---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 05/02/19: 12 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:08 AM - Re: TWISTED PAIRS (John M Tipton) 2. 02:11 AM - Re: TWISTED PAIRS (John M Tipton) 3. 02:30 AM - Re: TWISTED PAIRS (user9253) 4. 06:06 AM - Re: TWISTED PAIRS (Robert L. Nuckolls, III) 5. 06:26 AM - Re: Re: TWISTED PAIRS (Robert L. Nuckolls, III) 6. 07:19 AM - Re: TWISTED PAIRS (Ernest Christley) 7. 07:54 AM - Re: TWISTED PAIRS (Robert L. Nuckolls, III) 8. 11:33 AM - Re: ovm (skywagon185guy) 9. 05:08 PM - GRT EIS Issues When Transmitting () 10. 05:11 PM - Re: ovm (Robert L. Nuckolls, III) 11. 05:47 PM - Re: ovm (Charlie England) 12. 05:58 PM - Re: TWISTED PAIRS (Art Zemon) ________________________________ Message 1 _____________________________________ Time: 02:08:37 AM PST US Subject: AeroElectric-List: Re: TWISTED PAIRS From: "John M Tipton" Hi Bob Here is an example of twisted pairs (even twisted trio) you asked for my EZpilot (A/p): file:///C:/Users/John%20Tipton/Downloads/EZ%20Pilot%20Manual%20rev%202.5%20.pdf I hope that works and it on page 36: Regards John Read this topic online here: http://forums.matronics.com/viewtopic.php?p=489049#489049 ________________________________ Message 2 _____________________________________ Time: 02:11:50 AM PST US Subject: AeroElectric-List: Re: TWISTED PAIRS From: "John M Tipton" Hi Bob Try this: https://www.trioavionics.com/EZ%20Pilot%20Manual%20rev%202.5%20.pdf Page 36 John Read this topic online here: http://forums.matronics.com/viewtopic.php?p=489050#489050 ________________________________ Message 3 _____________________________________ Time: 02:30:07 AM PST US Subject: AeroElectric-List: Re: TWISTED PAIRS From: "user9253" John, The link that you posted points to a file on your hard drive. Below is a link to the EZ Pilot Operation and Installation Manual on Trio Avionics website: https://www.trioavionics.com/EZ%20Pilot%20Manual%20rev%202.5%20.pdf -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=489051#489051 ________________________________ Message 4 _____________________________________ Time: 06:06:54 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: TWISTED PAIRS At 06:18 PM 5/1/2019, you wrote: > >Doesn't the remote panel switch for ELTs generally specify the use of >twisted-pair wiring? Seems like I recall seeing that when I was >considering replacing my ELT. Could be . . . and I too have suggested it for situations where one is building a long run of 2 or more wires. I've often used a drill motor to build an independent bundle of wires, usually small (22 or 20AWG max) that all terminated in the same place. Twisting is, at best, a matter of craftsmanship/convenience. A bundle of wires in a 'straight lay' is stiff while a twisted array remains flexible while physically constrained in a handy bundle. When building pendant cables for ground test equipment, I often twist the array of wires before pulling them through a 'snake skin' . . . makes for a really compliant test tool. Mitigation of magnetic/electro-static coupling by twisting SEEMS like a good idea . . . except that those coupling modes are exceedingly weak and practical ONLY when the pair to be twisting is either a STRONG potential antagonist or VULNERABLE victim. The DC power leads are NOT potential antagonists nor are they vulnerable. The fact that either of these conditions is a consideration for integrating a particular electro-whizzy into your airplane is a CONFESSION of poor attention to details . . . like Mil-Std-704, DO-160, etc . . . or a lack of understanding. It's like the ol' avionics master switch meme intended to ward off evil, non-existent 'spikes' while cranking an engine. Once planted, it will grow and thrive like an intellectual fungus long after advances in understanding and application of the SCIENCE has shown it to be floobydust. The short answer is: when your electro-whizzy's installation manual calls for twisting for 'noise' or avionics master switch for 'spikes', a healthy dose of skepticism is called for. Bob . . . ________________________________ Message 5 _____________________________________ Time: 06:26:50 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: TWISTED PAIRS At 04:07 AM 5/2/2019, you wrote: > >Hi Bob > >Here is an example of twisted pairs (even twisted trio) you asked >for my EZpilot (A/p): > >file:///C:/Users/John%20Tipton/Downloads/EZ%20Pilot%20Manual%20rev%202.5%20.pdf > >I hope that works and it on page 36: The folks who wrote this did a better than average job, but their lack of experience in air-frame wiring is obvious. The narrative about wire sizes is startling. 24AWG wire in an airframe is more difficult to work with . . . 26AWG would NOT be recommended. I would not suggest such a thing for OBAM aircraft and would think LONG and HARD before calling it out in a TC aircraft. Premier (B390) airframe wiring used a lot of 24 . . . but this was a 'busy' airplane with miles of wire in it. Weight savings was significant. But the people who had to work with it on the line and in the field were less than enthusiastic. Our airplanes (with mere dozens of feet of wire), hooking up with smaller than 22AWG is of no practical benefit. The shielded trios use to wire the servos is handy from a fabrication/ installation perspective. The EMC considerations for using a shielded trio may be (but unlikely) valid. But using off- the-spool, pre-twisted, pre-twisted, shielded wire is very convenient. Bob . . . ________________________________ Message 6 _____________________________________ Time: 07:19:05 AM PST US From: Ernest Christley Subject: Re: AeroElectric-List: TWISTED PAIRS I like to twist power and ground for organizational reasons.=C2- It just cleans up the installation. On Wednesday, May 1, 2019, 5:38:13 PM EDT, Robert L. Nuckolls, III wrote: At 10:43 AM 5/1/2019, you wrote: --> AeroElectric-List messageposted by: "John M Tipton" Hi Guys (Bob) When a twisted pair is required (eg: Power and ground to Radio), do youtake both back to the fuse panel, then lead off the ground wire to theground bl ock=C2- ( which is a return route - L form) or lead off theground wire to the ground block en route (it's only half distance to theground block - ie : T form) To clarify: the route to the ground block is 15 inches and to the Fusebus 3 0 inches. =C2- I can't imagine why anyone would twist =C2- the ground and power wires on any device =C2- (other than the illumination lamp to a =C2- whisky compass up on the windshield). =C2- What's the product and what, if any, reason =C2- is given in instructions for doing this =C2- to the wires? =C2- Bob . . . ________________________________ Message 7 _____________________________________ Time: 07:54:53 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: TWISTED PAIRS At 09:18 AM 5/2/2019, you wrote: >I like to twist power and ground for organizational reasons. It >just cleans up the installation. Hear hear! Bob . . . ________________________________ Message 8 _____________________________________ Time: 11:33:34 AM PST US From: skywagon185guy Subject: Re: AeroElectric-List: ovm Only an assumption, but, I would think that the ovm trip setting should be lower than 16.2 vdc. Maybe in the 15 volt range. It would be great if someone with battery experience details would chime in on how high the charge voltage rate can go before starting to "cook" our aviation type batteries. On Wed, May 1, 2019 at 5:00 AM bobnoffs wrote: > > hi all, > the past 6 months i have spent time looking into ovm's. i have just > completed installation and tested one from perihelion. as the ad says > 'about the size of a domino'. it actuates a relay on the output of my > alternator. instructions and schematics were excellent and eric [owner] was > very helpful. > very simple. at 16.2 volts this unit opens the circuit to the relay coil > and lights up an led on the panel. > bob noffs > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=489034#489034 > > ________________________________ Message 9 _____________________________________ Time: 05:08:01 PM PST US From: Subject: AeroElectric-List: GRT EIS Issues When Transmitting Greeting, I am posting for a friend who fly a Velocityand I will get him to sign up for the Aeroelectric. His Question: I need help with further troubleshooting an anomaly. When I key the radio, all EGT & CHT temps drop about 25 degrees and stay there until the transmission is released at which time they return to normal. This is repeatable with the engine running or not. The EIS has been replaced with a brand new one. I have swapped radios on the antenna. Whichever radio is using the stbd antenna causes the anomaly. I inspected the antenna wire (RG-400) as much as possible without removing it. No wear or nicks. System, both EIS and radios have been flawless since installation in 2016. Have even installed a ferrite sleeve on the cht/egt wire bundle. No change. Transmission and reception on the radio is loud and clear. I have a GRT EIS mounted [at the back of the copilot side of the airplane] on the floor. The wires run through the [fiberglass conduit] to the engine. The closest the antenna gets to the EIS is about 18 inches. Thanks, Bill Hunter ________________________________ Message 10 ____________________________________ Time: 05:11:52 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: ovm At 01:32 PM 5/2/2019, you wrote: >Only an assumption, but, I would think that the >ovm trip setting should be lower than 16.2 vdc. >Maybe in the 15 volt range. >It would be great if someone with battery >experience details would chime in on how high >the charge voltage rate can go before starting >to "cook"=C2 our aviation type=C2 batteries. First of all, OV conditions are first of all rare. Second, they almost never present a 'creeping rise' in bus voltage. OV regulation failures tend to be gross over excitation events that cause an alternator to deliver a constant current (slightly higher than its nameplate rating) with no practical limit to the limit to the alternator's UNLOADED output. The key word is UNLOADED . . . there are ship's accessories on line . . . then there's a battery that will attempt to absorb what energy is left over between alternator ratings and ship's loads. Hence, the voltage doesn't 'creep', rather it will rise at some observable rate over a period of seconds to perhaps a couple of minutes. OV protection systems are generally designed to trip for any ov condition that exceeds 16.0 (32.0) volts for something on the order of 500 milliseconds (The DO-160 stand off value for 20.0/40.0v is 1.0 second). In the exceedingly rare case that your regulator decides to do the creepy thing, it will no doubt be so slow that you'll easily know that something is amiss from observation of ship's various voltage displays. So, Eric's selected calibration point for ov trip is consistent with legacy design goals and very conservative in light of DO-160 qualification protocols along with alternator/battery performance under demonstrated ov stress. Bob . . . ________________________________ Message 11 ____________________________________ Time: 05:47:42 PM PST US Subject: Re: AeroElectric-List: ovm From: Charlie England On 5/2/2019 7:11 PM, Robert L. Nuckolls, III wrote: > At 01:32 PM 5/2/2019, you wrote: >> Only an assumption, but, I would think that the ovm trip setting >> should be lower than 16.2 vdc. >> Maybe in the 15 volt range. >> It would be great if someone with battery experience details would >> chime in on how high the charge voltage rate can go before starting >> to "cook" our aviation type batteries. > > First of all, OV conditions are first of all rare. > Second, they almost never present a 'creeping rise' in > bus voltage. OV regulation failures tend to be > gross over excitation events that cause an > alternator to deliver a constant current > (slightly higher than its nameplate rating) > with no practical limit to the limit to > the alternator's UNLOADED output. > > The key word is UNLOADED . . . there are > ship's accessories on line . . . then there's > a battery that will attempt to absorb what > energy is left over between alternator ratings > and ship's loads. > > Hence, the voltage doesn't 'creep', rather > it will rise at some observable rate over > a period of seconds to perhaps a couple of > minutes. OV protection systems are generally > designed to trip for any ov condition that > exceeds 16.0 (32.0) volts for something > on the order of 500 milliseconds */(The > DO-160 stand off value for 20.0/40.0v is > 1.0 second). > > /* In the exceedingly rare case that your > regulator decides to do the creepy thing, > it will no doubt be so slow that you'll > easily know that something is amiss from > observation of ship's various voltage > displays. > > So, Eric's selected calibration point for > ov trip is consistent with legacy > design goals and very conservative in > light of DO-160 qualification protocols > along with alternator/battery performance under > demonstrated ov stress. > > > Bob . . . > And, if you assume that with a 'modern' panel, the engine monitor will have configurable voltage limits for its alarm circuitry, you can set the hi V alarm point right at the battery's max allowable, get notified if that happening, and avoid nuisance trips by the OVM. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ________________________________ Message 12 ____________________________________ Time: 05:58:05 PM PST US From: Art Zemon Subject: Re: AeroElectric-List: TWISTED PAIRS I didn't twist much of anything. I used red and black wire and laced the bundles. It ended up looking nice and the lacing was peaceful, satisfying work. I did twist the wires for my OAT probe and that was just to make the pair easier to handle since it runs the length of the fuselage. -- Art Z. Sent from my phone. 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