---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 01/21/14: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 08:24 AM - Re: Strobe switches (Robert L. Nuckolls, III) 2. 08:29 AM - Strobe switches? (Dr. Andrew Elliott) 3. 09:28 AM - Re: Strobe switches (Bill Watson) 4. 10:30 PM - Re: Digital Industrial Scales Outlets (Andrew29) ________________________________ Message 1 _____________________________________ Time: 08:24:54 AM PST US From: "Robert L. Nuckolls, III" 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? 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 was searching B&C for a relay I could use to reroute the strobe >heavy current wire, and discovered that B&C now advertises a MilSpec >single pole switch (MS35058-22) that is the equivalent of the >S700-1. The dimensions appear the same, with screw type connections >rather than fast ons. It ain't cheap, but it would be worth it to >avoid having to frequently replace a burnt out standard switch. >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. 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. Bob . . . ________________________________ Message 2 _____________________________________ Time: 08:29:51 AM PST US From: "Dr. Andrew Elliott" Subject: AeroElectric-List: Strobe switches? Following some FMEA principles might be valuable here, yes? First, you have some evidence that it is *not* a switch problem, since various switch replacements have done nothing to alleviate the issue. Second, many thousands of builders have strobes in their aircraft which have no problems with switches and fast-on wires burning up. Together, these would tell me to look elsewhere for the root cause. Do you have a non-standard strobe power supply? Can you swap it with a friends to see if that makes any difference? Can you bench test it using ground power? Are you using unusual strobe bulbs? Are they the correct bulbs specified for the power supply and fixtures? Are you using an unusual flash pattern? Perhaps with a high duty cycle? Is there any other evidence of higher than expected current flow behind the switch panel? Other switches or wires? Voltage regulator? Is the ground for the strobe circuit solid? FWIW, Andy ------------------------ Andy Elliott, CL:480-695-9568 N601GE/Z601XL/TD/Corvair 555 hrs since 11/08 Web Site Link ________________________________ Message 3 _____________________________________ Time: 09:28:07 AM PST US From: Bill Watson Subject: Re: AeroElectric-List: Strobe switches 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) The CreativAir units are no longer available so I installed a unit from Nova Electronics - XPAK604X 60 watt, 4 outlet strobe power suppy. It is also referred to as a SUPERPAK604X. This unit seems to be intended for emergency vehicle use but is very similar to the CreativAir product, it looks like it is from the same manufacturer with the same dimensions and mounting hardware. However, it can be powered by an unswitched line directly from the power circuit. It is operated thru a separate control circuit. In the RV10 this allowed me to reduce the power circuit from over 10 feet to less than 3 feet. Where the old circuit was warm/hot to the touch, everything is now cool. The XPAK604X was cheaper, had more strobe pattern options and used a control circuit which would seem to accomplish what a relay would do. On 1/21/2014 2:19 AM, B Tomm wrote: > > What about using a relay to switch the strobe current? Use the carling > switch to control the relay. > > Bevan > > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Charles > Brame > Sent: Monday, January 20, 2014 9:33 PM > To: List AeroElectric > Subject: AeroElectric-List: Strobe switches > > --> > > 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. My first two switches > were Carlings from B&C. Based on AeroElectric recommendations made some > years back, I ordered a S700-1 equivalent switch from Honeywell - same > result. Then I tried a switch from DigiKey, same result. I'm back to a > Carling, at least for the short term. I have Carlings for the Nav lights, > Landing and Wig Wag lights and instrument lights, and I have had no problem > with any of them. 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. > > I was searching B&C for a relay I could use to reroute the strobe heavy > current wire, and discovered that B&C now advertises a MilSpec single pole > switch (MS35058-22) that is the equivalent of the S700-1. The dimensions > appear the same, with screw type connections rather than fast ons. It ain't > cheap, but it would be worth it to avoid having to frequently replace a > burnt out standard switch. Would this MilSpec switch be a viable solution to > the strobe switch problem? > > Charlie Brame > RV-6A, N11CB > San Antonio > > ________________________________ Message 4 _____________________________________ Time: 10:30:40 PM PST US Subject: AeroElectric-List: Re: Digital Industrial Scales Outlets From: "Andrew29" I also buy different products from Ebay and Amazon .But almost all the scale companuy directly offer a range of scale on their website. And you can easily buy scale form their online store at really cheap price. Because in this way you can save the middle man cost. 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