---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 07/14/16: 18 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:14 AM - Re: Optima Prius Battery For TIO-540 (Charlie England) 2. 06:34 AM - Re: Lay Flat Battery Contactor and Starter Relay (Charlie England) 3. 06:46 AM - Re: Optima Prius Battery For TIO-540 (William Hunter) 4. 07:29 AM - Re: Lay Flat Battery Contactor and Starter Relay (William Hunter) 5. 11:12 AM - Contactor orientation (Robert L. Nuckolls, III) 6. 11:26 AM - Re: Question OV Crowbar connection in Z16 figure (zwakie) 7. 11:43 AM - Re: Contactor orientation (ARGOLDMAN@aol.com) 8. 12:03 PM - Speaking of 'drain holes' . . . (Robert L. Nuckolls, III) 9. 12:22 PM - Re: Optima Prius Battery For TIO-540 (Robert L. Nuckolls, III) 10. 02:39 PM - Can Someone PLEASE Double Check My Homework?!?!?! (William Hunter) 11. 03:03 PM - Re: Optima Prius Battery For TIO-540 (William Hunter) 12. 03:29 PM - Re: Can Someone PLEASE Double Check My Homework?!?!?! (user9253) 13. 04:10 PM - Re: Contactor orientation (Robert L. Nuckolls, III) 14. 06:42 PM - Re: Re: Can Someone PLEASE Double Check My Homework?!?!?! (William Hunter) 15. 06:59 PM - Re: Contactor orientation (Jim Baker) 16. 07:09 PM - Re: Re: Can Someone PLEASE Double Check My Homework?!?!?! (William Hunter) 17. 08:52 PM - Re: Contactor orientation (Robert L. Nuckolls, III) 18. 09:37 PM - Re: Re: Can Someone PLEASE Double Check My Homework?!?!?! (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:14:14 AM PST US From: Charlie England Subject: Re: AeroElectric-List: Optima Prius Battery For TIO-540 On Wed, Jul 13, 2016 at 6:54 PM, William Hunter wrote: > Greetings, > > > I am building a Dual Battery/Dual Alternator electrical system for a > single Engine Velocity. The engine is a TIO-540 (turbo) and I notate thi s > because the engine only has 7.3 to one compression pistons so therefore t he > starter motor will not have to fight against the usual 8.3 to 1 > compression. One battery will be mounted in the nose and one battery wil l > be mounted under the back seat. > > > Optima sells a 12V Prius battery that they advertise as =9C38 AH / CCA of > 450 amps / MCA of 575 amps=9D and this battery is only 26 LBS. > > > http://www.optimabatteries.com/en-us/shop/yellowtop/optima-batteries-ds46 b24r-yellowtop-prius-auxiliary-battery/ > > > Concord has a =9CPlatinum Series=9D replacement battery for a Aztec and this > airplane has an IO-540 (with normal compression pistons) and the top of t he > line Concord battery advertises Rated Capacity C1 = 1 hr. rate in amper e > hours 33.00 Cold Cranking Amps 440.0 and it is 33 pounds. > > > Even though my airplane will have two batteries I still want to be able t o > start my 6 banger engine with a single battery. > > > Does the collective wisdom on this forum believe that a singular Prius > battery will be sufficient for the starting of my engine? > > .. > > > THANKS!!! > > > Bill Hunter > > Bill, For perspective, I looked up a Gill flooded cell battery (old style with liquid acid & fill caps) designed many decades ago to crank 'big sixes'. It's also 35AH, but only 250 CCA. http://www.aircraftspruce.com/catalog/elpages/gillg35.php Pretty sure the Optima will crank your 6cyl engine. :-) Most of the AGM (starved electrolyte) batteries have significantly higher CCA than flooded cell batteries with the same 20 hour rating (the '35AH' number, in your case). For example, a lot of us with 4 cyl engines use 'no name' 18AH to 22AH AGM batteries to replace the certified 25AH flooded cell batteries originally used with these engines. Even with significantly lower total energy (~20AH vs 25AH), the AGM battery will spin the engine almost fast enough to taxi the plane. :-) Reason is, the AGM can deliver more *power*, short term, than a flooded cell battery. Only downside is that if forced to fly on battery power alone, it will run down faster than the 25AH battery. In your case, both batteries have the same AH rating, so should have the same alternator-out endurance. Charlie ________________________________ Message 2 _____________________________________ Time: 06:34:29 AM PST US From: Charlie England Subject: Re: AeroElectric-List: Lay Flat Battery Contactor and Starter Relay On Wed, Jul 13, 2016 at 7:02 PM, William Hunter wrote: > I vaguely remember one of Bob=99s majestic musings that articulatel y > dispelled the long time myth mandating that battery contactors and starte r > relays must be installed vertically against a wall and not installed flat > on a floorboard. My proposed installation of mounting them on a wall is > not going to work and I want to mount them under the back seat against th e > floorboards. > > > Can someone please confirm that my recollection described above is indeed > accurate and I was not just dreaming Bob=99s majestic words?!?!? > > > .. > > > Cheers!!! > > > Bill Hunter > IIRC, one dispelled myth was the idea that if you mounted them upside down, pulling Gs in the plane could open them. The only issue I could see with 'side mounting' would be asymmetrical wear of the guide that the metal 'slug' moves in. Of course, you can always just make a right angle bracket & mount it on the floor, if you want to keep conventional orientation. Charlie ________________________________ Message 3 _____________________________________ Time: 06:46:12 AM PST US Subject: Re: AeroElectric-List: Optima Prius Battery For TIO-540 From: William Hunter Thanks Charlie for validating my thought process!!! Greatly appreciated!!! Bill Hunter On Jul 14, 2016 06:25, "Charlie England" wrote: > > > On Wed, Jul 13, 2016 at 6:54 PM, William Hunter < > billhuntersemail@gmail.com> wrote: > >> Greetings, >> >> >> >> I am building a Dual Battery/Dual Alternator electrical system for a >> single Engine Velocity. The engine is a TIO-540 (turbo) and I notate th is >> because the engine only has 7.3 to one compression pistons so therefore the >> starter motor will not have to fight against the usual 8.3 to 1 >> compression. One battery will be mounted in the nose and one battery wi ll >> be mounted under the back seat. >> >> >> >> Optima sells a 12V Prius battery that they advertise as =9C38 AH / CCA of >> 450 amps / MCA of 575 amps=9D and this battery is only 26 LBS. >> >> >> >> >> http://www.optimabatteries.com/en-us/shop/yellowtop/optima-batteries-ds4 6b24r-yellowtop-prius-auxiliary-battery/ >> >> >> >> Concord has a =9CPlatinum Series=9D replacement battery for a Aztec and this >> airplane has an IO-540 (with normal compression pistons) and the top of the >> line Concord battery advertises Rated Capacity C1 = 1 hr. rate in ampe re >> hours 33.00 Cold Cranking Amps 440.0 and it is 33 pounds. >> >> >> >> Even though my airplane will have two batteries I still want to be able >> to start my 6 banger engine with a single battery. >> >> >> >> Does the collective wisdom on this forum believe that a singular Prius >> battery will be sufficient for the starting of my engine? >> >> .. >> >> >> >> THANKS!!! >> >> >> >> Bill Hunter >> >> Bill, > > For perspective, I looked up a Gill flooded cell battery (old style with > liquid acid & fill caps) designed many decades ago to crank 'big sixes'. > It's also 35AH, but only 250 CCA. > http://www.aircraftspruce.com/catalog/elpages/gillg35.php > > Pretty sure the Optima will crank your 6cyl engine. :-) Most of the AGM > (starved electrolyte) batteries have significantly higher CCA than floode d > cell batteries with the same 20 hour rating (the '35AH' number, in your > case). For example, a lot of us with 4 cyl engines use 'no name' 18AH to > 22AH AGM batteries to replace the certified 25AH flooded cell batteries > originally used with these engines. Even with significantly lower total > energy (~20AH vs 25AH), the AGM battery will spin the engine almost fast > enough to taxi the plane. :-) Reason is, the AGM can deliver more *power* , > short term, than a flooded cell battery. Only downside is that if forced to > fly on battery power alone, it will run down faster than the 25AH battery .. > In your case, both batteries have the same AH rating, so should have the > same alternator-out endurance. > > Charlie > ________________________________ Message 4 _____________________________________ Time: 07:29:17 AM PST US Subject: Re: AeroElectric-List: Lay Flat Battery Contactor and Starter Relay From: William Hunter Hmmmmmm thanks for the info and I will look today to see if I can mount these little buggers on brackets Bill Hunter +1 408-464-1902 On Jul 14, 2016 6:45 AM, "Charlie England" wrote: > > > On Wed, Jul 13, 2016 at 7:02 PM, William Hunter < > billhuntersemail@gmail.com> wrote: > >> I vaguely remember one of Bob=99s majestic musings that articulate ly >> dispelled the long time myth mandating that battery contactors and start er >> relays must be installed vertically against a wall and not installed fla t >> on a floorboard. My proposed installation of mounting them on a wall is >> not going to work and I want to mount them under the back seat against t he >> floorboards. >> >> >> >> Can someone please confirm that my recollection described above is indee d >> accurate and I was not just dreaming Bob=99s majestic words?!?!? >> >> >> >> .. >> >> >> >> Cheers!!! >> >> >> >> Bill Hunter >> > IIRC, one dispelled myth was the idea that if you mounted them upside > down, pulling Gs in the plane could open them. > > The only issue I could see with 'side mounting' would be asymmetrical wea r > of the guide that the metal 'slug' moves in. Of course, you can always ju st > make a right angle bracket & mount it on the floor, if you want to keep > conventional orientation. > > Charlie > ________________________________ Message 5 _____________________________________ Time: 11:12:14 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Contactor orientation I've heard a boat load of narratives and anecdotes concerning contactor orientation in aircraft. Most of the 'advice' goes to the 'whisky barrel' style contactors from White-Rogers and Cole-Hersey. The first time I recall such a story was a OSH back about 1990 . . . an airshow performer showed up at the B&C booth to buy a new starter and contactor. Seems his contactor was stuck and the starter gears chewed up. He hypothesized that g-loads during his show teased the contactor closed followed by a welding of contacts and an engaged starter. In years since, many more tidbits of sage advice on contactor orientation have appeared throughout the OBAM aviation industry. I have yet to put my hands on any failure of hardware that supports any notion of risk due to airframe induced g-loads. The tear-downs I've conducted fall into three primary categories: (1) Wear out. Contactor has been in service a long time. Contacts are worn. No other evidence of stress such as moisture, broken parts, mis-installation. I.e. the thing went to end of service life. (2) Moisture ingress: contacts, springs, plunger, case badly rusted. See: http://tinyurl.com/p2x7fbl (3) Installation/Manufacturing error: Failure to solder coil wires to terminals, main terminals twisted out of alignment during torque-down of terminal nuts, bit of debris between contacts, exposed to gross external moisture, etc. If you think about it, the plunger in a starter contactor mounted on fire wall moves PARALLED to fuselage axis. Mounted terminals up, it takes NEGATIVE g's to close contact. A whisky-barrel battery contactor is already CLOSED any time aircraft is in motion. A transient cross-feed contactor closure presents no potential hazard. In 40+ years of working with these devices, I have yet to see any evidence that supports the widely circulated fears for 'correct' contactor orientation in airplanes. By the way, I've see hundreds of installations of contactors in TC aircraft for ALL orientations . . . I've never heard of it being any kind of 'problem'. If I were going to posit a bit of advice for orientation it would be to mount the whisky barrel contactor CAP DOWN after first PUNCHING a very small hole in the center of the cap. This is for draining moisture that MIGHT get inside if the contactor experiences long periods of condensing moisture and/or splash. Don't drill the hole . . . you may drop a chip into the interior. Having a drain hole can be the bane of your contactor's existence. See photo series at http://tinyurl.com/p2x7fbl Note in particular what appears to be a factory provided drain hole in pictures 10 and 11. At the same time, severity and range of rust on the interior parts along with rust patters on both sides of the cap suggest that this contactor was installed DRAIN up. Short answer: I have yet to identify a justification for recommending a contactor installation orientation with a goal of reducing risk to system due to operational g-loads. Bob . . . ________________________________ Message 6 _____________________________________ Time: 11:26:31 AM PST US Subject: AeroElectric-List: Re: Question OV Crowbar connection in Z16 figure From: "zwakie" Thanks Bob for confirming! -------- Marcel Zwakenberg XS TG || 912ULS || PH-SBR Read this topic online here: http://forums.matronics.com/viewtopic.php?p=458185#458185 ________________________________ Message 7 _____________________________________ Time: 11:43:17 AM PST US From: ARGOLDMAN@aol.com Subject: Re: AeroElectric-List: Contactor orientation I am a little confused about your statement, " If you think about it, the plunger in a starter contactor mounted on fire wall moves PARALLED to fuselage axis..". Although the device moves parallel to the fuselage, that is really a non-issue. even with severe aerobatics. It is when a hard landing occurs that the spring which keeps the contacting mechanism open can be compressed and contact made. The contact mechanism I think a thick washer) and its associated armature have mass. When the aircraft hits the ground it stops its downward movement but momentum makes the contact mechanism and armature continue on its downward movement compressing the spring. Added to that, the aircraft rebounds and not only does the contact mechanism continue to move downward, the shell of the solenoid, being connected to the firewall is now moving upward increasing the possibility that the contactor will contact, until the energy contained in the spring overcomes the closing movement of the contactor---or the contactor actually makes contact, at which the spring disengages it. Actually, if you look at ACS starter solenoid (contactor) you will see that the terminals are on the top of the "can", the lower part is the electromagnet which pulls the armature (connected to the actual contact device) downward to complete the circuit. It has to be held up (open) by a compression spring. The pilot will never notice that this happens save for the possibility of damaged gears which will probably be blamed on something else. Rich In a message dated 7/14/2016 11:13:32 A.M. Pacific Daylight Time, nuckolls.bob@aeroelectric.com writes: I've heard a boat load of narratives and anecdotes concerning contactor orientation in aircraft. Most of the 'advice' goes to the 'whisky barrel' style contactors from White-Rogers and Cole-Hersey. The first time I recall such a story was a OSH back about 1990 . . . an airshow performer showed up at the B&C booth to buy a new starter and contactor. Seems his contactor was stuck and the starter gears chewed up. He hypothesized that g-loads during his show teased the contactor closed followed by a welding of contacts and an engaged starter. In years since, many more tidbits of sage advice on contactor orientation have appeared throughout the OBAM aviation industry. I have yet to put my hands on any failure of hardware that supports any notion of risk due to airframe induced g-loads. The tear-downs I've conducted fall into three primary categories: (1) Wear out. Contactor has been in service a long time. Contacts are worn. No other evidence of stress such as moisture, broken parts, mis-installation. I.e. the thing went to end of service life. (2) Moisture ingress: contacts, springs, plunger, case badly rusted. See: http://tinyurl.com/p2x7fbl (3) Installation/Manufacturing error: Failure to solder coil wires to terminals, main terminals twisted out of alignment during torque-down of terminal nuts, bit of debris between contacts, exposed to gross external moisture, etc. If you think about it, the plunger in a starter contactor mounted on fire wall moves PARALLED to fuselage axis. Mounted terminals up, it takes NEGATIVE g's to close contact. A whisky-barrel battery contactor is already CLOSED any time aircraft is in motion. A transient cross-feed contactor closure presents no potential hazard. In 40+ years of working with these devices, I have yet to see any evidence that supports the widely circulated fears for 'correct' contactor orientation in airplanes. By the way, I've see hundreds of installations of contactors in TC aircraft for ALL orientations . . . I've never heard of it being any kind of 'problem'. If I were going to posit a bit of advice for orientation it would be to mount the whisky barrel contactor CAP DOWN after first PUNCHING a very small hole in the center of the cap. This is for draining moisture that MIGHT get inside if the contactor experiences long periods of condensing moisture and/or splash. Don't drill the hole . . . you may drop a chip into the interior. Having a drain hole can be the bane of your contactor's existence. See photo series at http://tinyurl.com/p2x7fbl Note in particular what appears to be a factory provided drain hole in pictures 10 and 11. At the same time, severity and range of rust on the interior parts along with rust patters on both sides of the cap suggest that this contactor was installed DRAIN up. Short answer: I have yet to identify a justification for recommending a contactor installation orientation with a goal of reducing risk to system due to operational g-loads. Bob . . . ________________________________ Message 8 _____________________________________ Time: 12:03:45 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Speaking of 'drain holes' . . . While I was working at Cessna, back in the dark ages, the single engine cowls were modified to mount onto brackets riveted to the firewall. These brackets were fitted with rubber shock mounts with Dzuse sockets. The idea was to 'float' the cowl off the fuselage structure for reduction of engine noise in the cabin. Emacs! Prior to the floating cowl, a contiguous cowl mounting flange extended forward off the firewall. After the floating cowl upgrade, fielded aircraft began experiencing contactor failures due to moisture ingress. It seems that an airplane getting a cooling rain on a warm day experienced water splash on cowl mounted equipment. A whisky barrel contactor's temperature was dropped by the cool water, internal pressure went down and liquid water was literally sucked inside. The same water had to get back out through successive atmospheric 'breathing' which could take days of cycles. In the mean time, the 100% humidity inside the contactor wreaked havoc with the devices innards. The first attempt to 'fix' the problem involved manual application of epoxy around all the obvious ingress gaps in the enclosure. Not sure what the effectiveness of this fix was but it was not total . . . Any of the tiniest holes still provided a moisture entry point while further restricting egress through atmospheric breathing. Had a similar problem I wrestled with on an amateur radio repeater on the 1200' platform at KTVH, Hutchinson, KS. A brand new Motorola Micor repeater would go off the air every time it rained and stayed off for hours until it dried out. We set out to 'seal' the cabinet but attempts to close it only made things worse . . . the more we 'sealed' the longer it took to dry out. Recalling my observations years earlier at Cessna, we opened the cabinet up. Installed baffled ducts for air inlet and mounted fans to maintain a good positive airflow. The repeater might still go off the air during a really big frog strangler . . . but would be back on minutes after the rain ceased. Moral of the story: Unless your enclosure is HERMETICALLY sealed, then any attempts improve moisture control with goo, glue, gaskets, etc may prove ineffectual if not antagonistic. In the case of the whisky barrel contactor 'drain' hole, I suggest it is more of a VENT hole. It prevents atmospheric cooling inside from reducing pressure and drawing the moisture inside in the first place. That contactor mounted vent hole up was a contactor waiting to be trashed. Mounted vent hole down, it would probably have died of old age having ingested NO liquid water over its lifetime . . . and if it did . . . it would not have risen high enough to wet the innards. It would have been readily ejected during subsequent atmospheric breathings. Bob . . . ________________________________ Message 9 _____________________________________ Time: 12:22:42 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Optima Prius Battery For TIO-540 > > >Even though my airplane will have two batteries I still want to be >able to start my 6 banger engine with a single battery. > >Does the collective wisdom on this forum believe that a singular >Prius battery will be sufficient for the starting of my engine? Many moons ago, B&C did some testing on one of their SMALLER SVLA batteries for cranking a high performance engine on an aerobatic aircraft. As I recall, they performed 5 or 6, 10-blade cranking events before the starter performance began to noticeably flag. Cranking performance has more do to with LOOP RESISTANCE in the wiring path and CONDITION of the battery than with gross battery size. Fitting your airplane with such beastly batteries in a quest for starting performance seems a bit counter-intuitive . . . it is, after all, an airplane. Any increase in empty weight should equate to some highly desired performance gain. Keep in mind that getting your engine started generally uses only a few percent of total stored energy. Just as B&C demonstrated years ago, having an energetic little SVLA battery wired to the starter with low loss wiring and controls proved very adequate to the starting task. If you're planning dual alternator, dual battery with a split bus (Z-14) then battery integrity is very low on the system reliability totem pole. I would go for two of the smallest practical batteries mounted as close to the engine as practical so that their energy is not wasted getting it piped around the airplane. Why the desire to start on one battery? Do you not plan to maintain your batteries with the same due diligence as you would tires, oil changes, fuel in tanks, spark plugs, prop nicks, brake fluid level, etc. etc? With that much engine driven power there is little performance gain to be secured by carrying around a lot of lead. If it were my airplane, I would use two of the smallest practical batteries located as described above. A pair of 18A.h. batteries should be fine. Plan on both batteries for cranking and the either (1) cap check the batteries every 100 hrs or annual with a goal of discarding at 80% of new capacity -OR- (2) put a new battery in the main battery slot every year and move the year-old main battery to the aux battery slot. That way, you have one battery always less than a year old, no battery more than two years old and no need to cap check. The only reason to worry about getting started on one battery is because you don't have the foggiest notion of the condition of either battery. Batteries, PROPERLY MAINTAINED, are the most reliable source of energy in your airplane. Carrying around two, oversized batteries is not a good substitute for knowing their condition. Bob . . . ________________________________ Message 10 ____________________________________ Time: 02:39:22 PM PST US From: "William Hunter" Subject: AeroElectric-List: Can Someone PLEASE Double Check My Homework?!?!?! I am building a dual bus ala'Bob and I am hopeful someone would PLEASE double check my homework. Attached is a picture of what I want to do. Do I have the cables connected to the correct side of the ties? THANKS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! .. Cheers!!! Bill Hunter ________________________________ Message 11 ____________________________________ Time: 03:03:02 PM PST US From: "William Hunter" Subject: RE: AeroElectric-List: Optima Prius Battery For TIO-540 THANKS Bob for your help and thoughts on this!!! Yes.I read your book (multiple times) and yes maintain the batteries and will swap them out every two years whether they need it or not. I bought a flying Velocity and it came with two batteries mounted in the nose. The larger battery is a 54 pound Optima Red Top and the small battery is a 26 pound Power Sonic 26 Ampere Hour 12260 NB. As per your book I am moving one battery to the firewall (closer to the starter) and leaving the other battery in the nose (weight and balance reasons). I am switching the Power Sonic out for a 26 pound Optima Yellow Top AGM Group Size: JIS 46B24R (Prius Battery) and next year the huge Optima Red Top will most likely go with your recommended battery and go with the annual switch program. .. Cheers!!! Bill Hunter From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Thursday, July 14, 2016 12:17 PM Subject: Re: AeroElectric-List: Optima Prius Battery For TIO-540 Even though my airplane will have two batteries I still want to be able to start my 6 banger engine with a single battery. Does the collective wisdom on this forum believe that a singular Prius battery will be sufficient for the starting of my engine? Many moons ago, B&C did some testing on one of their SMALLER SVLA batteries for cranking a high performance engine on an aerobatic aircraft. As I recall, they performed 5 or 6, 10-blade cranking events before the starter performance began to noticeably flag. Cranking performance has more do to with LOOP RESISTANCE in the wiring path and CONDITION of the battery than with gross battery size. Fitting your airplane with such beastly batteries in a quest for starting performance seems a bit counter-intuitive . . . it is, after all, an airplane. Any increase in empty weight should equate to some highly desired performance gain. Keep in mind that getting your engine started generally uses only a few percent of total stored energy. Just as B&C demonstrated years ago, having an energetic little SVLA battery wired to the starter with low loss wiring and controls proved very adequate to the starting task. If you're planning dual alternator, dual battery with a split bus (Z-14) then battery integrity is very low on the system reliability totem pole. I would go for two of the smallest practical batteries mounted as close to the engine as practical so that their energy is not wasted getting it piped around the airplane. Why the desire to start on one battery? Do you not plan to maintain your batteries with the same due diligence as you would tires, oil changes, fuel in tanks, spark plugs, prop nicks, brake fluid level, etc. etc? With that much engine driven power there is little performance gain to be secured by carrying around a lot of lead. If it were my airplane, I would use two of the smallest practical batteries located as described above. A pair of 18A.h. batteries should be fine. Plan on both batteries for cranking and the either (1) cap check the batteries every 100 hrs or annual with a goal of discarding at 80% of new capacity -OR- (2) put a new battery in the main battery slot every year and move the year-old main battery to the aux battery slot. That way, you have one battery always less than a year old, no battery more than two years old and no need to cap check. The only reason to worry about getting started on one battery is because you don't have the foggiest notion of the condition of either battery. Batteries, PROPERLY MAINTAINED, are the most reliable source of energy in your airplane. Carrying around two, oversized batteries is not a good substitute for knowing their condition. Bob . . . ________________________________ Message 12 ____________________________________ Time: 03:29:08 PM PST US Subject: AeroElectric-List: Re: Can Someone PLEASE Double Check My Homework?!?!?! From: "user9253" Do the banded ends of the diodes connect to the positive side of the coils? If so, OK. I can not tell from the picture. The lower right contactor looks like it has an extra diode that connects the two fat terminals together. Is that what it is, a diode? If so, it is in parallel with the contactor and will be destroyed by high current. A schematic would be easier for me to understand than the picture. If the mounting surface vibrates, flexible cables are better than a bus bar. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=458197#458197 ________________________________ Message 13 ____________________________________ Time: 04:10:23 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Contactor orientation >At 01:37 PM 7/14/2016, you wrote: >I am a little confused about your statement, > >" If you think about it, the plunger in a starter >contactor mounted on fire wall moves PARALLED to >fuselage axis..". > >Although the device moves parallel to the fuselage, that is >really a non-issue. even with severe aerobatics. It is when a hard >landing occurs that the spring which keeps the contacting mechanism >open can be compressed and contact made. Okay, the plunger mass moves along the longitudinal axis of the aircraft. All the flight dynamics plots I've observed speak to really big loads along Z-axis, this is the one that breaks the wings off. What is the forcing function that accelerates the fuselage along the X-axis with any degree of robustness in a 'hard' landing? > The contact mechanism I think a thick washer) Not exactly . . . Emacs! > and its associated armature have mass. Yes, but even less than the legacy whisky-barrel contactor . . . Emacs! > When the aircraft hits the ground it stops its downward movement > but momentum makes the contact mechanism and armature continue on > its downward movement compressing the spring. Actually, aircraft Z-axis acceleration is at 90 degrees to the contractor's stroke axis. > Added to that, the aircraft rebounds and not only does the contact > mechanism continue to move downward, the shell of the solenoid, > being connected to the firewall is now moving upward increasing > the possibility that the contactor will contact, until the energy > contained in the spring overcomes the closing movement of the > contactor---or the contactor actually makes contact, at which the > spring disengages it. Assuming contactor closure CAN be achieved with airframe g-loads . . . what do you suppose the duration of closure might be? What is the delay between first application of power to a starter until the pinion gear is extended and gears make contact? Assuming they do make 'contact' what is the behavior of starter's parts? Contactor closure times are at best measured in tens of millisonde. Time from first energization of starter to gear tooth engagement is many tens of milliseconds . . . perhaps as much as 200. When the ring gear tries to drive the starter pinion, the output shaft will spin ahead of motor velocity due to the starter's built in over-run clutch. > > >Actually, if you look at ACS starter solenoid (contactor) you will >see that the terminals are on the top of the "can", the lower part >is the electromagnet which pulls the armature (connected to the >actual contact device) downward to complete the circuit. It has to >be held up (open) by a compression spring. If you study the disassembly photos of an exemplar contactor at . . . http://tinyurl.com/o5turon Energizing this style of contactor LIFTS the armature and pushes a very light moving contact up against the inside of the dome which mounts the contact studs. The return spring resides between the stationary contacts. > >The pilot will never notice that this happens save for the >possibility of damaged gears which will probably be blamed >on something else. You're right. The pilot who bought a new starter and contactor at OSH was unaware that his starter had probably been engaged for the duration of his performance . . . not because of some transient g-loading but more likely from contact welding promoted by low battery voltage. G-loading to contactor mounted on the fire wall isn't even on the right axis for moving the contactor's inner workings. Even if the contactor were mounted upside down . . . maintained a Z-axis g-load induced contact for an interval needed to get the pinion gears extended is problematic. Bob . . . ________________________________ Message 14 ____________________________________ Time: 06:42:02 PM PST US Subject: Re: AeroElectric-List: Re: Can Someone PLEASE Double Check My Homework?!?!?! From: William Hunter Thanks for your kind reply! The top-left contactor is a BNC S701-1 and the bottom-right contactor is a BNC S701-2. I believe the design of the S70 1-1 battery contactor is such that you're supposed to connect the battery positive to the left hand Pole and the electricity flows from left to right. The diode is as delivered and the silver band is to the left Pole. The bottom-right contactor is supposed to be a bus tie... the idea for the system is when the bus tie switch is off (not grounded) then the left-hand electrical system is powering the left bus independently and the right-hand electrical system is powering the right-hand bus independently. When the bus tie switch is turned on (ground introduced) then that bus tie contactor acts as the connection between the left hand system and the right hand system. I do not intend to have the bus tie to automatically close with the starter switch so the question I have is... what Pole do I connect the bus tie switch grounding wire to? THANKS!!! Bill Hunter +1 408-464-1902 On Jul 14, 2016 15:50, "user9253" wrote: > > Do the banded ends of the diodes connect to the positive side of the > coils? If so, OK. I can not tell from the picture. > The lower right contactor looks like it has an extra diode that connects > the two fat terminals together. Is that what it is, a diode? If so, it is > in parallel with the contactor and will be destroyed by high current. A > schematic would be easier for me to understand than the picture. > If the mounting surface vibrates, flexible cables are better than a bus > bar. > > -------- > Joe Gores > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=458197#458197 > > ________________________________ Message 15 ____________________________________ Time: 06:59:46 PM PST US From: Jim Baker Subject: Re: AeroElectric-List: Contactor orientation Not sure if I can find it again but Cessna Pilots Assn had an article on contactors and orientation about a year ago. One of the interesting quirks was the mention of a mislabeled contactor that was routinely installed incorrectly at the factory resulting in several instances of starter engagement many years after the install. I'll see if I can find it again. Jim Baker 405 426 5377 ________________________________ Message 16 ____________________________________ Time: 07:09:58 PM PST US Subject: Re: AeroElectric-List: Re: Can Someone PLEASE Double Check My Homework?!?!?! From: William Hunter Also... since the starter relay is powered by a 12-volt source it I ASS-U-ME it does not matter what side of the relay is the power side and what side goes to the starter motor... is this correct? Bill Hunter Bill Hunter +1 408-464-1902 On Jul 14, 2016 6:33 PM, "William Hunter" wrote: > Thanks for your kind reply! > > The top-left contactor is a BNC S701-1 and the bottom-right contactor is a > BNC S701-2. > > I believe the design of the S70 1-1 battery contactor is such that you're > supposed to connect the battery positive to the left hand Pole and the > electricity flows from left to right. The diode is as delivered and the > silver band is to the left Pole. > > The bottom-right contactor is supposed to be a bus tie... the idea for the > system is when the bus tie switch is off (not grounded) then the left-hand > electrical system is powering the left bus independently and the right-hand > electrical system is powering the right-hand bus independently. > > When the bus tie switch is turned on (ground introduced) then that bus tie > contactor acts as the connection between the left hand system and the right > hand system. > > I do not intend to have the bus tie to automatically close with the > starter switch so the question I have is... what Pole do I connect the bus > tie switch grounding wire to? > > THANKS!!! > > Bill Hunter > +1 408-464-1902 > > On Jul 14, 2016 15:50, "user9253" wrote: > >> >> Do the banded ends of the diodes connect to the positive side of the >> coils? If so, OK. I can not tell from the picture. >> The lower right contactor looks like it has an extra diode that >> connects the two fat terminals together. Is that what it is, a diode? If >> so, it is in parallel with the contactor and will be destroyed by high >> current. A schematic would be easier for me to understand than the picture. >> If the mounting surface vibrates, flexible cables are better than a bus >> bar. >> >> -------- >> Joe Gores >> >> >> >> >> Read this topic online here: >> >> http://forums.matronics.com/viewtopic.php?p=458197#458197 >> >> >> >> >> >> >> >> >> >> >> ________________________________ Message 17 ____________________________________ Time: 08:52:08 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Contactor orientation At 08:50 PM 7/14/2016, you wrote: > >Not sure if I can find it again but Cessna Pilots Assn had an >article on contactors and orientation about a year ago. One of the >interesting quirks was the mention of a mislabeled contactor that >was routinely installed incorrectly at the factory resulting in >several instances of starter engagement many years after the >install. I'll see if I can find it again. Super! I've got good G2 at Cessna . . . it will be interesting to see which parts were involved. Bob . . . ________________________________ Message 18 ____________________________________ Time: 09:37:35 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Can Someone PLEASE Double Check My Homework?!?!?! At 05:20 PM 7/14/2016, you wrote: > >Do the banded ends of the diodes connect to the positive side of the >coils? If so, OK. I can not tell from the picture. The S701-1 and -2 contactors START with the same, 4-terminal, off-the-shelf device. When used as a S702-2, bus tie contactor the schematic looks like this excerpt from Z-14. TWO diodes provide power to energize the contactor from either bus . . . this insures that you can get the cold bus connected to the hot one no matter which is which. The THIRD diode is the legacy coil suppression device. Emacs! A photo of the as-aSsembled product from B&C looks like this: Emacs! The S701-1 contactor is for more rudimentary tasks like battery contactors. Here you only need the coil suppression diode and the schematic looks like this: Emacs! And the finished product looks like this Emacs! 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.