---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sun 09/15/13: 10 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:46 AM - Re: Re: Looking for a circuit that when you press a button powers th (Robert L. Nuckolls, III) 2. 07:53 AM - Re: Re: Looking for a circuit that when you press a button powers th (Jeffrey Skiba) 3. 07:57 AM - Re: Re: Looking for a circuit that when you press a button powers th (Mike Welch) 4. 08:10 AM - Re: Re: Looking for a circuit that when you press a button powers th (The Kuffels) 5. 08:27 AM - Re: Re: Looking for a circuit that when you press a button powers th (The Kuffels) 6. 12:07 PM - Re: Re: Looking for a circuit that when you press a button powers th (Robert L. Nuckolls, III) 7. 02:07 PM - Re: Why does a master switch turn off devices? (Robert L. Nuckolls, III) 8. 03:28 PM - Re: Bad Crimp? (Vern Little) 9. 03:52 PM - Re: Why does a master switch turn off devices? (Robert L. Nuckolls, III) 10. 04:41 PM - Re: Why does a master switch turn off devices? (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:46:00 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Re: Looking for a circuit that when you press a button powers th At 03:01 PM 9/14/2013, you wrote: > >Driving a servo max current would be 900 milliamps. > > >.a circuit that will only be on for 3 seconds maximum, even if >you're still holding down the button. If you let go early, it turns >off early. Do I have that right? You GOT it Okay, this conversation is an excellent example of the $time$ that can be expended when the participants in a discussion all have different mental images of what's being asked . . . If I understand your design goals correctly you're wanting a trim motor run time limiter that will trip for any motor command exceeding 3 seconds . . . but resets as soon as power is removed. Hence, a series of trim commands of 3 seconds or less will be conducted to the motor without modification. A stick trim switch would, therefore be limited in how far the airplane could be driven out of trim by the fault. Do I presume correctly from the current draw value that we're talking about a Ray-Allen actuator? If so, then the motor to be controlled is a permanent magnet device wherein direction is determined by the polarity of applied voltage. This fact does not preclude putting the run-limit circuitry in the ground side of the supply power. This narration also suggests that the timing function need not be terribly accurate. A specification of 3.0 +/- 0.5 seconds would probably suffice . . . timer accuracy requirements drive selection of components. Is the narrative above accurate? The creative designers need to know before serious sifting of the ingredients suited to a recipe for success. Bob . . . ________________________________ Message 2 _____________________________________ Time: 07:53:46 AM PST US From: Jeffrey Skiba Subject: RE: AeroElectric-List: Re: Looking for a circuit that when you press a button powers th As usual Bob you are correct on all statements :-) The one other item I would like to add is to also include a two speed function. A slower rate of movement for the servo at a higher airspeed controlled by manual switch or airspeed switch, vs the full rate of the servo at slow airspeeds (pattern) again that portion could be store bought (ray allen speed control one example but those are $45 each so building one at the same time as the original requested circuit, I would think would be lots cheaper and I would learn something about it in the process) *Note I just found your drawing for two speed trim system but cannot find the Component "AEC9013-110-1 Speed Control" on your site any longer. Ref: http://www.aeroelectric.com/PPS/Flight/Trim/Two_Speed_Trim_2.pdf Does this drawing show everything to build the speed controller ? Sorry for wasting $time$ that can be expended when the participants in a discussion all have different mental images of what's being asked . . . Thanks in advance for everyone's time Jeff. --> At 03:01 PM 9/14/2013, you wrote: >--> > >Driving a servo max current would be 900 milliamps. > > >.a circuit that will only be on for 3 seconds maximum, even if you're >still holding down the button. If you let go early, it turns off early. >Do I have that right? You GOT it Okay, this conversation is an excellent example of the $time$ that can be expended when the participants in a discussion all have different mental images of what's being asked . . . If I understand your design goals correctly you're wanting a trim motor run time limiter that will trip for any motor command exceeding 3 seconds . . . but resets as soon as power is removed. Hence, a series of trim commands of 3 seconds or less will be conducted to the motor without modification. A stick trim switch would, therefore be limited in how far the airplane could be driven out of trim by the fault. Do I presume correctly from the current draw value that we're talking about a Ray-Allen actuator? If so, then the motor to be controlled is a permanent magnet device wherein direction is determined by the polarity of applied voltage. This fact does not preclude putting the run-limit circuitry in the ground side of the supply power. This narration also suggests that the timing function need not be terribly accurate. A specification of 3.0 +/- 0.5 seconds would probably suffice . . . timer accuracy requirements drive selection of components. Is the narrative above accurate? The creative designers need to know before serious sifting of the ingredients suited to a recipe for success. Bob . . . ________________________________ Message 3 _____________________________________ Time: 07:57:12 AM PST US Subject: Re: AeroElectric-List: Re: Looking for a circuit that when you press a button powers th From: Mike Welch Bob N, Didn't you already do this circuit for me two years ago, for that IvoProp electric Prop controller? Mike Welch ________________________________ Message 4 _____________________________________ Time: 08:10:14 AM PST US From: "The Kuffels" Subject: Re: AeroElectric-List: Re: Looking for a circuit that when you press a button powers th Jeff, Exactly the circuit you describe for two axis trim and two pilot control was published by me in the June 2013 Kitplanes magazine. If you leave out the fancy external (safety feature) controls and the variable speed capability the parts cost (including 8 amp relays) is less than $15. This compares well with the commercial unit Stein mentioned. If you don't have access to the Kitplanes Magazine E-Library I can email you pdf files of the schematic and the perfboard layout as well as the Bill of Materials. Tom ________________________________ Message 5 _____________________________________ Time: 08:27:36 AM PST US From: "The Kuffels" Subject: Re: AeroElectric-List: Re: Looking for a circuit that when you press a button powers th Jeff, << The one other item I would like to add is to also include a two speed function. >> The circuit I published (June 2013 Kitplanes magazine) does that also. All out full featured parts cost is $30 about 1/10th the TCW unit.. Tom Kuffel ________________________________ Message 6 _____________________________________ Time: 12:07:14 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Looking for a circuit that when you press a button powers th At 09:56 AM 9/15/2013, you wrote: > >Bob N, > > Didn't you already do this circuit for me two years ago, for that > IvoProp electric Prop controller? > >Mike Welch > > No, that was an electronic circuit breaker designed to be more accurate (and adjustable). That's on my list of things to become a product. Bob . . . ________________________________ Message 7 _____________________________________ Time: 02:07:07 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Why does a master switch turn off devices? At 02:17 AM 9/14/2013, you wrote: I've never quite understood something about aircraft electrical systems and I'm hoping someone here can enlighten me. I've always flown under the impression that a primary purpose of the master switch is to effectively connect/disconnect power from the electrical bus, which in turns provides for the flight instruments and other electrical devices in the cockpit. However, my question is that since the alternator is typically connected on the bus side of the master contactor (not the battery side), why doesn't the alternator continue to provide electrical power to the bus while the engine is running when the master is off? Or does it? I have to admit to not ever having tried to switch off the master in flight, but I've been under the impression that doing so should turn off the electrical equipment - it's after all, a recommendation to turn off the master in a forced approach. To achieve a solid understanding of how and why various are placed on the ship's control panel, it's useful if not a mitigation of risk, to understand what the controls do and why they're included. The legacy short answer to your question comes out of FAR23 as follows: Sec. 23.1361 Master switch arrangement. (a) There must be a master switch arrangement to allow ready disconnection of each electric power source from power distribution systems, except as provided in paragraph (b) of this section. The point of disconnection must be adjacent to the sources controlled by the switch arrangement. If separate switches are incorporated into the master switch arrangement, a means must be provided for the switch arrangement to be operated by one hand with a single movement. Okay. In times gone by, separate switches for battery(ies) and generator(s) were located right next to each other such that a downward stroke of two fingers or a 'crash bar' makes the electrical system go to max-dark. The infamous 'split-rocker' switch was birthed during the transition from generators to alternators on the single engine aircraft in the 1960s time-frame. It was discovered that alternators often would not come on line without having a battery on also to excite the field. It was also common wisdom that unlike generators (that self-excited and happily ran sans battery), it was good practice to make sure that a battery was ON any time an alternator was ON. Hence the infamous 'split rocker' switch seemed like a good idea . . . it could be fitted with mechanical interlocking of the two rockers such that you can operate battery only but any attempt to turn the alternator ON would add the battery also . . . further, any attempt to take the battery OFF would also shut down the alternator. This bit of mechanical slight-of-hand is easily accomplished with a progressive-transfer, ON-ON-ON toggle switch wired as shown http://tinyurl.com/kdqwahq and in many of the wiring diagrams in Appendix Z of the 'Connection. Do you have a copy of the book? (b) Load circuits may be connected so that they remain energized when the master switch is open, if the circuits are isolated, or physically shielded, to prevent their igniting flammable fluids or vapors that might be liberated by the leakage or rupture of any flammable fluid system; and (1) The circuits are required for continued operation of the engine; or (2) The circuits are protected by circuit protective devices with a rating of five amperes or less adjacent to the electric power source. (3) In addition, two or more circuits installed in accordance with the requirements of paragraph (b)(2) of this section must not be used to supply a load of more than five amperes. (c) The master switch or its controls must be so installed that the switch is easily discernible and accessible to a crewmember. From the electrical diagrams I've seen, it would seem as though that switching off the master while the engine is running should do nothing other than disconnect the battery from the bus, which would not prevent the alternator from continuing to power electrical devices . . . It depends on who's diagrams you've seen and what the designer calls a "master switch". Bottom line is that for every significant power source there should be a pilot controlled switch properly labeled as to which source is being controlled. . . . but instead merely remove the battery's ability to absorb transients, etc. Batteries are poor mitigators of bus noises and are effective only in mitigation of LARGE transients like energizing a hydraulic pump motor . . . Wouldn't the alternator continue to supply its own field current once it is already running, so long as the alternator switch remains on? Yes, unless your MASTER is wired like many a single engine airplane and the alternator is forced off with the battery. The modern Bonanzas have separate battery and alternator switches. It seems that the Bonanza alternators WILL self excite so ganging the alternator and battery switches together is not necessary. I think I'm missing something pretty basic here. Any help would be greatly appreciated! Do you have a copy of the AeroElectric Connection? Electrical system architecture and design goals are discussed at length. Also, check out hte articles on http://aeroelectric.com for further enlightenment. Bob . . . ________________________________ Message 8 _____________________________________ Time: 03:28:42 PM PST US From: "Vern Little" Subject: Re: AeroElectric-List: Bad Crimp? A few years ago, I had a strobe switch failure, and the terminals charred. The root cause is thermal runaway: A strobe power supply is a constant-power device. This means that if there is resistance in the switch circuit, it will draw more current to make up the different. This increased current makes the switch get hotter, increasing resistance, and so on. Eventually everything gets toasty and fails. The root cause of this was found (and reviewed by Bob) to be loose rivets on the Carling switches used in this application. After I switched to Honeywell switches (and changed the charred fast-ons), I=99ve had no problems. This loose rivet failure also occurred in my landing light circuit and master switch. Vern From: Dave Saylor Sent: Friday, September 13, 2013 2:36 PM Subject: AeroElectric-List: Bad Crimp? Bob, Can you tell from the photo if this is this a poor crimp? It was overheating on the back of a strobe switch. I recall Bill Watson had a crimp fail on a strobe switch recently as well. The strobes were occasionally intermittent but the wire near the terminal was always very hot to the touch. The insulation was discolored too. I changed the terminal and the last few inches of wire, and now all is well. Nice and cool. Any comments on the crimp would be much appreciated. Dave Saylor 831-750-0284 CL ------------------------------------------------------------------------- ------- No virus found in this message. Checked by AVG - www.avg.com 09/13/13 ________________________________ Message 9 _____________________________________ Time: 03:52:25 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Why does a master switch turn off devices? At 02:17 AM 9/14/2013, you wrote: I've never quite understood something about aircraft electrical systems and I'm hoping someone here can enlighten me. I've always flown under the impression that a primary purpose of the master switch is to effectively connect/disconnect power from the electrical bus, which in turns provides for the flight instruments and other electrical devices in the cockpit. However, my question is that since the alternator is typically connected on the bus side of the master contactor (not the battery side), why doesn't the alternator continue to provide electrical power to the bus while the engine is running when the master is off? Or does it? I have to admit to not ever having tried to switch off the master in flight, but I've been under the impression that doing so should turn off the electrical equipment - it's after all, a recommendation to turn off the master in a forced approach. To achieve a solid understanding of how and why various are placed on the ship's control panel, it's useful if not a mitigation of risk, to understand what the controls do and why they're included. The legacy short answer to your question comes out of FAR23 as follows: Sec. 23.1361 Master switch arrangement. (a) There must be a master switch arrangement to allow ready disconnection of each electric power source from power distribution systems, except as provided in paragraph (b) of this section. The point of disconnection must be adjacent to the sources controlled by the switch arrangement. If separate switches are incorporated into the master switch arrangement, a means must be provided for the switch arrangement to be operated by one hand with a single movement. Okay. In times gone by, separate switches for battery(ies) and generator(s) were located right next to each other such that a downward stroke of two fingers or a 'crash bar' makes the electrical system go to max-dark. The infamous 'split-rocker' switch was birthed during the transition from generators to alternators on the single engine aircraft in the 1960s time-frame. It was discovered that alternators often would not come on line without having a battery on also to excite the field. It was also common wisdom that unlike generators (that self-excited and happily ran sans battery), it was good practice to make sure that a battery was ON any time an alternator was ON. Hence the infamous 'split rocker' switch seemed like a good idea . . . it could be fitted with mechanical interlocking of the two rockers such that you can operate battery only but any attempt to turn the alternator ON would add the battery also . . . further, any attempt to take the battery OFF would also shut down the alternator. This bit of mechanical slight-of-hand is easily accomplished with a progressive-transfer, ON-ON-ON toggle switch wired as shown http://tinyurl.com/kdqwahq and in many of the wiring diagrams in Appendix Z of the 'Connection. Do you have a copy of the book? (b) Load circuits may be connected so that they remain energized when the master switch is open, if the circuits are isolated, or physically shielded, to prevent their igniting flammable fluids or vapors that might be liberated by the leakage or rupture of any flammable fluid system; and (1) The circuits are required for continued operation of the engine; or (2) The circuits are protected by circuit protective devices with a rating of five amperes or less adjacent to the electric power source. (3) In addition, two or more circuits installed in accordance with the requirements of paragraph (b)(2) of this section must not be used to supply a load of more than five amperes. (c) The master switch or its controls must be so installed that the switch is easily discernible and accessible to a crewmember. From the electrical diagrams I've seen, it would seem as though that switching off the master while the engine is running should do nothing other than disconnect the battery from the bus, which would not prevent the alternator from continuing to power electrical devices . . . It depends on who's diagrams you've seen and what the designer calls a "master switch". Bottom line is that for every significant power source there should be a pilot controlled switch properly labeled as to which source is being controlled. . . . but instead merely remove the battery's ability to absorb transients, etc. Batteries are poor mitigators of bus noises and are effective only in mitigation of LARGE transients like energizing a hydraulic pump motor . . . Wouldn't the alternator continue to supply its own field current once it is already running, so long as the alternator switch remains on? Yes, unless your MASTER is wired like many a single engine airplane and the alternator is forced off with the battery. The modern Bonanzas have separate battery and alternator switches. It seems that the Bonanza alternators WILL self excite so ganging the alternator and battery switches together is not necessary. I think I'm missing something pretty basic here. Any help would be greatly appreciated! Do you have a copy of the AeroElectric Connection? Electrical system architecture and design goals are discussed at length. Also, check out hte articles on http://aeroelectric.com for further enlightenment. Bob . . . ________________________________ Message 10 ____________________________________ Time: 04:41:24 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Why does a master switch turn off devices? Oops, sorry for the double posting of Part I. Here's the rest of the story about energy management switches in an airplane whether or not they are called "master switches". Consider this part of FAR23.1361 (b) Load circuits may be connected so that they remain energized when the master switch is open, if the circuits are isolated, or physically shielded, to prevent their igniting flammable fluids or vapors that might be liberated by the leakage or rupture of any flammable fluid system; and (1) The circuits are required for continued operation of the engine; or (2) The circuits are protected by circuit protective devices with a rating of five amperes or less adjacent to the electric power source. (3) In addition, two or more circuits installed in accordance with the requirements of paragraph (b)(2) of this section must not be used to supply a load of more than five amperes. This section goes to issues that took root in OBAM aviation, the electrically dependent engine. Some years back we began to consider and expanded role for the BATTERY BUS in powering electronic ignition systems and/or fuel pumps necessary for engine operation. The combination of switches one might call 'masters' is set apart from engine critical circuits. For crash safety, the FAA has embraced a "5A max" always hot feeders for a variety of tasks not the least of which was engine support. Paragraph (b)(3) seems to suggest that the sum total of power feeders taken directly from the battery bus should not exceed 5A . . . not sure of how this might be interpreted by the regulatory guru's I've known. Since FAR23 does not apply to our endeavors (at least not today) then the significance of (b)(3) is moot. Nevertheless, battery bus feeders greater than 5A might best be fitted with a disconnect relay at the bus . . . not unlike Figure Z-32 http://tinyurl.com/756ydec where it is shown as an auxiliary feed path to the e-bus. That same relay might power a fuel injection pump and be fused at much greater than 5A. The point of this semantic hat dance is to illustrate the wide range of power control switches that might find their way onto the panel of an airplane and to emphasize the fact that they might be called something other than a 'master switch'. Irrespective of what the switch is called, legacy design goals for making the electrical system go max-dark with a minimum of effort/confusion at the pilot's discretion is worthy of the builder's consideration 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.