---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 01/14/09: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:13 AM - Shielded wiring (Robert L. Nuckolls, III) 2. 04:22 PM - Using a key Ignition switch with a Rotax 912 (Les Goldner) 3. 04:51 PM - Re: Using a key Ignition switch with a Rotax 912 (Richard Girard) 4. 05:10 PM - Re: Using a key Ignition switch with a Rotax 912 (Floyd) 5. 05:27 PM - Re: Using a key Ignition switch with a Rotax 912 (John Morgensen) 6. 05:46 PM - Honeywell Switch Info TL, NT,TS Series (Chris) ________________________________ Message 1 _____________________________________ Time: 07:13:09 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Shielded wiring At 09:19 PM 1/13/2009 -0700, you wrote: >Sorry it wasn't you. I read it on page 191 fig 7 of "Firewall >Forward" by Tony Bingelis. >Do I understand correctly that only one end the shield of a shielded >cable, like from the Bat. terminal of the alternator, should be grounded. You should join us on the AeroElectric-List. The real rule for shields is follow the manufacturer's instructions. The designer is free to use shields for tasks OTHER than breaking an electro-static noise coupling mode. Folks are fond of parroting rules of one kind or another . . . but are generally not conversant in the physics of how shields work and the variety of additional tasks to which shield may be applied. You will find no shields on my z-figures other than those which are useful . . . and they will show which ends are connected and to what. If you have shielded wire on your alternator, know that it doesn't hurt anything . . . but doesn't help anything either. >I have enjoyed you web site although sometimes I find it hard to >locate what I'm looking for. I'm sure I'll get the hang of it with >more experience. It's not well organized. Suggest you use the google search option to look for words and phrases. I'm working on a bunch of indexing pages to update the website. We're pre-occupied right now with getting two households moved to Medicine Lodge, KS and two houses in Wichita sold. I'll have a lot more time to update the website this spring/summer. Bob . . . ----------------------------------------) ( . . . a long habit of not thinking ) ( a thing wrong, gives it a superficial ) ( appearance of being right . . . ) ( ) ( -Thomas Paine 1776- ) ---------------------------------------- ________________________________ Message 2 _____________________________________ Time: 04:22:49 PM PST US From: "Les Goldner" Subject: AeroElectric-List: Using a key Ignition switch with a Rotax 912 I know it is not the best idea to use an off the shelf inexpensive duel ignition switch with a key because of the possibility of the switch failing. However, given the ease of use and (limited) security feature, I chose to use such a keyed switch. Now I am being told that it is a particularly bad idea to use this type of switch on a Rotax 912 engine because a lot more current passes through the switch with a Rotax 912 than with a Continental or Lycoming. I was also told that this current far exceeds the current that these switches were designed for. Does anyone know if this information is true? I don't want to have to lie upside down under may panel for a few hours pulling out the darn switch if this is just an old wife's tale. Les ________________________________ Message 3 _____________________________________ Time: 04:51:08 PM PST US From: "Richard Girard" Subject: Re: AeroElectric-List: Using a key Ignition switch with a Rotax 912 Les, Check the 912 installation manual, but I think you're the victim of an OHFT (old hangar flying tale, let's just leave the wives out of this :-} Rick On Wed, Jan 14, 2009 at 6:20 PM, Les Goldner wrote: > I know it is not the best idea to use an off the shelf inexpensive duel > ignition switch with a key because of the possibility of the switch failing. > However, given the ease of use and (limited) security feature, I chose to > use such a keyed switch. > > Now I am being told that it is a particularly bad idea to use this type of > switch on a Rotax 912 engine because a lot more current passes through the > switch with a Rotax 912 than with a Continental or Lycoming. I was also told > that this current far exceeds the current that these switches were designed > for. > > Does anyone know if this information is true? I don't want to have to lie > upside down under may panel for a few hours pulling out the darn switch if > this is just an old wife's tale. > > Les > > * > > ________________________________ Message 4 _____________________________________ Time: 05:10:27 PM PST US From: "Floyd" Subject: Re: AeroElectric-List: Using a key Ignition switch with a Rotax 912 Les, I am not sure how the Rotax works but here is what I did for a Continental. I used two toggle switches with OFF-ON-monentary ON position for my mags and start function.. I wired the two Monentary ON in series then to an external starter relay. Thus the toggles only see the small current needed for the relay. I have to hold both switches in the Momentary ON position to engage the starter and when I tun lose, they go to the ON positions for the individual mags. I do not have a key in the ignition system but I doubt anyone could figure out how to start the plane and it is well insured. Besides, the plane is in a locked hangar. I am sure you could do the same and have your key switch to control a relay that controls the starter. This is how the TC aircraft work. You may also consider a "starter engaged" light to let you know if the starter relay ever sticks closed. Floyd Wilkes 601XL Flying and having a wonderful time. ----- Original Message ----- From: Les Goldner To: aeroelectric-list@matronics.com Sent: Wednesday, January 14, 2009 6:20 PM Subject: AeroElectric-List: Using a key Ignition switch with a Rotax 912 I know it is not the best idea to use an off the shelf inexpensive duel ignition switch with a key because of the possibility of the switch failing. However, given the ease of use and (limited) security feature, I chose to use such a keyed switch. Now I am being told that it is a particularly bad idea to use this type of switch on a Rotax 912 engine because a lot more current passes through the switch with a Rotax 912 than with a Continental or Lycoming. I was also told that this current far exceeds the current that these switches were designed for. Does anyone know if this information is true? I don't want to have to lie upside down under may panel for a few hours pulling out the darn switch if this is just an old wife's tale. Les ________________________________ Message 5 _____________________________________ Time: 05:27:22 PM PST US From: John Morgensen Subject: Re: AeroElectric-List: Using a key Ignition switch with a Rotax 912 I wasn't going to use a key at all but decided that the appearance of a (limited) security feature was a good thing. I used a marine ignition switch off-run-(start) with the only the (start) position used for the engine starter. I am planning on using the "run" position to activate the APRS tracking radio. Turning to "off" and pulling out the key has zero effect the electronics or a running engine. john Les Goldner wrote: > > I know it is not the best idea to use an off the shelf inexpensive > duel ignition switch with a key because of the possibility of the > switch failing. However, given the ease of use and (limited) security > feature, I chose to use such a keyed switch. > > Now I am being told that it is a particularly bad idea to use this > type of switch on a Rotax 912 engine because a lot more current passes > through the switch with a Rotax 912 than with a Continental or > Lycoming. I was also told that this current far exceeds the current > that these switches were designed for. > > Does anyone know if this information is true? I dont want to have to > lie upside down under may panel for a few hours pulling out the darn > switch if this is just an old wifes tale. > > Les > > * > * ________________________________ Message 6 _____________________________________ Time: 05:46:39 PM PST US From: "Chris" Subject: AeroElectric-List: Honeywell Switch Info TL, NT,TS Series Some FYI for folks, I took interest in the Honeywell TL switches after reading about the possible issues with Carling etc. So looking at the data sheets I went looking for the TL's with fast-ons or as they say quick connect. They are a rare breed. I emailed Honeywell and below is their reply. Seems to be unobtanium. Anyone know why? Is it because they are quick connect and Honeywell believes screw terminals are what most aerospace folks order? I had ordered an NT series (USA country of origin on package) , a TS series (china country of origin), and also an NKK switch (Japan country of origin) from Digikey to look at them to see if they passed my "looks and feels like a quality product I want in my airplane" test. I was probably most impressed with the NT switch followed by the NKK switch, then the TS switch. I noticed a more solid type rivet on the quick connect on the NKK and NT switch where the TS switch had more dimpled looking rivet like I saw on the pictures of the Carling switches. So if you want TL's right away you need to get them with screw terminals. Probably ground well covered before...but I just thought I would share some of my newbie trip down the electrical yellow brick road... Chris Lucas RV-10 ----- Original Message ----- From: "Sc, Info" Cc: "Sc, Info" Sent: Wednesday, January 14, 2009 3:45 PM Subject: RE: 1TL91 Series Switch Source Thank you for your interest in Honeywell Sensing and Control Products. The 1TL91/2TL91 series is shown on our website: http://sensing.honeywell.com/index.cfm?Ntt=1TL91*&Ntk=si_all_products&ci _id=154286&la_id=1&x=2&y=3 The 1TL91 series is not a stock item at the factory, nor at our Authorized Distributors. We do offer the 1NT/2NT Series that is readily available from our Authorized Distributors. Attached is engineer documents for the 1NT91/2NT91 series for your to review. 4 SPST On Off 1TL91-2 or 1NT91-2 1 SPST (on) off (on) 1TL91-7 or 1NT91-7 2 DPDT On Off not released, so for DPDT unit with Q.C. terminals we have the 2NT91-2 Please use our Sales and Service Locator at the following website to find the Authorized Distributor that can provide you price and delivery information. http://sensing.honeywell.com/index.cfm?ci_id=154022&la_id=1 If you have any further questions, or need any other assistance, do not hesitate to contact us. Honeywell International Inc. Sensing and Control Division Customer Response Center Phone: 1-800-537-6945 International: 815-235-6847 Fax: 815-235-6545 E-Mail: info.sc@honeywell.com Website: www.honeywell.com/sensing/ ------------------------------------------------------------------------------------- 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.