AeroElectric-List Digest Archive

Wed 01/22/14


Total Messages Posted: 6



Today's Message Index:
----------------------
 
     1. 07:14 AM - Re: Strobe switches (Robert L. Nuckolls, III)
     2. 07:16 AM - Re: Strobe switches (Robert L. Nuckolls, III)
     3. 08:56 AM - Re: Strobe switches (Charles Brame)
     4. 11:48 AM - Re: Strobe switches (Robert L. Nuckolls, III)
     5. 11:52 AM - Re: Strobe switches (Robert L. Nuckolls, III)
     6. 05:39 PM - Re: Strobe switches (Bill Watson)
 
 
 


Message 1


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    Time: 07:14:00 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Strobe switches
    At 11:27 AM 1/21/2014, you wrote: I experienced a burned out fast-on connector at my fuse panel on the 16AWG strobe power lead between the fuse panel and the switch. My strobe unit was a CreativAir Avi-Pak 60 watt, 4 outlet strobe power suppy intended for experimental aircraft use. Three strobes were connected. There was a 15amp fuse on the unit and a 15amp fuse on the fuse panel. This was on an RV10 and there was somewhere between 10 and 20 feet of 16AWG wire in the switched power circuit. I had difficulty identifying the burned out fast-on connector. The circuit remained intact despite it's inability to carry the required load. In the course of problem determination, I decided to replace the unit. (I later determined that the unit works just fine) Do you still have this 'problem' system? The XPAK604X was cheaper, had more strobe pattern options and used a control circuit which would seem to accomplish what a relay would do. Interesting. I wonder if they 'discovered' the features in their power demands that were so abusive of otherwise perfectly good switches . . . I'm gathering the hardware together to craft a mailable data acquisition system together that I can ship to a willing List member to gather some definitive data on their strobe systems. I'd like to acquire a library of data both from systems that have suffered failures in the power wiring . . . and some that didn't. "When you can measure what you are speaking about, and express it in numbers, you know something about it, when you cannot express it in numbers, your knowledge is of a meager and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts advanced to the stage of science." ---- Lord Kelvin ---- We've been watching these rare but significant events for some years . . . ignorant of the root cause. I'm thinking it's time to get some good numbers. Bob . . .


    Message 2


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    Time: 07:16:02 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Strobe switches
    At 11:32 PM 1/20/2014, you wrote: Bob, et.al., I just replaced my fourth S700-1(or equivalent) strobe switch in about 200 hours of flying time. Both fast on terminals were badly burned as was about an inch of the 18ga. wire attached to the fast on. Charlie, do you want to try the solid state relay? If you do install this relay . . . Emacs! . . . it will offer a plug-n-play port through which we can gather some good numbers when the DAS system goodies I've ordered get here . . . Bob . . .


    Message 3


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    Time: 08:56:49 AM PST US
    From: Charles Brame <chasb@satx.rr.com>
    Subject: Re: Strobe switches
    Bob, Thanks for the response. See my answers to your questions in red below. Charlie Brame RV-6A N11CB San Antonio ------------------------------------------------------------------ Time: 08:24:54 AM PST US From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com> Subject: Re: AeroElectric-List: Strobe switches > The strobe switch is backed up by a 7 amp fuse which is > recommended for the strobe system (Whelen) and it has never popped. > The run of 18 ga. wire is about ten feet. Of all the switches, only > the strobe switch gets real hot after only a few minutes of use. Can you tell where it's getting hot? With this latest switch failure the hot spots were the fast on connectors at the switch, and I did not notice the switch itself getting hot. The switch fast on tabs are externally riveted and became very loose. There is no signs of burning of the switch itself, though something caused the fast on tabs to become loose on the switch body. And both of the connectors (power in and power out) were burned. In one of the previous Carling failures, the switch was fried on the inside, and the switch itself got hot, including the bat handle. The power connector at the power pack is a Molex type pin plug and does not show any heat related distress. The power supply fast on at the fuse panel has also never shown any signs of heating. With a new switch installed, there is no evidence of any hot spots. However, after a period of time, the problem reoccurs. We've had this (and similar) discussions on strobe controls over the years. I am mystified as to how the burning of switches and terminal crimps seems to be concentrated on the strobe systems . . . driven by relatively light protection (7A fuse). > I discovered that B&C now advertises a MilSpec > single pole switch (MS35058-22) that is the equivalent of the > S700-1. Would this MilSpec switch be a viable solution to the strobe switch problem? Your question raises some interesting points. There seems to be something 'different' about the strobe system current draw profile that stresses the centers of highest-resistance in the power path. In the past, we've seen failures at the rivet joints on the switches, contacts within the switches, switch rockers, and less-than-idea crimps on terminals, etc. Yet the RMS or average current remains so low that a relatively fast protective device like a fuse doesn't complain. I would REALLY like to see the current profile on a strobe system that has repeatedly damaged its switch. There's got to be a characteristic unique to strobe supplies (perhaps just this model of supply) that's especially antagonistic to components in the power feeder. Getting to your specific questions. A relay would certainly transfer the stresses away from the switch . . . but any connecting devices in the power path (like crimps) would still see the 'abuse'. It might well be that a switch with molded terminal supports . . . Emacs! . . . would not offer the weaknesses of riveted joints . . . but crimps, threaded fasteners and internal contacts of the switch would still be getting 'hammered'. I do have a proof-of-concept, solid state relay that I'd be pleased to send you. I've like to get it into service on an often-flown airplane and perhaps yours is the best candidate. It appears that the strobes feeder in your airplane would be a good location to try the relay while potentially addressing your specific failure mode. I would be pleased to try your new solid state relay. However, I don't have any test equipment and am not sure I'm smart enough to use it if I had access. But I am open to ideas and suggestions. Do you have access to any test equipment that might measure and record the current waveform impressed on the strobe switch in your airplane? I'm mulling over ideas for getting data of your airplane and then perhaps expanding the investigation to other airplanes to see if we can identify the controlling physics. There are tens of thousands of airplanes flying Carling switches in the strobe power feed path . . . the fact that a few folks here on the List have experienced serial failures of these switches is curious to say the least. In reading some of the other responses, I'd like to clarify the following: My system is a Whelen three light system with a single power pack. There have been no changes or additions to the system as it was received from the manufacturer. All bulbs and flash sequences were factory set and the cables from the power pack to the lights are factory supplied. The system is grounded at the power pack and the ground appears secure. I have seen no evidence of any other over voltage, over amperage damage to any other switches or devices. The regulator (a generic Ford regulator) seems to work as advertised. The strobe system is left on at all times and begins to operate when the master switch is turned on. In other words, the switch is rarely cycled on or off. Bob . . .


    Message 4


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    Time: 11:48:24 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Strobe switches
    At 10:55 AM 1/22/2014, you wrote: Bob, Thanks for the response. See my answers to your questions in red below. Charlie Brame RV-6A N11CB San Antonio ------------------------------------------------------------------ Time: 08:24:54 AM PST US From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com> Subject: Re: AeroElectric-List: Strobe switches The strobe switch is backed up by a 7 amp fuse which is recommended for the strobe system (Whelen) and it has never popped. The run of 18 ga. wire is about ten feet. Of all the switches, only the strobe switch gets real hot after only a few minutes of use. Can you tell where it's getting hot? With this latest switch failure the hot spots were the fast on connectors at the switch, and I did not notice the switch itself getting hot. The switch fast on tabs are externally riveted and became very loose. There is no signs of burning of the switch itself, though something caused the fast on tabs to become loose on the switch body. And both of the connectors (power in and power out) were burned. In one of the previous Carling failures, the switch was fried on the inside, and the switch itself got hot, including the bat handle. The power connector at the power pack is a Molex type pin plug and does not show any heat related distress. The power supply fast on at the fuse panel has also never shown any signs of heating. With a new switch installed, there is no evidence of any hot spots. However, after a period of time, the problem reoccurs. Good data. Thanks. I would be pleased to try your new solid state relay. However, I don't have any test equipment and am not sure I'm smart enough to use it if I had access. But I am open to ideas and suggestions. Understand. Were your airplane sitting at Medicine Lodge Intergalactic Airport, there are a number of whippy tools on my shelf that would get us the data. I've been considering ways to craft a DAS that could be mailed at cheap priority mail rates and be relatively simple to operate. I think I'm close to realizing that goal . . . you can be the first 'victim' . . . It will let us get data from YOUR installation, on the ground and in just a few seconds. It's basically a 1000 samples/second storage 'oscilloscope' that records to a hard drive. In reading some of the other responses, I'd like to clarify the following: My system is a Whelen three light system with a single power pack. There have been no changes or additions to the system as it was received from the manufacturer. All bulbs and flash sequences were factory set and the cables from the power pack to the lights are factory supplied. The system is grounded at the power pack and the ground appears secure. I have seen no evidence of any other over voltage, over amperage damage to any other switches or devices. The regulator (a generic Ford regulator) seems to work as advertised. The strobe system is left on at all times and begins to operate when the master switch is turned on. In other words, the switch is rarely cycled on or off. Also excellent data points. We'll move ahead as if we know what we're doing. Some of the goodies are coming from overseas but I can get the relay out to you this weekend. Shoot me your mailing address. As soon as you and I figure that we're doing a good thing, we'll bicycle the rig around and get data from as many other airplanes as we have willing participants. Bob . . .


    Message 5


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    Time: 11:52:56 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Strobe switches
    Speaking of strobe switch failures, there was a series of exchanges here on the list a few years back where the Lister had experienced a rash of failures . . . which produced an understandable bad taste in his mouth for the Carling switches. Is that individual still on the List or does anyone recall who it was? I would be interesting to know how the problem resolved. Bob . . .


    Message 6


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    Time: 05:39:26 PM PST US
    From: Bill Watson <Mauledriver@nc.rr.com>
    Subject: Re: Strobe switches
    Yes I still have the problem system and would be happy to send to you. Just let me know the address and it's on it's way. No return required. Thanks On 1/22/2014 10:10 AM, Robert L. Nuckolls, III wrote: > <nuckolls.bob@aeroelectric.com> > > At 11:27 AM 1/21/2014, you wrote: > <Mauledriver@nc.rr.com> > > I experienced a burned out fast-on connector at my fuse panel on the > 16AWG strobe power lead between the fuse panel and the switch. My > strobe unit was a CreativAir Avi-Pak 60 watt, 4 outlet strobe power > suppy intended for experimental aircraft use. Three strobes were > connected. There was a 15amp fuse on the unit and a 15amp fuse on the > fuse panel. This was on an RV10 and there was somewhere between 10 and > 20 feet of 16AWG wire in the switched power circuit. > > I had difficulty identifying the burned out fast-on connector. The > circuit remained intact despite it's inability to carry the required > load. In the course of problem determination, I decided to replace > the unit. (I later determined that the unit works just fine) > > Do you still have this 'problem' system? > > The XPAK604X was cheaper, had more strobe pattern options and used a > control circuit which would seem to accomplish what a relay would do. > > Interesting. I wonder if they 'discovered' the > features in their power demands that were so > abusive of otherwise perfectly good switches . . . > > I'm gathering the hardware together to craft a > mailable data acquisition system together that > I can ship to a willing List member to gather > some definitive data on their strobe systems. > > I'd like to acquire a library of data both > from systems that have suffered failures in > the power wiring . . . and some that didn't. > > > "When you can measure what you are speaking about, > and express it in numbers, you know something about > it, when you cannot express it in numbers, your knowledge > is of a meager and unsatisfactory kind; it may be > the beginning of knowledge, but you have scarcely, > in your thoughts advanced to the stage of science." > > ---- Lord Kelvin ---- > > We've been watching these rare but significant > events for some years . . . ignorant of the > root cause. I'm thinking it's time to get some > good numbers. > > > Bob . . . > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > >




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