though about it but now with 2 partners things do just happen :( You can energize the ground power plug only via an external battery connection, however, when you later disconnect external power, the solenoid does stay energized, if someone forgets to switch off the power plug, this seems to have happened and in 4 days the battery was empty :( Anybody who has tackled that problem in a way that the solenoid controlling the power plug does disconnect, when external power is disconnected? the ground power plug is in the top left corner of the diag. Cheers Werner Read this topic online here: http://forums.matronics.com/viewtopic.php?p=505945#505945 Attachments: http://forums.matronics.com//files/glastar_ykp_1_7_a3_817.pdf ________________________________ Message 2 _____________________________________ Time: 02:34:34 AM PST US Subject: Re: AeroElectric-List: ground power deep discharge of battery From: Werner Schneider If I remove that 24 AWG wire it should be ok shoulent it? Now just wonder why I did add that wire!! Werner On 09.02.2022 11:21, werner schneider wrote: > > Hello Folks, > > never though about it but now with 2 partners things do just happen :( > > You can energize the ground power plug only via an external battery connection, however, when you later disconnect external power, the solenoid does stay energized, if someone forgets to switch off the power plug, this seems to have happened and in 4 days the battery was empty :( Anybody who has tackled that problem in a way that the solenoid controlling the power plug does disconnect, when external power is disconnected? the ground power plug is in the top left corner of the diag. > > Cheers Werner > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=505945#505945 > > > Attachments: > > http://forums.matronics.com//files/glastar_ykp_1_7_a3_817.pdf > > ________________________________ Message 3 _____________________________________ Time: 03:38:38 AM PST US Subject: Re: AeroElectric-List: ground power deep discharge of battery From: Werner Schneider Sorry, not my day it seems, that is not a 24 AWG it's the 2AWG and I can not leave it out. On 09.02.2022 11:34, Werner Schneider wrote: > > > If I remove that 24 AWG wire it should be ok shoulent it? > > Now just wonder why I did add that wire!! > > Werner > > On 09.02.2022 11:21, werner schneider wrote: >> >> >> Hello Folks, >> >> never though about it but now with 2 partners things do just happen :( >> >> You can energize the ground power plug only via an external battery >> connection, however, when you later disconnect external power, the >> solenoid does stay energized, if someone forgets to switch off the >> power plug, this seems to have happened and in 4 days the battery was >> empty :( Anybody who has tackled that problem in a way that the >> solenoid controlling the power plug does disconnect, when external >> power is disconnected? the ground power plug is in the top left >> corner of the diag. >> >> Cheers Werner >> >> >> >> >> Read this topic online here: >> >> http://forums.matronics.com/viewtopic.php?p=505945#505945 >> >> >> >> >> Attachments: >> >> http://forums.matronics.com//files/glastar_ykp_1_7_a3_817.pdf >> >> >> >> >> >> > > ________________________________ Message 4 _____________________________________ Time: 07:44:49 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: ground power deep discharge of battery At 04:21 AM 2/9/2022, you wrote: > >Hello Folks, > >never though about it but now with 2 partners things do just happen :( > >You can energize the ground power plug only via an external battery >connection, however, when you later disconnect external power, the >solenoid does stay energized, if someone forgets to switch off the >power plug, this seems to have happened and in 4 days the battery >was empty :( Anybody who has tackled that problem in a way that the >solenoid controlling the power plug does disconnect, when external >power is disconnected? the ground power plug is in the top left >corner of the diag. This is not an uncommon problem with incorporation of the Cole-Hersey style ground power jack. The big-daddy of ground power jacks has a third pin that sequences closure of contactor with respect to mating and demating of power pins . . . it also manages power to the ground power contactor preventing the situation you've observed. https://tinyurl.com/y9579yvo I've had this discussion with readers over the years but not sure if we hashed it out here on the List. Waaayy back when, one of my readers installed the AEC9005 battery management module on his ground power contactor. Seems he ONLY used this jumper cables when ground power was supplied by an engine driven source (above 13.5 volts). Under what circumstances did the switch-left-on event occur? If you're using ground power to supplement/substitute for ship's battery to crank the engine, then presumably someone is at the controls. Perhaps a light on the panel to indicate CONTACTOR CLOSED would help. Another option is to install a timer that limits on-time for the contactor. A simple circuit could be crafted to shut the contactor down after, say 5 minutes after being energized. If you only use ground power to jumper to engine driven power source or a battery charger, then the voltage sensitive management of contactor function seems like the best bet. But this would be a pain in the you-know-what for battery cart starts. If only intended to support an engine cranking operation, then you could add a relay to prevent energizing the ground power contactor until the starter contactor is also commanded to close. Bob . . . Un impeachable logic: George Carlin asked, "If black boxes survive crashes, why don't they make the whole airplane out of that stuff?" ________________________________ Message 5 _____________________________________ Time: 07:52:06 AM PST US Subject: AeroElectric-List: Re: ground power deep discharge of battery From: "user9253" Attached is a circuit that will shut off ground power contactor when master switch is turned off. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=505953#505953 Attachments: http://forums.matronics.com//files/ground_power_relay__136.png ________________________________ Message 6 _____________________________________ Time: 08:10:23 AM PST US Subject: AeroElectric-List: PWM ELEVATOR TRIM SERVO SPEED CONTROL From: "user9253" Van's RV-12 elevator trim servo speed is controlled by a PWM circuit. The theory is that the trim motor sees full voltage and therefore its torque is not reduced. Is that true? Some RV-12 owners have trouble adjusting the trim servo motor speed. The motor either runs too fast or not at all. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=505954#505954 ________________________________ Message 7 _____________________________________ Time: 08:37:55 AM PST US Subject: Re: AeroElectric-List: ground power deep discharge of battery From: Werner Schneider Thanks a lot Bob, the weak battery has a cold problem, so it was charged to warm up with low Amps which helpes (until we have the new battery). As teh switch is a bit out of sight (rule is switch off before disconnect) he forgot about it. I think I need to add a flashing light somewhere to remind him. Thanks for confirmation Werner On 09.02.2022 16:43, Robert L. Nuckolls, III wrote: > At 04:21 AM 2/9/2022, you wrote: >> >> >> Hello Folks, >> >> never though about it but now with 2 partners things do just happen :( >> >> You can energize the ground power plug only via an external battery >> connection, however, when you later disconnect external power, the >> solenoid does stay energized, if someone forgets to switch off the >> power plug, this seems to have happened and in 4 days the battery was >> empty :( Anybody who has tackled that problem in a way that the >> solenoid controlling the power plug does disconnect, when external >> power is disconnected? the ground power plug is in the top left >> corner of the diag. > > =C2- This is not an uncommon problem with incorporation of the > =C2- Cole-Hersey style ground power jack. The big-daddy > =C2- of ground power jacks has a third pin that sequences > =C2- closure of contactor with respect to mating and demating > =C2- of power pins . . . it also manages power to the ground > =C2- power contactor preventing the situation you've > =C2- observed. > > https://tinyurl.com/y9579yvo > > =C2- I've had this discussion with readers over the > =C2- years but not sure if we hashed it out here on > =C2- the List. Waaayy back when, one of my readers > =C2- installed the AEC9005 battery management module > =C2- on his ground power contactor. Seems he ONLY > =C2- used this jumper cables when ground power was > =C2- supplied by an engine driven source (above 13.5 > =C2- volts). > > =C2- Under what circumstances did the switch-left-on > =C2- event occur? If you're using ground power to > =C2- supplement/substitute for ship's battery > =C2- to crank the engine, then presumably someone > =C2- is at the controls. Perhaps a light on the panel > =C2- to indicate CONTACTOR CLOSED would help. > > =C2- Another option is to install a timer that > =C2- limits on-time for the contactor. A simple > =C2- circuit could be crafted to shut the contactor > =C2- down after, say 5 minutes after being energized. > =C2- If you only use ground power to jumper to engine > =C2- driven power source or a battery charger, then > =C2- the voltage sensitive management of contactor > =C2- function seems like the best bet. But this > =C2- would be a pain in the you-know-what for > =C2- battery cart starts. > > =C2- If only intended to support an engine cranking > =C2- operation, then you could add a relay to > =C2- prevent energizing the ground power contactor > =C2- until the starter contactor is also commanded > =C2- to close. > > > =C2- Bob . . . > > =C2- Un impeachable logic: George Carlin asked, "If black boxes > =C2- survive crashes, why don't they make the whole airplane > =C2- out of that stuff?" > ________________________________ Message 8 _____________________________________ Time: 08:41:44 AM PST US Subject: Re: AeroElectric-List: Re: ground power deep discharge of battery From: Werner Schneider Thanks Joe, so you can only charge/start when you push the momentary switch, or the master is on. But interesting idea, will have to think about. Cheers Werner On 09.02.2022 16:51, user9253 wrote: > > Attached is a circuit that will shut off ground power contactor when master switch is turned off. > > -------- > Joe Gores > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=505953#505953 > > > Attachments: > > http://forums.matronics.com//files/ground_power_relay__136.png > > ________________________________ Message 9 _____________________________________ Time: 12:03:36 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: PWM ELEVATOR TRIM SERVO SPEED CONTROL At 10:10 AM 2/9/2022, you wrote: > >Van's RV-12 elevator trim servo speed is controlled by a PWM circuit. >The theory is that the trim motor sees full voltage and therefore >its torque is not reduced. >Is that true? >Some RV-12 owners have trouble adjusting the trim servo motor speed. >The motor either runs too fast or not at all. > >-------- >Joe Gores What are they using for speed control? Series control like a variable resistor isn't going to work. A PWM controller is better but it's not ideal. The recommended speed control management provides an ADJUSTABLE, CONSTANT VOLTAGE (REGULATED) SOURCE TO THE MOTOR. Here's one approach I crafted for a builder about 17 years ago: http://aeroelectric.com/PPS/Flight/Trim/trim6.pdf His pitch trim motor was rather hefty . . . it drew enough current to required one of the larger LM317 devices. If we're talking about the little MAC actuators, the smallest of LM317 (plastic TO220) will suffice. There's a hangar full of bad science out there about motor performance but here's a place to start: The attached curve is an EXEMPLAR performance plot for a PM motor. Note that TORQUE is directly proportional to CURRENT. RPM is proportional to VOLTAGE. Hence, assuming that the motor is operating within design limits, a slowing motor is starved for VOLTAGE. In the case of a trim system, torque loads are not a function of trim speed . . . so if speed regulation is poor, it's a prime notice that VOLTAGE regulation is poor . . .series resistors turn a constant voltage source into a wet noodle. Note that there is ONE plot for torque vs. current that's true for ALL voltages. No load RPM and STALL current are proportional to voltage (note 6v stall is 1/2 that of 12v stall). ACTIVE voltage regulators incorporated as suggested in the drawing are CONSTANT VOLTAGE sources irrespective of load. Motors do not automatically 'draw more current' as their driving voltage is reduced. Using a series resistor to control speed makes speed regulation so poor that it SEEMS as if motor current is being modulated with speed . . . not so. Bob . . . Un impeachable logic: George Carlin asked, "If black boxes survive crashes, why don't they make the whole airplane out of that stuff?" ------------------------------------------------------------------------------------- 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.