AeroElectric-List Digest Archive

Mon 11/04/13


Total Messages Posted: 14



Today's Message Index:
----------------------
 
     0. 12:04 AM - Please Make A Contribution To Support Your Lists (Matt Dralle)
     1. 11:06 AM - Re: Contactors (Robert L. Nuckolls, III)
     2. 11:06 AM - Re: Contactors (Sacha)
     3. 11:08 AM - Re: Contactors (Robert L. Nuckolls, III)
     4. 11:19 AM - Re: CONTACT EXTRACTOR (Robert L. Nuckolls, III)
     5. 11:21 AM - Re: Re: Trusting a chargers reputation, what an idiot! (Robert L. Nuckolls, III)
     6. 12:12 PM - Re: CONTACT EXTRACTOR (racerjerry)
     7. 12:42 PM - Re: Re: Trusting a chargers reputation, what an idiot! (Roger & Jean)
     8. 03:51 PM - Re: Re: CONTACT EXTRACTOR (Robert L. Nuckolls, III)
     9. 05:15 PM - Re: Re: CONTACT EXTRACTOR (Ken)
    10. 05:51 PM - When is 2AWG not 2AWG? (donjohnston)
    11. 06:39 PM - Re: When is 2AWG not 2AWG? (Robert L. Nuckolls, III)
    12. 06:45 PM - Re: When is 2AWG not 2AWG? (donjohnston)
    13. 09:16 PM - Re: Re: Trusting a chargers reputation, what an idiot! (Bob Verwey)
 
 
 


Message 0


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    Time: 12:04:59 AM PST US
    From: Matt Dralle <dralle@matronics.com>
    Subject: Please Make A Contribution To Support Your Lists
    Dear Listers, There is no advertising income to support the Matronics Email Lists and Forums. The operation is supported 100% by your personal Contributions during the November Fund Raiser. Please make your Contribution today to support the continued operation and upgrade of these services. You can pick up a really nice gift for making your Contribution too! You may use a Credit Card or Paypal at the Matronics Contribution Site here: http://www.matronics.com/contribution or, you can send a personal check to the following address: Matronics / Matt Dralle 581 Jeannie Way Livermore, CA 94550 Thank you in advance for your generous support! Matt Dralle Matronics Email List and Forum Administrator


    Message 1


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    Time: 11:06:36 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Contactors
    At 03:16 AM 11/2/2013, you wrote: ><peter@sportingaero.com> > >There is a potential problem in using only the starter contactor to >switch the starter motor power - those contactors are known to >occasionally weld themselves together. In that case, with only the >starter contactor switching power to the starter, there is then no >way of disengaging it from the running engine until the battery is flat This was a greater risk when starter contactors were intermittent duty versions of the battery contactors (large surface area, low pressure). The modern automotive contactor is a low area, very high pressure connection. These CAN stick but probably not if the battery is good. Too many batteries are flogged until they don't crank the engine any more . . . they've been unsuited for use on an airplane for some period of time before a soggy battery makes a 'soft closure' of a contactor and causes it to stick. > (if that ever happens as the starter is now a generator). Doesn't happen. Every starter has a disconnect mechanism that prevents a running engine from back-driving the starter. Consider that a starter armature runs at or near it's max horsepower rpm while cranking an engine at ~200 rpm. An engine running at 2000 rpm would drive a starter at 10x it's rated running speed . . . throws windings and/or tears up gearboxes. > In the UK the authorities insist that a light is installed in the > panel warning the pilot the starter remains energised, as there > have been several accidents. The engaged starter saps a large > amount of power from the engine and gets very hot, with unpleasant > consequences. Yes, the starter does continue to run from due to applied electrical energy. These are NOT efficient motors. They draw substantial current even when no mechanically loaded. Given their design goals for intermittent duty operation, they simply cannot reject internal heat generated while running unloaded Keep the battery in good shape and starter contactor sticking is very rare. Starter energized light is a simple hedge against taxiing out with a starter energized. Having a battery contactor carry starter current is a pretty cheap insurance. Bob . . .


    Message 2


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    Time: 11:06:38 AM PST US
    From: "Sacha" <uuccio@gmail.com>
    Subject: Contactors
    Being able to pull the mixture control whilst on the ground will stop the engine from producing power, but if the start motor is still energised due to the failed contactor, won't it keep cranking until you pull a terminal off the battery? I'm not that familiar with the starters used in aviation (I hand-swing my engine), so am unsure if they have a disengage mechanism like they do on cars. Hi Etienne, I'm not really sure either. But in any case it sounds manageable enough (though maybe expensive if the starter motor gets wrecked) if one is on the ground. By the way I stuck a loop-type ammeter on the ground cable today and set it to the MAX function and then got in and cranked away. I usually put the electric fuel pump on for 10 seconds before I start the engine and it usually starts immediately. This time I left the fuel pump off so I needed to crank the engine four or five times before it started. The maximum recorded current was 99.6 amps, i.e. 100A. Outside temp was 15C. I'm thinking that my automotive 70A relay might even take this kind of current if I decided to run the starter current through it since it's such a short amount of time. Or I could mount two 70A relays in parallel (total coil current would still only be 0.7 amps), but honestly I'm not sure it would be worth the hassle. What do people think? Sacha


    Message 3


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    Time: 11:08:52 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Contactors
    > > >I couldn't find anything there unfortunately. The starter motor just >has one terminal for the fat positive wire. Rotax starter doesn't have a contactor/solenoid combo. Rotax uses a simple external contactor to control power to the motor. The pinion gear is extended inertially on spiral grooves cut into the motor shaft. Recommend you have either a battery contactor or manually operated battery switch. Bob . . .


    Message 4


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    Time: 11:19:26 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: CONTACT EXTRACTOR
    At 10:09 AM 11/3/2013, you wrote: <gki@suffolk.lib.ny.us> > >Can someone give me the (working tip end) >dimensions of the Bendix/King contact extraction >tool p/n 047-05099-001 that is used to remove >contacts p/n 030-01107-00xx as used on KT 76 and >KX 155. Please =93 no guesses =93 I need a >caliper on this one. I will be working under extremely difficult conditions. > >Apparently, this tool is also known as Molex p/n HT-1884 >Thank you for your help. How many terminals do you need to extract? The tool size is not critical . . . it needs to fit inside the width of the slot in the connector housing and be no thicker than the depth of the slot. It's a thin blade that is used to depress the retention tang on the pin. Emacs! Unless you have bunch of terminals to pull, suggest you try a sewing needle inserted into the center of the slot. The tang is only about .4" inside and not hard to reach. Bob . . .


    Message 5


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    Time: 11:21:28 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Trusting a chargers reputation, what an idiot!
    At 07:55 AM 11/2/2013, you wrote: > > > > the battery is 13.4 and the MGL Efis shows supply voltage as > 12.9. I have checked all feeds and connectors, but cannot isolate > the voltage drop.... > >Subtracting 12.9 from 13.4 equals 0.5 volts which is the voltage >drop across a diode. Is the MGL EFIS powered through an E-Bus >diode? What happens when the E-Bus alternate feed path (if >installed) is turned on? >Joe Excellent question!!!! Bob . . .


    Message 6


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    Time: 12:12:38 PM PST US
    Subject: Re: CONTACT EXTRACTOR
    From: "racerjerry" <gki@suffolk.lib.ny.us>
    Bob, Thank you for your response. Fortunately, I have only two terminals to extract. I was hoping to get measurements of the actual tool; especially the blade thickness, so the contact would release easily, yet I wouldnt have to worry about permanently deforming the retainer clip. Also, I dont have a spare Bendix/King card edge connector body to give me the slot width, but I could probably guesstimate that. My idea was to cut a sliver of shim stock. Do YOU have a guess as to blade thickness of this tool? Yes, I may have to resort to the sewing needle approach, but I dont know if these old eyes will be able to keep the needle centered in the slot. Besides, trying different sizes, I can ruin only so many of my wifes sewing needles before there is hell to pay. Thanks again, Jerry King -------- Jerry King Read this topic online here: http://forums.matronics.com/viewtopic.php?p=412114#412114


    Message 7


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    Time: 12:42:36 PM PST US
    From: "Roger & Jean" <mrspudandcompany@verizon.net>
    Subject: Re: Trusting a chargers reputation, what an idiot!
    > the battery is 13.4 and the MGL Efis shows supply voltage as >> 12.9. I have checked all feeds and connectors, but cannot isolate >> the voltage drop.... Were you able to measure the voltage at the connector going into the EFIS? If this measures at 13.4V, then you may have a calibration error in your EFIS. Roger


    Message 8


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    Time: 03:51:32 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: CONTACT EXTRACTOR
    At 02:11 PM 11/4/2013, you wrote: > >Bob, Thank you for your response. Fortunately, >I have only two terminals to extract. >I was hoping to get measurements of the actual >tool; especially the blade thickness, so the >contact would release easily, yet I wouldnt >have to worry about permanently deforming the retainer clip. There is possibility of 'flattening' the clip even when the 'right tool' is used. I always tweak the clip to increase it's grip before re-inserting a used terminal back into the housing. > Also, I dont have a spare Bendix/King card > edge connector body to give me the slot width, > but I could probably guesstimate that. I don't think I've ever actually measured one. The last two that I made were fabricated from flat spring stock cabbaged from a pocket tape measure. I used a cutoff wheel in a Dremel to sculpt the material. Many moons ago I published this offering Vhttp://tinyurl.com/nknv4bk I believe these numbers were suited to the various versions of this pin retention methodology . . . but that was some time ago. >Yes, I may have to resort to the sewing needle >approach, but I dont know if these old eyes >will be able to keep the needle centered in the >slot. Besides, trying different sizes, I can >ruin only so many of my wifes sewing needles before there is hell to pay. Get your own needles. In fact, I think sewing machine needles are about the right thickness and they offer a 'handle' of sorts on the machine end. Again, a little sculpting with a Dremel would tailor them to the task. Bob . . .


    Message 9


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    Time: 05:15:11 PM PST US
    From: Ken <klehman@albedo.net>
    Subject: Re: CONTACT EXTRACTOR
    I find that one of my very small flat screwdrivers (watchmaker type) often works well on these types of pins. Ken On 04/11/2013 6:50 PM, Robert L. Nuckolls, III wrote: > <nuckolls.bob@aeroelectric.com> > > At 02:11 PM 11/4/2013, you wrote: >> <gki@suffolk.lib.ny.us> >> >> Bob, Thank you for your response. Fortunately, I have only two >> terminals to extract. >> I was hoping to get measurements of the actual tool; especially the >> blade thickness, so the contact would release easily, yet I wouldnt >> have to worry about permanently deforming the retainer clip. > > There is possibility of 'flattening' the > clip even when the 'right tool' is used. > I always tweak the clip to increase it's > grip before re-inserting a used terminal > back into the housing. > >> Also, I dont have a spare Bendix/King card edge connector body to >> give me the slot width, but I could probably guesstimate that. > > I don't think I've ever actually measured one. > The last two that I made were fabricated from > flat spring stock cabbaged from a pocket tape > measure. I used a cutoff wheel in a Dremel to > sculpt the material. > > Many moons ago I published this offering > > Vhttp://tinyurl.com/nknv4bk > > I believe these numbers were suited to > the various versions of this pin retention > methodology . . . but that was some time ago. > > >> Yes, I may have to resort to the sewing needle approach, but I dont >> know if these old eyes will be able to keep the needle centered in the >> slot. Besides, trying different sizes, I can ruin only so many of my >> wifes sewing needles before there is hell to pay. > > Get your own needles. In fact, I think > sewing machine needles are about the right > thickness and they offer a 'handle' of sorts > on the machine end. Again, a little sculpting > with a Dremel would tailor them to the task. > > > Bob . . . > > --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com


    Message 10


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    Time: 05:51:49 PM PST US
    Subject: When is 2AWG not 2AWG?
    From: "donjohnston" <don@velocity-xl.com>
    I purchased some 2AWG welding cable from McMaster-Carr. But the 2AWG ring terminals are too big. After trying all the ring terminals in my collection, the ones that fit are for 4AWG. Does welding cable have a smaller diameter than... regular wire? Read this topic online here: http://forums.matronics.com/viewtopic.php?p=412123#412123


    Message 11


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    Time: 06:39:48 PM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: When is 2AWG not 2AWG?
    At 07:51 PM 11/4/2013, you wrote: > >I purchased some 2AWG welding cable from McMaster-Carr. But the 2AWG >ring terminals are too big. After trying all the ring terminals in >my collection, the ones that fit are for 4AWG. > >Does welding cable have a smaller diameter than... regular wire? The standard for sizing wire is predicated on the cross-section of copper . . . so a 10AWG SOLID wire will be a tad smaller in diameter than STRANDED wire due to the included air-space between strands. As a general rule, copper wires can be counted on to be as-advertised. Aluminum wire has a slightly higher resistance. Assuming that it is marked for AWG equivalency, then a 2AWG aluminum wire would be decidedly larger than it's copper cousin. Terminals are another matter. You cannot know the tooling for which the terminal was designed . . . which may indeed bring a 'too big' terminal down to size with the right squish. So pick the terminal with the tightest practical fit and then close the gap with wedges/solder or judicious application of force. The 'rating' for wire is more consistent and reliable than the sizing of terminals. Bob . . .


    Message 12


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    Time: 06:45:51 PM PST US
    Subject: Re: When is 2AWG not 2AWG?
    From: "donjohnston" <don@velocity-xl.com>
    Thanks! :) Read this topic online here: http://forums.matronics.com/viewtopic.php?p=412126#412126


    Message 13


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    Time: 09:16:13 PM PST US
    From: Bob Verwey <bob.verwey@gmail.com>
    Subject: Re: Trusting a chargers reputation, what an idiot!
    I run a wire direct from the Bat bus to the EFIS CB (2 amp) then via a switch to the EFIS. Sooooo, thinking out loud, it can only be the CB or the switch causing the voltage drop? My master switch is one of those manual types recently discussed on the list. All parts brand new, but worth checking! I imagine a .5v volt drop across the master could turn exiting once the starter starts pulling 200 amps! Best... Bob Verwey On 4 November 2013 21:20, Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > nuckolls.bob@aeroelectric.com> > > At 07:55 AM 11/2/2013, you wrote: > >> >> >> > the battery is 13.4 and the MGL Efis shows supply voltage as 12.9. I >> have checked all feeds and connectors, but cannot isolate the voltage >> drop.... >> >> Subtracting 12.9 from 13.4 equals 0.5 volts which is the voltage drop >> across a diode. Is the MGL EFIS powered through an E-Bus diode? What >> happens when the E-Bus alternate feed path (if installed) is turned on? >> Joe >> > > Excellent question!!!! > > > Bob . . . > >




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