---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 08/19/13: 10 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:37 AM - Re: AeroElectric-List Digest: 11 Msgs - 08/18/13 (Franz Fux) 2. 08:56 AM - Re: Broadcast Radio Bleedover on Transceiver (Martymason) 3. 12:39 PM - Re: Broadcast Radio Bleedover on Transceiver (mike>bentley) 4. 02:05 PM - High voltage AC and faston (jan) 5. 05:49 PM - Re: High voltage AC and faston (Jeff Luckey) 6. 07:49 PM - Re: Re: Failed brownout battery experiment (Robert L. Nuckolls, III) 7. 07:52 PM - Re: Re: Rotax 912 UL alternator drop-out (Robert L. Nuckolls, III) 8. 08:32 PM - Re: Re: Rotax 912 UL alternator drop-out (Paul Kuntz) 9. 08:49 PM - Re: Re: Broadcast Radio Bleedover on Transceiver (Robert L. Nuckolls, III) 10. 10:45 PM - Re: High voltage AC and faston (jan) ________________________________ Message 1 _____________________________________ Time: 12:37:15 AM PST US From: "Franz Fux" Subject: AeroElectric-List: Re: AeroElectric-List Digest: 11 Msgs - 08/18/13 unable to respond to any mail until the 20th of August, ________________________________ Message 2 _____________________________________ Time: 08:56:00 AM PST US Subject: AeroElectric-List: Re: Broadcast Radio Bleedover on Transceiver From: "Martymason" Mike, Your VHF transceiver is amplitude modulated. AM radio is of course amplitude modulated. Broadcast AM stations transmit at 250 to 50,000 watts. Your receiver will detect signals in the low milliwatts. In early days of commercial radio a diode and earphone was all many people used to get reception. That said, look for the interference getting in your earphones through a corroded connection. It can be in a ground or power or signal connection. The corrosion doesn't have to be obvious. Just dissimilar. The intercom might be another entry point. Perhaps a connection from another audio input. Hope this helps. Marty Read this topic online here: http://forums.matronics.com/viewtopic.php?p=407038#407038 ________________________________ Message 3 _____________________________________ Time: 12:39:20 PM PST US Subject: AeroElectric-List: Re: Broadcast Radio Bleedover on Transceiver From: "mike>bentley" I'll have to check all that out when I get back from this trip. Thanks for the input everyone. I'll let you know what happens. -------- Mike Bentley Joplin, MO N5498B Model 4-1200 (Flying) Jabiru 2200 Rotec Aerosport LCH Heads GT Prop Ellison EFS-2 Throttle Body Read this topic online here: http://forums.matronics.com/viewtopic.php?p=407056#407056 ________________________________ Message 4 _____________________________________ Time: 02:05:19 PM PST US From: jan Subject: AeroElectric-List: High voltage AC and faston Hi Bob, We have a discussion at work regarding the suitability of Faston connectors used for high voltage AC systems in mobile applications.? All the best Jan

Hi Bob,

 

We have a discussion at work regarding the suitability of Faston connectors used for high voltage AC systems in mobile applications.?

 

All the best

 

Jan

 

 




________________________________ Message 5 _____________________________________ Time: 05:49:45 PM PST US From: Jeff Luckey Subject: Re: AeroElectric-List: High voltage AC and faston Yes - they are acceptable for 120/240 volt applications.- I think they ha ve a voltage rating of at least 300 volts.=0A=0AWhat is your high AC voltag e mobile application?=0A=0A=0AJeff Luckey=0A=0A=0A_________________________ _______=0A From: jan =0ATo: aeroelectric-list@matro nics.com =0ASent: Monday, August 19, 2013 2:13 PM=0ASubject: AeroElectric-L ist: High voltage AC and faston=0A =0A=0A=0A =0AHi Bob ,=0A-=0AWe have a discussion at work regarding the suitability=0Aof Faston connectors used fo r high voltage AC systems in mobile applications.?=0A-=0AAll the best=0A == ________________________________ Message 6 _____________________________________ Time: 07:49:45 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Failed brownout battery experiment At 08:42 PM 8/17/2013, you wrote: > >Bob, >Thanks for the advice. >I will use 4 AA batteries temporarily and order a DC-DC booster for >a long term solution. Do you think that the DC-DC converter will >come alive and boost the voltage before the starter contactor >energizes the starter motor? >Electronics should be faster than a mechanical device. Yes, the push button simultaneously applies power to the starter contactor and input to the dc-dc converter. The contactor has a pull-in delay on hte order of 5-10 milliseconds . . . plenty of time for the dc-dc converter to wake up. Bob . . . ________________________________ Message 7 _____________________________________ Time: 07:52:57 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Rotax 912 UL alternator drop-out > I see a max load of 10 amps with everything running, so I am > satisfied that the total load is well within the standard Rotax > system capacity. I also observed that the system voltage drops to > 13.5 volts at the 10 amp max load, which seems abnormal. Under > this max load, the alternator dropped out after a few minutes, > indicated by system voltage dropping to around 12.5 volts -- > consistent with fully charged lead-acid battery. The symptoms you observed suggest a temperature sensitive failure mode within the regulator . . . like a connection that opens when the regulator warms up. While a cooling system MIGHT mask this failure, it wouldn't necessarily be a case of overheating beyond rated operating temperatures rather a case of an intermittent connection that is temperature sensitive. Bob . . . ________________________________ Message 8 _____________________________________ Time: 08:32:17 PM PST US Subject: Re: AeroElectric-List: Re: Rotax 912 UL alternator drop-out From: Paul Kuntz Thanks for the input, Bob. Your guess is in line with my own thinking and is consistent with the symptoms. The failure mode seems to be something that was in need of the first long-duration steady load to surface, and then became more consistent over the following several flight hours. I'm optimistic that replacing the regulator will provide a fix without having to make other changes. Paul Kuntz On Mon, Aug 19, 2013 at 7:52 PM, Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > nuckolls.bob@aeroelectric.com**> > > > I see a max load of 10 amps with everything running, so I am satisfied >> that the total load is well within the standard Rotax system capacity. I >> also observed that the system voltage drops to 13.5 volts at the 10 amp max >> load, which seems abnormal. Under this max load, the alternator dropped >> out after a few minutes, indicated by system voltage dropping to around >> 12.5 volts -- consistent with fully charged lead-acid battery. >> > > > The symptoms you observed suggest a temperature sensitive > failure mode within the regulator . . . like a connection > that opens when the regulator warms up. While a cooling > system MIGHT mask this failure, it wouldn't necessarily > be a case of overheating beyond rated operating temperatures > rather a case of an intermittent connection that is > temperature sensitive. > > > Bob . . . > > ________________________________ Message 9 _____________________________________ Time: 08:49:35 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Broadcast Radio Bleedover on Transceiver The demodulation of an AM signal can occur in any non-linear resistance where the radio signal carrier is 'mixed' with the side band energy to produce a carrier +/- SB products which are the audio program material. The necessary non-linearity can be found in a poorly made-up joint where corrosion products behave like a crude rectifier or crystal junction (rusty razor blades have been used to fabricate "fox-hole radio" detectors). To be sure, the resulting audio signals are very tiny . . . largely determined by the Q of the 'tuner', length of antenna, quality of the ground, electrical sensitivity of the transducer (head set) and skill of designer/fabricator for optimizing impedance matches. It has been readily demonstrated that an artfully crafted 'crystal set' can perform rather well and receive even overseas short wave broadcasts. The kind of performance was never demonstrated in the typical crystal set kits and/or merit badge construction projects. Emacs! If one is into SERIOUS crystal radio fabrication for optimized performance, the lowly battery-less radio is likely to appear more like this . . . Emacs! Separate tuners and traps wound with Litz wire, Schottky detectors, and matching transformer to optimize coupling of energy to the headphones. The radio above was a Dx contest winner for the builder. The 'crystal set' that plagues the aircraft audio system has antennas that are too short, tuners of un-measurably low Q, and headset not known for electromechanical efficiency. Hence, the un-welcomed demodulation of AM radio signals is rare . . . often presented when a coax antenna feeder shield becomes disconnected at a connector and the cockpit is flooded with RF from the ship's VHF comm transmitter. This configuration manifests in a feedback squeal only when transmitting. The last time I heard AM demodulation in an aircraft radio was when taxiing about 1/4 mile away from the airport's air traffic control radar. Each sweep of the antenna put short bursts of PRF 'buzz' in the headset as the airplane was painted with high energy RF. Sensitivity to terrestrial AM transmitters is rare. This case (and that presented by the radar) probably has a root cause in poor design of an input stage to an amplifier. The first stage of a microphone amplifier or isolation amplifier input is not effectively filtered for RF suppression. The strong local signal drives the first stage transistor base into non-linear operation and demodulates the signal which is then amplified by downstream electronics. It's improbable (but not impossible) that a corroded joint is root cause. You need to troubleshoot the system to deduce which of the ship's black boxes is affected. I doubt that it is the radio . . . my bet is on the intercom. Shielding wires for affected devices sometimes helps but it's a poor bandaid . . . the elegant fix is usually addition of a capacitor and perhaps and inductor filter to the input circuit of the affected device. Let us know what your findings are as to which device is victim to the high energy RF signals. Bob . . . ________________________________ Message 10 ____________________________________ Time: 10:45:21 PM PST US From: jan Subject: RE: AeroElectric-List: High voltage AC and faston Mobile power generators - I was told that using Faston for AC application was not a good thing due to the line frequency .. i.e. alternating current causing "vibration" in the connector .. I can not see the issue with using a faston connector in this application, providing a quality faston is used - Not a poor quality Chinese copy. I was wondering if aircraft used them in high voltage AC applications ... _____ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Jeff Luckey Sent: 20 August 2013 01:47 Subject: Re: AeroElectric-List: High voltage AC and faston Yes - they are acceptable for 120/240 volt applications. I think they have a voltage rating of at least 300 volts. What is your high AC voltage mobile application? Jeff Luckey _____ From: jan Sent: Monday, August 19, 2013 2:13 PM Subject: AeroElectric-List: High voltage AC and faston Hi Bob , We have a discussion at work regarding the suitability of Faston connectors used for high voltage AC systems in mobile applications.? All the best Jan <="" font="">

Mobile power generators – I was told that using Faston for AC application was not a good thing due to the line frequency .. i.e. alternating current causing “vibration” in the connector ..  I can not see the issue with using a faston connector in this application, providing a quality faston is used – Not a poor quality Chinese copy.

 

I was wondering if aircraft used them in high voltage AC applications …  

 


From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Jeff Luckey
Sent: 20 August 2013 01:47
To: aeroelectric-list@matronics.com
Subject: Re: AeroElectric-List: High voltage AC and faston

 

Yes - they are acceptable for 120/240 volt applications.  I think they have a voltage rating of at least 300 volts.

What is your high AC voltage mobile application?

 

Jeff Luckey


From: jan <jan@claver.demon.co.uk>
To: aeroelectric-list@matronics.com
Sent: Monday, August 19, 2013 2:13 PM
Subject: AeroElectric-List: High voltage AC and faston

 

Hi Bob ,

 

We have a discussion at work regarding the suitability of Faston connectors used for high voltage AC systems in mobile applications.?

 

All the best

 

Jan

 

 

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