---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Tue 09/12/06: 15 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:23 AM - Fuel sys config, was Fuel Pump Switch(es) (glen matejcek) 2. 05:49 AM - Re: Whelen Strobes Blowing Fuses (Robert L. Nuckolls, III) 3. 07:18 AM - Re: Fuel Pump Switch(es) (Gary Casey) 4. 07:46 AM - Re: Fuel Pump Switch(es) (Hinde, Frank George (Corvallis)) 5. 07:47 AM - Re: Whelen Strobes Blowing Fuses (Peter Braswell) 6. 08:50 AM - Re: Whelen Strobes Blowing Fuses (Matt Prather) 7. 09:05 AM - Re: Whelen Strobes Blowing Fuses (Peter Braswell) 8. 09:48 AM - Re: Fuel Pump Switch(es)Fuel Pump Switch(es)Fuel Pump Switch(es) (John Burnaby) 9. 12:40 PM - Re: Whelen Strobes Blowing Fuses (james wickert) 10. 12:59 PM - Re: AeroElectric-List Digest: 26 Msgs - 09/10/06 (Speedy11@aol.com) 11. 06:18 PM - Re: Alternator Problem - Not in plane (Bob White) 12. 06:18 PM - Re: Whelen Strobes Blowing Fuses (Robert L. Nuckolls, III) 13. 06:18 PM - Re: Fuel Pump Switch(es) (Kevin Horton) 14. 06:29 PM - Re: Whelen Strobes Blowing Fuses (Peter Braswell) 15. 07:02 PM - Re: Whelen Strobes Blowing Fuses (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 05:23:27 AM PST US From: "glen matejcek" Subject: AeroElectric-List: Fuel sys config, was Fuel Pump Switch(es) --> AeroElectric-List message posted by: "glen matejcek" Hello Brian! As ever, you are absolutely correct. My bad. I know better than to use absolutes, especially with this crowd1 On the other hand, the systems you've cited feed from the mains to a header tank at the low point. This arrangement should preclude drawing air from the empty tank. In my RV, the fuel pick up in the tank is the low point in the system. It's all uphill from there, and there is no header tank to buffer the system. To the best of my knowledge, and I cringe as I type the words, there are no certified, low wing singles that will feed simultaneously from multiple tanks other than those equipped with headers. As a point of interest, does anybody out there know of a plane configured that way? >On Mon, 2006-09-11 at 08:57, Bill Denton wrote: >> RE: Kevin, besides all the good points George makes, >> and as someone pointed out a while back on one of these lists, you will >> only find a "BOTH" position on a fuel selector in a high wing single engine >> airplane. > >Well, it is probably not safe to use the words "always", "never", and >"only" when describing systems. As I pointed out earlier, both the >Nanchang CJ6A and Yak-52 are low-wing aircraft that have only an on/off >fuel selector at the firewall. There is no way on either of these >aircraft to select a left or right tank. They are always on "both". > >Brian Lloyd glen matejcek aerobubba@earthlink.net ________________________________ Message 2 _____________________________________ Time: 05:49:53 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Whelen Strobes Blowing Fuses --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:01 PM 9/11/2006 -0400, you wrote: >Gang, >I've got a problem with my Whelen strobe system blowing a 10 amp fuse. > >I'm using a 10 amp mini-blade fuse which is blowing intermittently. The >kit manufacturer as per the instructions, recommends a 10 amp fuse, but of >course they allude to a 10 amp aircraft style reset-able fuse. I can seem >to get the fuse to blow fairly regularly if I turn the strobes on and off >in quick succession. The fuse will blow less reliably if I turn the >strobes on prior to takeoff and just leave them on. > >My questions are these: Would there be any difference in a 10 amp blade >fuse vs. the mechanical breaker style fuse as prescribed by the >manufacturer? And the other question is is there such thing as a slow-blow m How old is this system? Is this a "new" phenomenon that's popped up after a period of satisfactory operation or has it existed from square-one? Have you placed an ammeter in series with the supply line to measure the system's current draw? You need an analog meter to get some notion of minimum and maximum current between firings. Which strobe system is it? >ini blade style fuse and could this possibly make a difference? And >finally perhaps there is something more insidious at work here? Fuses are faster to respond than most breakers. It could be that your strobes are drawing an average well below the 10A rating of the fuse but hit it repeatedly with levels that exceed 10A and degrade the fuse over a period of time. The real definitive measurement would be to put a data acquisition system on it and watch it for a period of time and the compare that data with a system that performs as expected. Unfortunately, most folks in your position don't have access to such equipment and you're stuck with hip-shots hopefully filtered through some sense of the physics. Bob . . . --------------------------------------------------------- < What is so wonderful about scientific truth...is that > < the authority which determines whether there can be > < debate or not does not reside in some fraternity of > < scientists; nor is it divine. The authority rests > < with experiment. > < --Lawrence M. Krauss > --------------------------------------------------------- ________________________________ Message 3 _____________________________________ Time: 07:18:24 AM PST US From: Gary Casey Subject: Re: AeroElectric-List: Fuel Pump Switch(es) I might have missed some of the discussion, but the comment below seems to be directed at the tank valving method - specifically whether to use two separate fuel valves or one, with the recommendation to run all the fuel through one valve. I chose to put two valves on mine for the following reasons: 1. A single valve is a single point of failure - what if the handle breaks off or the valve sticks? The most likely time for that to happen is when one port is being closed off before the other opens (apparently most or all fuel selectors go to "off" between right and left positions). If it jams in this position all fuel is shut off. My on-off valves are completely independent and controlled from their own lever and cable. If one jams either open or shut the other is unaffected. 2. The fuel can be shut off at the tank, not in the middle of the cockpit. When both valves are shut off no fuel can enter the cockpit, which would be reassuring in case of an off-airport landing. 3. It reduces the number of fuel fittings and therefore the number of potential leak paths, especially in the cockpit. 4. It allows the backup electric pump to be placed at the lowest point in the fuel system which should provide the best protection against vapor lock. 5. When switching tanks the new tank can be turned on before the old tank is shut off, guaranteeing a continuous flow of fuel. 6. A trivial one: If the plane is landed with an unbalanced fuel load, both valves can be left on, equalizing the fuel load before the next flight. The disadvantage is that both valves could be inadvertently turned on, which on a low-wing plane means that if one tank is run dry in that condition the engine could draw air. In that case one fuel gage would read empty and changing the fuel valve positions (shutting off the empty tank) would correct the condition. Interestingly, my DAR was skeptical about the arrangement, but was satisfied by the placement of a placard "continuous operation on both tanks prohibited." Conversely, my test pilot like the arrangement, saying that for at least the first half tank the engine could be operated on both, keeping the fuel load balanced (well, anyone that has had a Cardinal would not be convinced that would happen). Why do high-wing planes often have a "both" position? Probably because the fuel is joined together at the bottom of the plane, several feet below the tanks. One tank would have to run dry with the other pulling enough vacuum to overcome maybe 4 feet of head pressure - very unlikely. A low wing plane has nowhere to connect the tanks together except essentially even with the bottom of the tanks. When one runs dry air would immediately enter the engine. Just my nickel's worth (inflation, you know) Gary Casey On Sep 11, 2006, at 11:55 PM, AeroElectric-List Digest Server wrote: > George- "... an on/off valve on each > tank introduces problems and complexity..." > > Boy, am I glad you wrote that! I completely missed the part about > independent fuel valves. Kevin, besides all the good points George > makes, > and as someone pointed out a while back on one of these lists, you > will > only find a "BOTH" position on a fuel selector in a high wing > single engine > airplane. The low wing planes have left, right, and off. With a > high wing > plane, you will sometimes see quite an imbalance develop when > drawing fuel > from both tanks simultaneously, even with the head pressure caused > by the > tank location. This effect could be much greater in a low wing > installation. If you had the ability to have both tanks plumbed to > the > engine at the same time, when one tank emptied you could suck air > into the > system. Obviously, this would not be good. I would definitely > recommend > against two fuel valves. > > Sorry for not catching that sooner- > > glen matejcek ________________________________ Message 4 _____________________________________ Time: 07:46:36 AM PST US Subject: RE: AeroElectric-List: Fuel Pump Switch(es) From: "Hinde, Frank George (Corvallis)" Not switching the valve is also one of the advantages of the fuel pumps in the wingroot method. In this case the lines are simply joined together in a tee fitting before going to the on /off valve. In this installation the valve is only turned off in the event of an emergency, never in normal operation. True there is pressurised fuel in the lines in the cockpit...Hopefully in an off field landing one would remember to turn off the pumps. With dead (roller vane FI pumps) pumps the amount of fuel that could trickle through under gravity would be very small, certainly less than the standard arrangement. Incidently my FAA inspector looked very skeptical for a few minutes. Not surpring this guy had built like 5 RV's and this was very different. Thought my "goose was cooked" for a moment but he signed it off once he understood the system. Frank ________________________________ From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Gary Casey Sent: Tuesday, September 12, 2006 7:16 AM Subject: Re: AeroElectric-List: Fuel Pump Switch(es) I might have missed some of the discussion, but the comment below seems to be directed at the tank valving method - specifically whether to use two separate fuel valves or one, with the recommendation to run all the fuel through one valve. I chose to put two valves on mine for the following reasons: 1. A single valve is a single point of failure - what if the handle breaks off or the valve sticks? The most likely time for that to happen is when one port is being closed off before the other opens (apparently most or all fuel selectors go to "off" between right and left positions). If it jams in this position all fuel is shut off. My on-off valves are completely independent and controlled from their own lever and cable. If one jams either open or shut the other is unaffected. 2. The fuel can be shut off at the tank, not in the middle of the cockpit. When both valves are shut off no fuel can enter the cockpit, which would be reassuring in case of an off-airport landing. 3. It reduces the number of fuel fittings and therefore the number of potential leak paths, especially in the cockpit. 4. It allows the backup electric pump to be placed at the lowest point in the fuel system which should provide the best protection against vapor lock. 5. When switching tanks the new tank can be turned on before the old tank is shut off, guaranteeing a continuous flow of fuel. 6. A trivial one: If the plane is landed with an unbalanced fuel load, both valves can be left on, equalizing the fuel load before the next flight. ________________________________ Message 5 _____________________________________ Time: 07:47:11 AM PST US From: "Peter Braswell" Subject: RE: AeroElectric-List: Whelen Strobes Blowing Fuses --> AeroElectric-List message posted by: "Peter Braswell" Bob et. al. - No, this is a brand new install/system and has been exhibiting this behavior from almost day 1. I do have an inline amp meter that I can hook up in an attempt to see what kind of current draw I'm actually getting. I agree with you guys that this and looking for obvious "bad" things (bad switch, bad/faulty connections) is probably the place to start. And yes, you are right Bob, no fancy-smancy equipment in my toolshed as you suggested :-) Thanks! Peter -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Tuesday, September 12, 2006 8:49 AM Subject: Re: AeroElectric-List: Whelen Strobes Blowing Fuses --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" --> At 09:01 PM 9/11/2006 -0400, you wrote: >Gang, >I've got a problem with my Whelen strobe system blowing a 10 amp fuse. > >I'm using a 10 amp mini-blade fuse which is blowing intermittently. >The kit manufacturer as per the instructions, recommends a 10 amp fuse, >but of course they allude to a 10 amp aircraft style reset-able fuse. >I can seem to get the fuse to blow fairly regularly if I turn the >strobes on and off in quick succession. The fuse will blow less >reliably if I turn the strobes on prior to takeoff and just leave them on. > >My questions are these: Would there be any difference in a 10 amp blade >fuse vs. the mechanical breaker style fuse as prescribed by the >manufacturer? And the other question is is there such thing as a >slow-blow m How old is this system? Is this a "new" phenomenon that's popped up after a period of satisfactory operation or has it existed from square-one? Have you placed an ammeter in series with the supply line to measure the system's current draw? You need an analog meter to get some notion of minimum and maximum current between firings. Which strobe system is it? >ini blade style fuse and could this possibly make a difference? And >finally perhaps there is something more insidious at work here? Fuses are faster to respond than most breakers. It could be that your strobes are drawing an average well below the 10A rating of the fuse but hit it repeatedly with levels that exceed 10A and degrade the fuse over a period of time. The real definitive measurement would be to put a data acquisition system on it and watch it for a period of time and the compare that data with a system that performs as expected. Unfortunately, most folks in your position don't have access to such equipment and you're stuck with hip-shots hopefully filtered through some sense of the physics. Bob . . . --------------------------------------------------------- < What is so wonderful about scientific truth...is that > < the authority which determines whether there can be > < debate or not does not reside in some fraternity of > < scientists; nor is it divine. The authority rests > < with experiment. > < --Lawrence M. Krauss > --------------------------------------------------------- ________________________________ Message 6 _____________________________________ Time: 08:50:45 AM PST US Subject: RE: AeroElectric-List: Whelen Strobes Blowing Fuses From: "Matt Prather" --> AeroElectric-List message posted by: "Matt Prather" Is the mini blade fuse smaller than the regular ATC fuse (for which b and c sells holders)? Many amp meters are limited to 10A. If the trouble you are having is blowing a 10A fuse, likely the circuit is drawing more than 10A. Be a little careful here with the meter, though it's also likely fuse protected. As Bob has mentioned in the past, an analog meter often has faster response time than many Digital MultiMeters (DMM). The quicker response time can help in observing transient behavior in a circuit. It may be quite a bit ea$ier to get an analog ammeter than it would be to get a more sophisticated data acquistion system. Dumb question: Is there anything else wired on the same 10A fuse circuit (even though maybe it's turned off)? If a device has much input capacitance (power supply caps), turning the device on can cause a significant above-steady-state current draw - to charge the caps. Power cycling the device repeatedly can generate higher average current. Regards, Matt- > --> AeroElectric-List message posted by: "Peter Braswell" > > > > Bob et. al. - > No, this is a brand new install/system and has been exhibiting this > behavior > from almost day 1. > > I do have an inline amp meter that I can hook up in an attempt to see what > kind of current draw I'm actually getting. I agree with you guys that > this > and looking for obvious "bad" things (bad switch, bad/faulty connections) > is > probably the place to start. > > And yes, you are right Bob, no fancy-smancy equipment in my toolshed as > you > suggested :-) > > Thanks! > Peter > > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert > L. > Nuckolls, III > Sent: Tuesday, September 12, 2006 8:49 AM > To: aeroelectric-list@matronics.com > Subject: Re: AeroElectric-List: Whelen Strobes Blowing Fuses > > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > --> > > At 09:01 PM 9/11/2006 -0400, you wrote: > >>Gang, >>I've got a problem with my Whelen strobe system blowing a 10 amp fuse. >> >>I'm using a 10 amp mini-blade fuse which is blowing intermittently. >>The kit manufacturer as per the instructions, recommends a 10 amp fuse, >>but of course they allude to a 10 amp aircraft style reset-able fuse. >>I can seem to get the fuse to blow fairly regularly if I turn the >>strobes on and off in quick succession. The fuse will blow less >>reliably if I turn the strobes on prior to takeoff and just leave them >> on. >> >>My questions are these: Would there be any difference in a 10 amp blade >>fuse vs. the mechanical breaker style fuse as prescribed by the >>manufacturer? And the other question is is there such thing as a >>slow-blow m > > How old is this system? Is this a "new" phenomenon that's > popped up after a period of satisfactory operation or has > it existed from square-one? Have you placed an ammeter in > series with the supply line to measure the system's current > draw? You need an analog meter to get some notion of minimum > and maximum current between firings. Which strobe system is it? > >>ini blade style fuse and could this possibly make a difference? And >>finally perhaps there is something more insidious at work here? > > Fuses are faster to respond than most breakers. It could > be that your strobes are drawing an average well below > the 10A rating of the fuse but hit it repeatedly with > levels that exceed 10A and degrade the fuse over a period > of time. > > The real definitive measurement would be to put a data acquisition > system on it and watch it for a period of time and the compare > that data with a system that performs as expected. Unfortunately, > most folks in your position don't have access to such equipment > and you're stuck with hip-shots hopefully filtered through some sense > of the physics. > > Bob . . . > > > --------------------------------------------------------- > < What is so wonderful about scientific truth...is that > > < the authority which determines whether there can be > > < debate or not does not reside in some fraternity of > > < scientists; nor is it divine. The authority rests > > < with experiment. > > < --Lawrence M. Krauss > > --------------------------------------------------------- > > ________________________________ Message 7 _____________________________________ Time: 09:05:54 AM PST US From: "Peter Braswell" Subject: RE: AeroElectric-List: Whelen Strobes Blowing Fuses --> AeroElectric-List message posted by: "Peter Braswell" Matt, Thank you very much for the input. I probably need to offer a amendment/correction to my earlier post, prompted by one of your questions. I perhaps may have mis-named what I'm using. I AM using a 10a ATC fuse. I purchased an assorted tray of them from Stein Air. Sorry for the confusion. Also, I do not have anything else on that circuit. I tried very hard (and succeeded) to have one device/one fuse. Peter -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Matt Prather Sent: Tuesday, September 12, 2006 11:49 AM Subject: RE: AeroElectric-List: Whelen Strobes Blowing Fuses --> AeroElectric-List message posted by: "Matt Prather" --> Is the mini blade fuse smaller than the regular ATC fuse (for which b and c sells holders)? Many amp meters are limited to 10A. If the trouble you are having is blowing a 10A fuse, likely the circuit is drawing more than 10A. Be a little careful here with the meter, though it's also likely fuse protected. As Bob has mentioned in the past, an analog meter often has faster response time than many Digital MultiMeters (DMM). The quicker response time can help in observing transient behavior in a circuit. It may be quite a bit ea$ier to get an analog ammeter than it would be to get a more sophisticated data acquistion system. Dumb question: Is there anything else wired on the same 10A fuse circuit (even though maybe it's turned off)? If a device has much input capacitance (power supply caps), turning the device on can cause a significant above-steady-state current draw - to charge the caps. Power cycling the device repeatedly can generate higher average current. Regards, Matt- > --> AeroElectric-List message posted by: "Peter Braswell" > > > > Bob et. al. - > No, this is a brand new install/system and has been exhibiting this > behavior from almost day 1. > > I do have an inline amp meter that I can hook up in an attempt to see > what kind of current draw I'm actually getting. I agree with you guys > that this and looking for obvious "bad" things (bad switch, bad/faulty > connections) is probably the place to start. > > And yes, you are right Bob, no fancy-smancy equipment in my toolshed > as you suggested :-) > > Thanks! > Peter > > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of > Robert L. > Nuckolls, III > Sent: Tuesday, September 12, 2006 8:49 AM > To: aeroelectric-list@matronics.com > Subject: Re: AeroElectric-List: Whelen Strobes Blowing Fuses > > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > --> > > At 09:01 PM 9/11/2006 -0400, you wrote: > >>Gang, >>I've got a problem with my Whelen strobe system blowing a 10 amp fuse. >> >>I'm using a 10 amp mini-blade fuse which is blowing intermittently. >>The kit manufacturer as per the instructions, recommends a 10 amp >>fuse, but of course they allude to a 10 amp aircraft style reset-able fuse. >>I can seem to get the fuse to blow fairly regularly if I turn the >>strobes on and off in quick succession. The fuse will blow less >>reliably if I turn the strobes on prior to takeoff and just leave them >>on. >> >>My questions are these: Would there be any difference in a 10 amp >>blade fuse vs. the mechanical breaker style fuse as prescribed by the >>manufacturer? And the other question is is there such thing as a >>slow-blow m > > How old is this system? Is this a "new" phenomenon that's > popped up after a period of satisfactory operation or has > it existed from square-one? Have you placed an ammeter in > series with the supply line to measure the system's current > draw? You need an analog meter to get some notion of minimum > and maximum current between firings. Which strobe system is it? > >>ini blade style fuse and could this possibly make a difference? And >>finally perhaps there is something more insidious at work here? > > Fuses are faster to respond than most breakers. It could > be that your strobes are drawing an average well below > the 10A rating of the fuse but hit it repeatedly with > levels that exceed 10A and degrade the fuse over a period > of time. > > The real definitive measurement would be to put a data acquisition > system on it and watch it for a period of time and the compare > that data with a system that performs as expected. Unfortunately, > most folks in your position don't have access to such equipment > and you're stuck with hip-shots hopefully filtered through some sense > of the physics. > > Bob . . . > > > --------------------------------------------------------- > < What is so wonderful about scientific truth...is that > > < the authority which determines whether there can be > > < debate or not does not reside in some fraternity of > > < scientists; nor is it divine. The authority rests > > < with experiment. > > < --Lawrence M. Krauss > > --------------------------------------------------------- > > ________________________________ Message 8 _____________________________________ Time: 09:48:34 AM PST US From: "John Burnaby" Subject: Re: AeroElectric-List: Fuel Pump Switch(es)Fuel Pump Switch(es)Fuel Pump Switch(es) My $.02. Electrically dependent planes with two pumps need a dedicated switch for each pump drawing from independent power sources. FWIW, I am using an EFI on my 6cyl Franklin in a Glasair TD and have spent a lot of hours thinking about my fuel system. As fuel starvation seems to be the most common cause of engine stoppage, and that my 58 year old ADD noggin sometimes trys to kill me, I wanted a system that was as idiot proof as possible. That meant not having to remember to switch tanks, that all fuel in the system goes to the intake of the pumps no matter what I do. All I have to remember is to turn on the pump(s) when I start the engine. I have a fool proof reminder to do that, when the engine won't start. Fuel from my split tanks flows through one way umbrella valves to a common sump,on the bottom of the wing and at the low point of the fuel system. A header tank is also plumbed to the sump. All recirculated fuel goes back to the header with an internal overflow well that will dump the overflow back to the mains. Both pumps, (separate switches, to two batteries), pointed aft, draw from the common sump. There is no R-L selector valve, no shut off valve, as the Bosch aerotor pumps, each with a built in check valve, do not flow fuel without power and the fuel filter on the FW is higher than the sump . If I don't want fuel to flow to the engine, I turn off a switch. There is an on-off valve for the header tank so that I can allow the header to be refilled from recirculated fuel to use for landings and TO's (more head on the pump intakes), however if I forget to turn this on, and the tank fills, it will overflow back to the mains. As long as their is fuel on board, it will flow to the pump intakes, mental incapacitation of the pilot notwithstanding. ________________________________ Message 9 _____________________________________ Time: 12:40:27 PM PST US From: "james wickert" Subject: RE: AeroElectric-List: Whelen Strobes Blowing Fuses --> AeroElectric-List message posted by: "james wickert" Food for thought a full strobe system can draw from 7 A for the Whelen A413A HDA-CF at 14 Volts to as low as 1.7A with the A409ATS CF at 14 volts. If you have a 7A operating unit when you turn it on it could I believe when loading up the capacitors to fire the 4kv trigger coil and provide the 250v anode to cathode current....I am not sure if it would surge the load to over 10 Amps? Jim Wickert Vision CorvAir #159 > [Original Message] > From: Peter Braswell > To: > Date: 9/12/2006 11:17:56 AM > Subject: RE: AeroElectric-List: Whelen Strobes Blowing Fuses > > --> AeroElectric-List message posted by: "Peter Braswell" > > > Matt, > Thank you very much for the input. > > I probably need to offer a amendment/correction to my earlier post, prompted > by one of your questions. I perhaps may have mis-named what I'm using. I > AM using a 10a ATC fuse. I purchased an assorted tray of them from Stein > Air. Sorry for the confusion. > > Also, I do not have anything else on that circuit. I tried very hard (and > succeeded) to have one device/one fuse. > > Peter > > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Matt > Prather > Sent: Tuesday, September 12, 2006 11:49 AM > To: aeroelectric-list@matronics.com > Subject: RE: AeroElectric-List: Whelen Strobes Blowing Fuses > > --> AeroElectric-List message posted by: "Matt Prather" > --> > > Is the mini blade fuse smaller than the regular ATC fuse (for which b and c > sells holders)? > > Many amp meters are limited to 10A. If the trouble you are having is > blowing a 10A fuse, likely the circuit is drawing more than 10A. Be a > little careful here with the meter, though it's also likely fuse protected. > > As Bob has mentioned in the past, an analog meter often has faster response > time than many Digital MultiMeters (DMM). The quicker response time can > help in observing transient behavior in a circuit. It may be quite a bit > ea$ier to get an analog ammeter than it would be to get a more sophisticated > data acquistion system. > > Dumb question: Is there anything else wired on the same 10A fuse circuit > (even though maybe it's turned off)? > > If a device has much input capacitance (power supply caps), turning the > device on can cause a significant above-steady-state current draw - to > charge the caps. Power cycling the device repeatedly can generate higher > average current. > > > Regards, > > Matt- > > > --> AeroElectric-List message posted by: "Peter Braswell" > > > > > > > > Bob et. al. - > > No, this is a brand new install/system and has been exhibiting this > > behavior from almost day 1. > > > > I do have an inline amp meter that I can hook up in an attempt to see > > what kind of current draw I'm actually getting. I agree with you guys > > that this and looking for obvious "bad" things (bad switch, bad/faulty > > connections) is probably the place to start. > > > > And yes, you are right Bob, no fancy-smancy equipment in my toolshed > > as you suggested :-) > > > > Thanks! > > Peter > > > > -----Original Message----- > > From: owner-aeroelectric-list-server@matronics.com > > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of > > Robert L. > > Nuckolls, III > > Sent: Tuesday, September 12, 2006 8:49 AM > > To: aeroelectric-list@matronics.com > > Subject: Re: AeroElectric-List: Whelen Strobes Blowing Fuses > > > > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > --> > > > > At 09:01 PM 9/11/2006 -0400, you wrote: > > > >>Gang, > >>I've got a problem with my Whelen strobe system blowing a 10 amp fuse. > >> > >>I'm using a 10 amp mini-blade fuse which is blowing intermittently. > >>The kit manufacturer as per the instructions, recommends a 10 amp > >>fuse, but of course they allude to a 10 amp aircraft style reset-able > fuse. > >>I can seem to get the fuse to blow fairly regularly if I turn the > >>strobes on and off in quick succession. The fuse will blow less > >>reliably if I turn the strobes on prior to takeoff and just leave them > >>on. > >> > >>My questions are these: Would there be any difference in a 10 amp > >>blade fuse vs. the mechanical breaker style fuse as prescribed by the > >>manufacturer? And the other question is is there such thing as a > >>slow-blow m > > > > How old is this system? Is this a "new" phenomenon that's > > popped up after a period of satisfactory operation or has > > it existed from square-one? Have you placed an ammeter in > > series with the supply line to measure the system's current > > draw? You need an analog meter to get some notion of minimum > > and maximum current between firings. Which strobe system is it? > > > >>ini blade style fuse and could this possibly make a difference? And > >>finally perhaps there is something more insidious at work here? > > > > Fuses are faster to respond than most breakers. It could > > be that your strobes are drawing an average well below > > the 10A rating of the fuse but hit it repeatedly with > > levels that exceed 10A and degrade the fuse over a period > > of time. > > > > The real definitive measurement would be to put a data acquisition > > system on it and watch it for a period of time and the compare > > that data with a system that performs as expected. Unfortunately, > > most folks in your position don't have access to such equipment > > and you're stuck with hip-shots hopefully filtered through some sense > > of the physics. > > > > Bob . . . > > > > > > --------------------------------------------------------- > > < What is so wonderful about scientific truth...is that > > > < the authority which determines whether there can be > > > < debate or not does not reside in some fraternity of > > > < scientists; nor is it divine. The authority rests > > > < with experiment. > > > < --Lawrence M. Krauss > > > --------------------------------------------------------- > > > > > > > > > > > > > > > > > > > > > > > > ________________________________ Message 10 ____________________________________ Time: 12:59:02 PM PST US From: Speedy11@aol.com Subject: AeroElectric-List: Re: AeroElectric-List Digest: 26 Msgs - 09/10/06 In a forum such as this, you really need to be sure of your answer before you post one. That's for damn sure! Stan Sutterfield Do not archive ________________________________ Message 11 ____________________________________ Time: 06:18:14 PM PST US From: Bob White Subject: Re: AeroElectric-List: Alternator Problem - Not in plane --> AeroElectric-List message posted by: Bob White On Sun, 10 Sep 2006 07:34:43 EDT FLYaDIVE@aol.com wrote: > --> AeroElectric-List message posted by: FLYaDIVE@aol.com > > In a message dated 9/9/06 10:54:08 AM Eastern Daylight Time, > ceengland@bellsouth.net writes: > > > If they came off small cars, they might not be rated for that much > > current & unable to maintain voltage if you demand excess current. > > > > Another thought: are they internally or externally regulated? If > > external & you're using a regulator built into the test set, are you > > sure the test set regulator is set correctly and are you sure the test > > set voltmeter is accurate? Getting the same volt reading for all using > > one test set & a different, same volt reading for all on another test > > set seems to point at the test sets. > ==================================== > Charlie: > > The rated amperage of the alternator is 90 Amps. > Normal draw is about 15 Amps. > It is internally regulated. > The test benches are at automotive parts stores and rebuilding shops. > At both locations, on all 4 alternators the output was 10.5 V. > > This is a crazy problem. It is not a simple problem. I know there is > someone out there with the knowledge and past experience of this situation. If is > was simple I would have solved it months ago. NO ONE has been able to identify > the problem. Not even Hyundai or Bosch. And it is their alternator's! > > > Barry > "Chop'd Liver" > Hi Barry, I've been thinking about your alternator problem. I wonder if it could be as simple as having a bit of series resistance between the alternator and the voltmeter. At 90 amps, you only need 0.04 to 0.05 ohms to see that kind of voltage drop. Test equipment I've seen at parts stores have a big clips to connect to the alternator and I could easily imagine having that much resistance in the connections. Particularly with 90 amps running through them. The fact that the voltage varied from 10.5 V to 12.2 V with a different tester is an indication of that kind of problem. (Or the voltmeters aren't very accurate.) If possible, try the test with a voltmeter connected directly to the B lead and alternator case so that none of the test current is flowing in the leads to the voltmeter. Bob W. -- http://www.bob-white.com N93BD - Rotary Powered BD-4 (first engine start 1/7/06) Custom Cables for your rotary installation - http://www.roblinphoto.com/shop/ ________________________________ Message 12 ____________________________________ Time: 06:18:15 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Whelen Strobes Blowing Fuses --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 12:03 PM 9/12/2006 -0400, you wrote: >--> AeroElectric-List message posted by: "Peter Braswell" > > > >Matt, >Thank you very much for the input. > >I probably need to offer a amendment/correction to my earlier post, prompted >by one of your questions. I perhaps may have mis-named what I'm using. I >AM using a 10a ATC fuse. I purchased an assorted tray of them from Stein >Air. Sorry for the confusion. > >Also, I do not have anything else on that circuit. I tried very hard (and >succeeded) to have one device/one fuse. > >Peter Okay. Just for grins, put a 15A fuse in and see what happens. 15A is not so much greater as to put the wire in danger. I presume the strobe is running normally when the fuse is not blown. The 15A fuse experiment will help us put a crude bound on the incoming current and at least show that it's not a transient hard fault which will blow the 15A fuse too Bob . . . ________________________________ Message 13 ____________________________________ Time: 06:18:15 PM PST US From: Kevin Horton Subject: Re: AeroElectric-List: Fuel Pump Switch(es) --> AeroElectric-List message posted by: Kevin Horton On 12 Sep 2006, at 10:15, Gary Casey wrote: > I might have missed some of the discussion, but the comment below > seems to be directed at the tank valving method - specifically > whether to use two separate fuel valves or one, with the > recommendation to run all the fuel through one valve. I chose to > put two valves on mine for the following reasons: > > 1. A single valve is a single point of failure - what if the > handle breaks off or the valve sticks? The most likely time for > that to happen is when one port is being closed off before the > other opens (apparently most or all fuel selectors go to "off" > between right and left positions). If it jams in this position all > fuel is shut off. My on-off valves are completely independent and > controlled from their own lever and cable. If one jams either open > or shut the other is unaffected. > 2. The fuel can be shut off at the tank, not in the middle of the > cockpit. When both valves are shut off no fuel can enter the > cockpit, which would be reassuring in case of an off-airport landing. > 3. It reduces the number of fuel fittings and therefore the number > of potential leak paths, especially in the cockpit. > 4. It allows the backup electric pump to be placed at the lowest > point in the fuel system which should provide the best protection > against vapor lock. > 5. When switching tanks the new tank can be turned on before the > old tank is shut off, guaranteeing a continuous flow of fuel. > 6. A trivial one: If the plane is landed with an unbalanced fuel > load, both valves can be left on, equalizing the fuel load before > the next flight. > > The disadvantage is that both valves could be inadvertently turned > on, which on a low-wing plane means that if one tank is run dry in > that condition the engine could draw air. In that case one fuel > gage would read empty and changing the fuel valve positions > (shutting off the empty tank) would correct the condition. > Interestingly, my DAR was skeptical about the arrangement, but was > satisfied by the placement of a placard "continuous operation on > both tanks prohibited." Conversely, my test pilot like the > arrangement, saying that for at least the first half tank the > engine could be operated on both, keeping the fuel load balanced > (well, anyone that has had a Cardinal would not be convinced that > would happen). Why do high-wing planes often have a "both" > position? Probably because the fuel is joined together at the > bottom of the plane, several feet below the tanks. One tank would > have to run dry with the other pulling enough vacuum to overcome > maybe 4 feet of head pressure - very unlikely. A low wing plane > has nowhere to connect the tanks together except essentially even > with the bottom of the tanks. When one runs dry air would > immediately enter the engine. You are worried about fuel valve handles breaking. With your design, what happens if you have run one tank down low, want to switch to the other tank, and the valve handle on the tank that is feeding breaks so you can't close that valve? Won't the engine quit once that tank is empty and the engine starts sucking air? How is this better than a valve handle failure with the normal design? Kevin Horton RV-8 (finishing kit) Ottawa, Canada http://www.kilohotel.com/rv8 ________________________________ Message 14 ____________________________________ Time: 06:29:50 PM PST US From: "Peter Braswell" Subject: RE: AeroElectric-List: Whelen Strobes Blowing Fuses --> AeroElectric-List message posted by: "Peter Braswell" Bob, Easy enough to do! I'll give it a whirl and see what happens. And to answer your question, yes the strobe work fine when it is working. Thanks! Peter -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Tuesday, September 12, 2006 9:11 PM Subject: RE: AeroElectric-List: Whelen Strobes Blowing Fuses --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" --> At 12:03 PM 9/12/2006 -0400, you wrote: >--> AeroElectric-List message posted by: "Peter Braswell" > > > >Matt, >Thank you very much for the input. > >I probably need to offer a amendment/correction to my earlier post, >prompted by one of your questions. I perhaps may have mis-named what >I'm using. I AM using a 10a ATC fuse. I purchased an assorted tray of >them from Stein Air. Sorry for the confusion. > >Also, I do not have anything else on that circuit. I tried very hard >(and >succeeded) to have one device/one fuse. > >Peter Okay. Just for grins, put a 15A fuse in and see what happens. 15A is not so much greater as to put the wire in danger. I presume the strobe is running normally when the fuse is not blown. The 15A fuse experiment will help us put a crude bound on the incoming current and at least show that it's not a transient hard fault which will blow the 15A fuse too Bob . . . ________________________________ Message 15 ____________________________________ Time: 07:02:25 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Whelen Strobes Blowing Fuses --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:49 AM 9/12/2006 -0600, you wrote: >--> AeroElectric-List message posted by: "Matt Prather" > >Is the mini blade fuse smaller than the regular ATC fuse (for which b and >c sells holders)? Interesting question. If he WAS using the ATM "mini" fuses, would we expect it to be twitchy compared to it's larger brother. I uploaded the spec sheets to: http://www.aeroelectric.com/Mfgr_Data/Fuses_and_Current_Limiters/Bussman/ATC_Specs.pdf and http://www.aeroelectric.com/Mfgr_Data/Fuses_and_Current_Limiters/Bussman/ATC_Specs.pdf I note that the "little guys" spec the same headroom (ATM-3 ATC-3 fuses both go asymtotic at 4A). At 10A, the ATM-3 average blow is about 140 mS and the ATC-3 is 80 mS. I don't know if you were thinking the same thing I was but in any case, it's interesting to note that the smaller fuse has a bit more thermo-dynamic mass than big brother. Who wuda thunk it? >As Bob has mentioned in the past, an analog meter often has faster >response time than many Digital MultiMeters (DMM). The quicker response >time can help in observing transient behavior in a circuit. It may be >quite a bit ea$ier to get an analog ammeter than it would be to get a more >sophisticated data acquistion system. One of the reasons I keep analog meters around is to watch trends/dynamics of the parameter being observed. A digital meter is difficult to get a sense of min/max, duty cycle (stays high longer than low) and frequency. Digitals may be giving be perfectly accurate data for each time they take a reading (typically 1 to 4 times per second) but one cannot deduce the behaviors cited from what appears to be a dancing set of random numbers. Many digital meters have a bar graph built in under the digits but it's hard to beat the black pointer waving across a white scale to get a sense of "the beat". Bob . . .