---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 07/11/12: 16 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:56 AM - Re: grounding procedures (Jay Hyde) 2. 01:01 AM - Re: grounding procedures (Jay Hyde) 3. 01:32 AM - Re: grounding procedures (rayj) 4. 01:43 AM - This one is REALLY from me! - celui-ci est vraiment de moi! (Ian Wilson) 5. 04:38 AM - Over-voltage Circuit Trips (Jack Haviland) 6. 06:04 AM - Re: Ground jumping on Z-14 (Chris Barber) 7. 06:46 AM - Re: OT: batteries in series on maintainer (Robert L. Nuckolls, III) 8. 09:13 AM - Re: grounding procedures (Robert L. Nuckolls, III) 9. 10:52 AM - Re: grounding procedures (rayj) 10. 03:23 PM - Re: OT: batteries in series on maintainer (rayj) 11. 03:31 PM - Re: Z12 Alternator Amps (RV7ASask) 12. 04:39 PM - Re: Re: Z12 Alternator Amps (Bob McCallum) 13. 05:09 PM - Re: Re: Z12 Alternator Amps (Robert L. Nuckolls, III) 14. 05:27 PM - Re: grounding procedures (bob noffs) 15. 05:44 PM - Re: grounding procedures (Robert L. Nuckolls, III) 16. 06:47 PM - Re: grounding procedures (bob noffs) ________________________________ Message 1 _____________________________________ Time: 12:56:40 AM PST US From: "Jay Hyde" Subject: RE: AeroElectric-List: grounding procedures Hi there Bob, The point of grounding is to ensure that all items in the fuelling process are at the same potential; no potential difference then no spark between items; no spark, no BOOM! (sometimes started off by a small and seemingly insignificant announcement like, 'oh, damn!') You get a potential difference between items because of static build up, perhaps a bit of capacitance, and from the flow of the fuel itself (working similarly to you rubbing a jersey against your car in dry air- static build up). Connect a thin wire (even 22AWG would be fine) from the negative of your external pump battery and run it along the fuel tubing to the metal filter- and also back to your plastic can. Connect it electrically to the filter and continue along to the end of the tube where it goes into the tank. Put a crocodile clip on the end and connect that to the tank inlet- also put a croc clip at the plastic can end and clip it to the can. You can also run a lead to the exhaust but essentially the only place that you are concerned about is where the fuel could ignite- right at the filler. By running that wire all along the fuel line, from source to delivery point, each item is held at the same potential; no potential difference, no spark. Yes, I know that the refuelling can is plastic, but plastic can still build up a static charge. As an additional precaution you could also connect the battery negative to a metal plate that it lies on top of, but, that can be quite meaningless in terms of earthing/ grounding the system, depending on what surface this is all sitting on. Better to bring the whole system to voltage equality by holding the metal filter when you approach the aircraft and then touch the wing with your palm. Any potential difference will be balanced and you can now connect the delivery side to the tank inlet comfortably. Jay From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of bob noffs Sent: 10 July 2012 06:38 PM Subject: AeroElectric-List: grounding procedures hi all, lately i have been filling my plane out of 5 gal. plastic cans and i am finding it not too time consuming. the biggest reason is higher octane mogas than i can get at the airport. anyway.............i need some advice on grounding.i have a 12 volt pump mounted and it is powered by a battery 20 feet away. i have a handheld switch . i set the plastic can on the table and fuel is transferred thru vinyl tubing. at the airplane end is a metal filter. pumps a gallon a minute. i plan to set up a ground to the exhaust pipe [all tanks are grounded to the engine] but i do not know how to ground the pump or hoses. any advice would be appreciated. bob noffs ________________________________ Message 2 _____________________________________ Time: 01:01:45 AM PST US From: "Jay Hyde" Subject: RE: AeroElectric-List: grounding procedures That'll work. Jay From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of bob noffs Sent: 10 July 2012 10:19 PM Subject: Re: AeroElectric-List: grounding procedures i am thinking of pushing a copper wire thru the vinyl hose from each end [an end in the can and an end in the aircraft] and when i get to the metal pump i am thinking i can clamp the wire between the vinyl tube wall and the metal barb on the pump. the pump will then be grounded. also ground the plane. how bout that? bob noffs On Tue, Jul 10, 2012 at 2:20 PM, David Lloyd wrote: This is a very worth while thread.... as some time or another, fueling with portable containers can bite you... Some suggestions to add to others replying..... * be especially aware of the static spark problem on hotter, drier days.. * the flowing fuel itself generates static voltage, again, dry days are worse. * some insert a type of copper ground wire inside the fueling line itself so that it is in contact with the fuel from end to end; plastic container to funnel and aircraft. * plastic containers as mentioned before are the worst for fueling when they are used directly on the wing pouring. If on the end of an extended fuel hose via a pump, that is different but, still a problem as the vinyl hose could easily build up a static charge. That is where the copper wire running the whole length inside the hose would help drain off any building charge. * again, as mentioned earlier it is important to figure a method to ground the fuel contain, hoses, etc. to the tank being filled. If done properly, no static of any consequence should build to the point of a discharge. Hopefully, others will add to and correct this list. I also have a personal example of what this kind of accident can do. A local gal, who was a 1st class ultralights pilot and instructor, was filling her wing tank via a plastic container on a warm, dry day in Oregon. A spark jumped, fire ensued instantly and she too accidently got fuel splashed on her as she jumped down. Ultralights was a total loss and she spent years trying to get her body damage corrected with surgery. Dave ----- Original Message ----- From: "Dave Saylor" Sent: Tuesday, July 10, 2012 10:54 AM Subject: Re: AeroElectric-List: grounding procedures My understanding is that the greatest danger comes from a spark jumping between the container and the filler neck. To prevent that, I always very consciously keep the spout in contact with the filler neck. When I'm finished filling, I methodically drag the spout away from the opening before breaking contact. That way, if a spark jumps the gap, it doesn't happen near the filler opening. The worst accident I've heard of (I met the victim) illustrates some valuable lessons. He was pouring fuel from a bucket through a funnel into a wing. He got the spark/flash, and it wouldn't have been as horrible if he hadn't instinctively jumped back and spilled the bucket all over himself. He's lucky to be alive but he'll never be the same. So another point is to use a closed container with a smallish neck and opening. That way the flash doesn't ignite the entire volume, and it doesn't spill as fast if it's dropped. I've been told that grounding a plastic container is very difficult. I'm curious to hear what others have to say. Dave Saylor 831-750-0284 CL On Tue, Jul 10, 2012 at 9:37 AM, bob noffs wrote: hi all, lately i have been filling my plane out of 5 gal. plastic cans and i am finding it not too time consuming. the biggest reason is higher octane mogas than i can get at the airport. anyway.............i need some advice on grounding.i have a 12 volt pump mounted and it is powered by a battery 20 feet away. i have a handheld switch . i set the plastic can on the table and fuel is transferred thru vinyl tubing. at the airplane end is a metal filter. pumps a gallon a minute. i plan to set up a ground to the exhaust pipe [all tanks are grounded to the engine] but i do not know how to ground the pump or hoses. any advice would be appreciated. bob noffs =================================== -List" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List =================================== http://forums.matronics.com =================================== le, List Admin. ="_blank">http://www.matronics.com/contribution =================================== ________________________________ Message 3 _____________________________________ Time: 01:32:46 AM PST US From: rayj Subject: Re: AeroElectric-List: grounding procedures Bob, Another thing to consider is what happens if/when the pump fails in some way. Is it possible for the electrons to find a path that would cause a problem? I don't have an answer, but it seems like another possible way for bad things to happen. Raymond Julian Kettle River, MN. "And you know that I could have me a million more friends, and all I'd have to lose is my point of view." - John Prine On 07/10/2012 03:19 PM, bob noffs wrote: > i am thinking of pushing a copper wire thru the vinyl hose from each end > [an end in the can and an end in the aircraft] and when i get to the > metal pump i am thinking i can clamp the wire between the vinyl tube > wall and the metal barb on the pump. the pump will then be grounded. > also ground the plane. how bout that? > bob noffs > > On Tue, Jul 10, 2012 at 2:20 PM, David Lloyd > wrote: > > > > > This is a very worth while thread.... as some time or another, > fueling with portable containers can bite you... > Some suggestions to add to others replying..... > > * be especially aware of the static spark problem on hotter, drier > days.. > * the flowing fuel itself generates static voltage, again, dry days > are worse. > * some insert a type of copper ground wire inside the fueling line > itself so that it is in contact with the fuel from end to end; > plastic container to funnel and aircraft. > * plastic containers as mentioned before are the worst for fueling > when they are used directly on the wing pouring. If on the end of > an extended fuel hose via a pump, that is different but, still a > problem as the vinyl hose could easily build up a static charge. > That is where the copper wire running the whole length inside the > hose would help drain off any building charge. > * again, as mentioned earlier it is important to figure a method to > ground the fuel contain, hoses, etc. to the tank being filled. If > done properly, no static of any consequence should build to the > point of a discharge. > > Hopefully, others will add to and correct this list. > > I also have a personal example of what this kind of accident can do. > A local gal, who was a 1st class ultralights pilot and instructor, > was filling her wing tank via a plastic container on a warm, dry day > in Oregon. A spark jumped, fire ensued instantly and she too > accidently got fuel splashed on her as she jumped down. Ultralights > was a total loss and she spent years trying to get her body damage > corrected with surgery. Dave > > > ----- Original Message ----- From: "Dave Saylor" > > > To: > > Sent: Tuesday, July 10, 2012 10:54 AM > Subject: Re: AeroElectric-List: grounding procedures > > > > > > My understanding is that the greatest danger comes from a spark > jumping between the container and the filler neck. > > To prevent that, I always very consciously keep the spout in contact > with the filler neck. When I'm finished filling, I methodically > drag > the spout away from the opening before breaking contact. That > way, if > a spark jumps the gap, it doesn't happen near the filler opening. > > The worst accident I've heard of (I met the victim) illustrates some > valuable lessons. He was pouring fuel from a bucket through a > funnel > into a wing. He got the spark/flash, and it wouldn't have been as > horrible if he hadn't instinctively jumped back and spilled the > bucket > all over himself. He's lucky to be alive but he'll never be the > same. > So another point is to use a closed container with a smallish neck > and opening. That way the flash doesn't ignite the entire > volume, and > it doesn't spill as fast if it's dropped. > > I've been told that grounding a plastic container is very difficult. > I'm curious to hear what others have to say. > > Dave Saylor > 831-750-0284 CL > > > On Tue, Jul 10, 2012 at 9:37 AM, bob noffs > wrote: > > hi all, > lately i have been filling my plane out of 5 gal. plastic > cans and i am > finding it not too time consuming. the biggest reason is > higher octane mogas > than i can get at the airport. > anyway.............i need some advice on grounding.i have > a 12 volt pump > mounted and it is powered by a battery 20 feet away. i have > a handheld > switch . i set the plastic can on the table and fuel is > transferred thru > vinyl tubing. at the airplane end is a metal filter. pumps a > gallon a > minute. i plan to set up a ground to the exhaust pipe [all > tanks are > grounded to the engine] but i do not know how to ground > the pump or hoses. > any advice would be appreciated. > bob noffs > > > ====__==============================__= > -List" > target="_blank">http://www.matronics.com/__Navigator?AeroElectric-List > ====__==============================__= > http://forums.matronics.com > ====__==============================__= > le, List Admin. > ="_blank">http://www.matronics.com/__contribution > ====__==============================__= > > > * > > > * > ________________________________ Message 4 _____________________________________ Time: 01:43:27 AM PST US From: Ian Wilson Subject: AeroElectric-List: This one is REALLY from me! - celui-ci est vraiment de moi! Apologies to everyone for the 2 emails that you have received from my accou nt over the last 24 hours. I made the mistake of using a friends PC to acc ess my email when we were away - lesson learnt! For those of you that have clicked on the link in the emails=2C can I sugge st that you change your email password as soon as possible to avoid this vi rus spreading. Ian et en Francias...... Toutes mes excuses =E0 tous pour les 2 e-mails que vous avez re=E7us de mon compte au cours des derni=E8res 24 heures. J'ai fait l'erreur d'utiliser u n PC des amis =E0 acc=E9der =E0 mon courriel lorsque nous =E9tions en vacan ces - le=E7on apprise! Pour ceux d'entre vous qui ont cliqu=E9 sur le lien dans les e-mails=2C pu is-je sugg=E9rer que vous changez votre mot de passe e-mail d=E8s que possi ble pour =E9viter cette propagation du virus. Ian ________________________________ Message 5 _____________________________________ Time: 04:38:51 AM PST US From: Jack Haviland Subject: AeroElectric-List: Over-voltage Circuit Trips Bob N. et al, Since my RV first flew about a year ago the over-voltage circuit has frequently tripped shortly after take off. Resetting the 5 amp pull-able circuit breaker once or twice generally prevents a re-occurence for the remainder of the flight but I need to determine the root cause and correct it. The plane is wired in general conformance with the Z-11 architecture using Van's 30 amp externally regulated alternator, their potted Transpo regulator, Bob's potted over-voltage detection device and a PC-680 battery. Prior to start the main bus voltage is usually around 12.5-12.8 volts measured with a meter plugged into a convenience outlet. After start, the voltage reported by the Grand Rapids EIS (on the endurance bus) is around 13.2-13.6 volts. I've never been able to detect a high voltage reading either on the plug-in meter or on the EIS before the over-voltage breaker trips. The breaker was purchased from a used parts supplier at Oshkosh and is a "prime suspect" but trouble shooting suggestions would be appreciated. Jack H. ________________________________ Message 6 _____________________________________ Time: 06:04:32 AM PST US From: Chris Barber Subject: RE: AeroElectric-List: Ground jumping on Z-14 Thanks Bob, That is basically what I wanted verified. All the best, Chris Barber Houston Velocity 17010 "Only 38.9 more hours in Phase One Testing" :-) ________________________________________ From: owner-aeroelectric-list-server@matronics.com [owner-aeroelectric-list-server@matronics.com] on behalf of Robert L. Nuckolls, III [nuckolls.bob@aeroelectric.com] Sent: Tuesday, July 10, 2012 4:04 PM Subject: Re: AeroElectric-List: Ground jumping on Z-14 At 02:40 PM 7/10/2012, you wrote: Sorry if this is too basic but I am wondering about being able to jump start my Velocity. I missed this . . . if you want to actually crank the engine using ground power, you'll need a robust connector capable of carrying the current. You only need to connect it to the main battery in Z-14 . . . the aux battery gets connected too by closing the battery master switches and cross-feed contactors. Bob . . . ________________________________ Message 7 _____________________________________ Time: 06:46:54 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: OT: batteries in series on maintainer At 11:06 PM 7/10/2012, you wrote: Greetings, I recall a prohibition on charging batteries in series at the series voltage. I have 2 6V sealed lead/acid batteries. I would like to hook the series connected 6V batteries in parallel with several 12V lead/acid batteries on a maintainer. They would be fully charged before I put them on the maintainer. I would consider holding the voltage in the 6V batteries at 80% of full charge acceptable. I think those discussions were about putting two 12v batteries in series for 24v performance and the TAPPING the mid-point between the batteries to power 12v accessories. There's nothing fundamentally wrong with hooking batteries in series from the perspective of charging/discharging them. A 12v battery is a collection of 6 cells in series, a 24v battery has 12 cells. Whether all the cells are in the same enclosure is irrelevant. The caveats for series connection is that the size and condition of all cells in a series string be as closely matched to each other as practical. In other words, two identical batteries with different service histories are not good candidates for series connection. Similarly, batteries of different manufacture or capacity are at risk for diminished performance in a series connection. If your 6v batteries are charged/discharged as a matched pair from new to discard, they will perform well. This is true even if they are say charged in series but discharged in parallel. But if they are ever separated in the performance of duty as energy sources, then their "alikeness" begins to diverge and some amount of service life as a pair will be lost. That's all very non-quantified. There's no hard cause and effect numbers to be offered. Design goals for longest service life calls for treating all cells in a multi-cell system the same irrespective of their packaging. Bob . . . ________________________________ Message 8 _____________________________________ Time: 09:13:44 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: grounding procedures At 03:31 AM 7/11/2012, you wrote: > >Bob, > >Another thing to consider is what happens if/when the pump fails in >some way. Is it possible for the electrons to find a path that >would cause a problem? I don't have an answer, but it seems like >another possible way for bad things to happen. > >Raymond Julian >Kettle River, MN. The fuel is itself a non-conductor so things happening at the input end of a hose are not electrically relevant to things that occur at the other end. Static electricity is only loosely related to power electricity. While the earliest investigations into the nature of electrons involved the migration of electrons from one surface to another as static sources, none of these phenomenon produced a practical power sources. Static electricity is a byproduct of motion between two substances with dissimilar affinities for hanging onto their electrons. The substances need not be conductive. You can rub a balloon on cat's fur and generate an observable effect of electron migration in spite of the fact that the two materials are exceedingly poor conductors. Hence, the sources for static generation are limitless. The risks are obviously limited to the small sphere of conditions existing in the immediate vicinity of any exposed fuel, oxygen and potential ignition source. Risks are reduced when any number of the three components are removed from the mix. Single point fueling fixtures remove exposed fuel and air sources. So even if drew a healthy arc between the two fittings as they are mated or de-mated, risks for escalating combustion are zero. If your intent is to stick a delivery device into an open fuel tank, then care must be made to control the greatest risks (1) spillage and (2) ignition source that might ignite vapors. The whole grounding issue goes to control of ignition source. This can be vexing for combinations of plastic airplanes, non-conductive hoses, high rates of fuel flow, etc. Filling from a hand-held plastic fuel can does not represent a strong potential for an ignition source. Flow rates are low and there's no gathering point for a build-up of arc potential (like your fingertip approaching the door handle). Instances of fire when filling lawn mowers were the result of added risk for spillage over a hot engine that made the vapors hype-sensitive to tiny sparks that are happening all the time all around us anytime two non conductors move in close proximity to each other. The strongest prophylactic for unintended combustion has more to do with careful avoidance of spillage and high flow rates into the tank (through the same kind of hose used to put a full load on a King Air in minutes). Those same hoses MIGHT be a conductor of differential static potential between two LARGE capacitors . . . the surface of an airplane and the surfaces of a fuel truck. High flow rates into the tank cause both increased intensity of static buildup and outflow of vapors from the tank's heads pace. Adding a 'ground wire' inside a non-conducting fuel hose only serves to bring a connection from the static capacity of the delivery system out to the end of the hose. Adding such wire only INCREASES the need for grounding the delivery system to the airframe before approaching the filler neck with the end of the hose. Risks for a hand-held pour from a plastic 'can' is exceedingly low. Bob . . . ________________________________ Message 9 _____________________________________ Time: 10:52:46 AM PST US From: rayj Subject: Re: AeroElectric-List: grounding procedures Bob, I was thinking more along the lines of a failure of the electrical portion of the pump resulting in the pump body being energized and the electrons moving into the system designed to handle static charge. Similar to kind of event that the grounding wire in a 3 prong plug is designed to manage. Just a thought. Raymond Julian Kettle River, MN. "And you know that I could have me a million more friends, and all I'd have to lose is my point of view." - John Prine On 07/11/2012 11:12 AM, Robert L. Nuckolls, III wrote: > > > At 03:31 AM 7/11/2012, you wrote: >> >> Bob, >> >> Another thing to consider is what happens if/when the pump fails in >> some way. Is it possible for the electrons to find a path that would >> cause a problem? I don't have an answer, but it seems like another >> possible way for bad things to happen. >> >> Raymond Julian >> Kettle River, MN. > > The fuel is itself a non-conductor so things happening > at the input end of a hose are not electrically relevant > to things that occur at the other end. Static electricity > is only loosely related to power electricity. While the > earliest investigations into the nature of electrons involved > the migration of electrons from one surface to another > as static sources, none of these phenomenon produced > a practical power sources. > --------------------------- SNIP ----------------------------------- > Bob . . . > > ________________________________ Message 10 ____________________________________ Time: 03:23:59 PM PST US From: rayj Subject: Re: AeroElectric-List: OT: batteries in series on maintainer Bob, You're right, that was the conversation that I took an incorrect impression away from. Thanks for the info. do not archive Raymond Julian Kettle River, MN. "And you know that I could have me a million more friends, and all I'd have to lose is my point of view." - John Prine On 07/11/2012 08:46 AM, Robert L. Nuckolls, III wrote: > > > At 11:06 PM 7/10/2012, you wrote: > > Greetings, > > I recall a prohibition on charging batteries in series at the series > voltage. I have 2 6V sealed lead/acid batteries. I would like to hook > the series connected 6V batteries in parallel with several 12V lead/acid > batteries on a maintainer. They would be fully charged before I put > them on the maintainer. I would consider holding the voltage in the 6V > batteries at 80% of full charge acceptable. > -----------------SNIP ------------------------ > Bob . . . > ________________________________ Message 11 ____________________________________ Time: 03:31:39 PM PST US Subject: AeroElectric-List: Re: Z12 Alternator Amps From: "RV7ASask" I managed to get flying again today after turning the Aux Alternator regulator voltage up three turns. This worked. The voltage now shows 13.3 volts with the Main Alternator off. The high Amps, however, did not change. Prior to switching the Main Alternator off it was reading 8 Amps as before and adding up what was on, this was about right. With the Main off the Aux Alternator is still reading 20 Amps. At this point I do not think it has anything to do with the battery charging and I think everything is wired correctly. Still head scratching. Regards David Lamb Read this topic online here: http://forums.matronics.com/viewtopic.php?p=378037#378037 ________________________________ Message 12 ____________________________________ Time: 04:39:39 PM PST US From: Bob McCallum Subject: RE: AeroElectric-List: Re: Z12 Alternator Amps David; Amperage cannot just mysteriously appear or disappear. Are you sure that the shunt being used to measure this amperage is the correct one?? and that the instrument reading it is properly set up to interpret the shunt voltage correctly?? (your measurement instrument measures the voltage across the shunt then translates that into an amperage indication. The incorrect shunt will result in an erroneous indication as will a faulty translation calculation setup.) Bob McC > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list- > server@matronics.com] On Behalf Of RV7ASask > Sent: Wednesday, July 11, 2012 6:31 PM > To: aeroelectric-list@matronics.com > Subject: AeroElectric-List: Re: Z12 Alternator Amps > > > I managed to get flying again today after turning the Aux Alternator regulator voltage > up three turns. This worked. The voltage now shows 13.3 volts with the Main > Alternator off. > > The high Amps, however, did not change. Prior to switching the Main Alternator off it > was reading 8 Amps as before and adding up what was on, this was about right. With > the Main off the Aux Alternator is still reading 20 Amps. > > At this point I do not think it has anything to do with the battery charging and I think > everything is wired correctly. > > Still head scratching. > > Regards > David Lamb > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=378037#378037 > > > > > > > > _- > ==================================================== > ====== > _- > ==================================================== > ====== > _- > ==================================================== > ====== > _- > ==================================================== > ====== > > ________________________________ Message 13 ____________________________________ Time: 05:09:39 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Z12 Alternator Amps At 05:31 PM 7/11/2012, you wrote: > >I managed to get flying again today after turning the Aux Alternator >regulator voltage up three turns. This worked. The voltage now shows >13.3 volts with the Main Alternator off. > >The high Amps, however, did not change. Prior to switching the Main >Alternator off it was reading 8 Amps as before and adding up what >was on, this was about right. With the Main off the Aux Alternator >is still reading 20 Amps. Does it now go immediately to 20A instead of 'drifting up'? > > >At this point I do not think it has anything to do with the battery >charging and I think everything is wired correctly. > >Still head scratching. Okay . . . how about calibration issues. What kind of sensors do you have on the alternator b-leads, hall effect? . . . or are they shunts? What instrument displays the alternator current readings. One instruement that watches BOTH current signals or does it switch from one to the other? Bob . . . ________________________________ Message 14 ____________________________________ Time: 05:27:10 PM PST US Subject: Re: AeroElectric-List: grounding procedures From: bob noffs got a lot of good info from all the replies. i think i will go with the wire in the tube only because it is less likely to mar a finish. that wire will connect to metal tube in plastic can, the metal pump and the metal fuel filter on the airplane end. a ground wire from the exhaust pipes to the metal pump should make a spark impossible. am i missing something? the only other thing i can think of is to run a wire from the pump to the earth. would this serve any purpose? bob noffs On Wed, Jul 11, 2012 at 12:51 PM, rayj wrote: > > Bob, > > I was thinking more along the lines of a failure of the electrical portion > of the pump resulting in the pump body being energized and the electrons > moving into the system designed to handle static charge. Similar to kind of > event that the grounding wire in a 3 prong plug is designed to manage. > > Just a thought. > > > Raymond Julian > Kettle River, MN. > > "And you know that I could have me a million more friends, > and all I'd have to lose is my point of view." - John Prine > > > On 07/11/2012 11:12 AM, Robert L. Nuckolls, III wrote: > >> >> >> At 03:31 AM 7/11/2012, you wrote: >> >>> >>> Bob, >>> >>> Another thing to consider is what happens if/when the pump fails in >>> some way. Is it possible for the electrons to find a path that would >>> cause a problem? I don't have an answer, but it seems like another >>> possible way for bad things to happen. >>> >>> Raymond Julian >>> Kettle River, MN. >>> >> >> The fuel is itself a non-conductor so things happening >> at the input end of a hose are not electrically relevant >> to things that occur at the other end. Static electricity >> is only loosely related to power electricity. While the >> earliest investigations into the nature of electrons involved >> the migration of electrons from one surface to another >> as static sources, none of these phenomenon produced >> a practical power sources. >> >> --------------------------- SNIP ------------------------------**----- > > > Bob . . . >> >> >> >> >> >> > > ________________________________ Message 15 ____________________________________ Time: 05:44:56 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: grounding procedures At 12:51 PM 7/11/2012, you wrote: > >Bob, > >I was thinking more along the lines of a failure of the electrical >portion of the pump resulting in the pump body being energized and >the electrons moving into the system designed to handle static >charge. Similar to kind of event that the grounding wire in a 3 >prong plug is designed to manage. Grounds for the purpose of creating a safe-path for internal ground faults within a device are not expected to carry any great amount of current for long nor does the voltage during fault clearance time exceed that of the system . . I presume you have a 12vdc pump. Grounding of two "capacitors" (vehicle and airplane) to each other to prevent a difference in potential at the filler cap between nozzle and cap rim should be independent of and ground system provided for electrical fault clearance inside the pump motor. Single-point grounds for airplane and pump system might be the fuel truck chassis or even a grounding lug on the ramp (we had them all over the floor in the Experimental Flight Test Hangar) but you'd want to avoid daisy-chaining grounds. If the pump has been approved for fuel transfers then seals between fluid path and motor internals are pretty good . . . if non-existent (magnetic drive). The motor itself is probably qualified to high levels of explosion proof-ness (will totally contain products of combustion even if a stoichiometric mixture should become ignited within). The difference in voltage to be bled off is in the gap between fuel nozzle and the tank opening. This is best handled by a ground wire between these two points secured before the fuel tank is uncapped. The same ground is not removed before the cap is replaced and any spills wiped up. Nothing more exotic is necessary or useful. If it's a plastic airplane, then no 'grounding' is possible or necessary. This is an electro-static argument between your fuel delivery exit point and fuel tank entrance. That's where the oxygen-fuel source resides and where the ignition source must be prevented. All else is immaterial. Bob . . . ________________________________ Message 16 ____________________________________ Time: 06:47:31 PM PST US Subject: Re: AeroElectric-List: grounding procedures From: bob noffs soooooooooooo my tanks are grounded to my engine. am i safe to attach a wire from my fuel nozzle to my exhaust pipe or does the wire need to go to the tank filler neck? [that doesn't make sense to me] bob noffs On Wed, Jul 11, 2012 at 7:30 PM, Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > nuckolls.bob@aeroelectric.com**> > > At 12:51 PM 7/11/2012, you wrote: > >> >> Bob, >> >> I was thinking more along the lines of a failure of the electrical >> portion of the pump resulting in the pump body being energized and the >> electrons moving into the system designed to handle static charge. Similar >> to kind of event that the grounding wire in a 3 prong plug is designed to >> manage. >> > > Grounds for the purpose of creating a safe-path > for internal ground faults within a device > are not expected to carry any great amount of > current for long nor does the voltage during > fault clearance time exceed that of the system . . > I presume you have a 12vdc pump. > > Grounding of two "capacitors" (vehicle and airplane) > to each other to prevent a difference in potential > at the filler cap between nozzle and cap rim should > be independent of and ground system provided for > electrical fault clearance inside the pump motor. > Single-point grounds for airplane and pump system might > be the fuel truck chassis or even a grounding lug > on the ramp (we had them all over the floor in the > Experimental Flight Test Hangar) but you'd want > to avoid daisy-chaining grounds. > > If the pump has been approved for fuel transfers > then seals between fluid path and motor internals > are pretty good . . . if non-existent (magnetic > drive). The motor itself is probably qualified to > high levels of explosion proof-ness (will totally > contain products of combustion even if a stoichiometric > mixture should become ignited within). > > The difference in voltage to be bled off is in the > gap between fuel nozzle and the tank opening. This > is best handled by a ground wire between these two > points secured before the fuel tank is uncapped. > The same ground is not removed before the cap is > replaced and any spills wiped up. Nothing more exotic > is necessary or useful. If it's a plastic airplane, > then no 'grounding' is possible or necessary. > > This is an electro-static argument between your fuel > delivery exit point and fuel tank entrance. That's where > the oxygen-fuel source resides and where the ignition > source must be prevented. All else is immaterial. > > > Bob . . . > > ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.