---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 09/17/05: 14 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:39 AM - Re: Alternator field breaker (solution!) () 2. 07:01 AM - Re: magneto timing buzz box (Ron Brown) 3. 07:38 AM - Re: Re: Breaker Interrupt Rating (Robert L. Nuckolls, III) 4. 07:40 AM - Re: Re: Breaker Interrupt Rating (Robert L. Nuckolls, III) 5. 01:29 PM - Re: Re: Breaker Interrupt Rating (Paul Messinger) 6. 03:43 PM - Re: Re: Breaker Interrupt Rating (Chuck Jensen) 7. 04:33 PM - Re: magneto timing buzz box (Greg Campbell) 8. 04:47 PM - FW: Splice 6AWG Wire (Pete Howell) 9. 04:59 PM - Re: Re: Breaker Interrupt Rating (LarryRobertHelming) 10. 06:43 PM - Re: FW: Splice 6AWG Wire (KITFOXZ@aol.com) 11. 09:42 PM - Re: FW: Splice 6AWG Wire (Robert L. Nuckolls, III) 12. 09:43 PM - Re: Re: Breaker Interrupt Rating (Robert L. Nuckolls, III) 13. 09:44 PM - Re: Re: magneto timing buzz box (Robert L. Nuckolls, III) 14. 10:44 PM - Re: FW: Splice 6AWG Wire (rv-9a-online) ________________________________ Message 1 _____________________________________ Time: 12:39:08 AM PST US From: Subject: AeroElectric-List: Re: Alternator field breaker (solution!) --> AeroElectric-List message posted by: It sounds like just using an internally regulated alternator (I-VR) like a ND, is easier, simpler and more reliable. If we had cars that needed constant or even occasional circuit breaker resets or fuse replacement, we would have a line of angry people at the dealer and an investigative prime-time news show report. >Bob N.: ..your risk of intractable difficulties (with a crow bar) is low. With a ND alternator, if there is a problem the internal OV protection provides your protection, and YOUR RISK OF INTRACTABLE DIFFICULTIES IS LOW. However if there is some indication of problem, the integrated ALT fault light illuminates or an indication of Lo/Hi volts, manually pull the BIG-OL-FAT-CB on your panel (for the B-lead). I personally recommend** a B-lead CB on the panel that can be pulled and NOT a fuse. The use of a B-lead fuse is recommended on Z drawings, but the use of a CB on the B-lead is common aerospace practice and should be used when using a ND alternator. We know how great CBs are, because Bob recommends them in conjunction with a crow bar and has argued eloquently how reliable they are. Using Fuses on the B-lead is a special use on aircraft and common to automobiles but not airplanes. Also the issue of NOISE is over blown. A CB on the panel will NOT be the reason for electrical system noise. Back in the dark ages with old time external regulated alternators, using mechanical points, noise was an issue, regardless if you used a fuse or a CB on the panel. Modern alternators like the I-VR ND are not noisy. I have NOT heard alternator noise in a car since the 70's. New alternators of modern design used in cars and a single point central grounding wiring scheme in your aircraft will eliminate most if not all noise problems. If you have a ND alternator and hear noise in the audio system , remove the alternator and have it tested, repaired since it is not normal or fix a ground problem. Manually pulling the CB is totally OK with the CB, and it is a little more humane to the CB than throwing a dead short across it (not that there is anything wrong with that, I think?). I like having a way to disconnect the B-lead and isolating the alternator, regardless of where the voltage regulator is. PUT THAT BIG 40-60 AMP CIRCUIT BREAKER PROUDLY ON YOUR PANEL.** Pulling the B-lead CB on the panel isolates the alternator positively. There is no nuisance trips or worry of CB life. G ** All the above information is from a non-expert and should not be used unless you understand it and accept the fact (low risk) that a ND alternator failure will be a rare event. Further these rare failures will be benign. The extreme failure, where there is smoke and brimfire, of specific 40 amp and 60 amp ND alternator models mentioned on this list, are unsubstantiated, unconfirmed theory yet to be quantified and documented. Bob dont write me about paradigms. I am wrong and you are right and the "crow bar" is the best thing ever. I am crazy not to use it. Please, don't follow my advise/suggestions and do what Bob says. ________________________________ Message 2 _____________________________________ Time: 07:01:36 AM PST US From: "Ron Brown" Subject: Re: AeroElectric-List: magneto timing buzz box --> AeroElectric-List message posted by: "Ron Brown" I have successfully timed the Slick mag on my Lycoming IO360 using a digitial ohm meter than can resolve 0.1 ohm. I have a $50 Radioshack meter similar to http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&category%5Fname=CTLG%5F011%5F008%5F002%5F000&product%5Fid=22%2D812 If you have a digital ohm meter that will display ohms in 0.1 ohm increments, it should work too. MAKE SURE THERE IS NO FUEL IN THE FUEL/CARB. THE REALLY SAFE WAY TO DO THIS IS TO REMOVE ONE PLUG FROM EACH CYLINDER. CAUTION - DO NOT HAVE THE OHM METER CONNECTED WHILE THE IMPULSE COUPLING SNAPS - GOOD CHANCE YOU WILL DAMAGE YOUR OHM METER DUE THE HIGH ENERGY AT THE P LEAD WHEN THE MAG FIRES. 1. Turn the engine in the normal direction until the impulse coupling snaps - #1 firing position - can be verified by holding your finger over the #1 spark plug hole and turn until you get pressure. 2. Turn the prop back wards about 45 degrees. 3. Turn the ignition switch on. Connect one lead of the ohm meter to the P lead for the mag. (I actually connect to the back of my mag/starter switch - easier to get to in my plane). 4. Connect the other ohm meter lead the engine case. 5. My meter shows 0.7 ohms with the points closed. 6. Now, very slowly move the prop in the counter clockwise direction until the resistance changes to 0.4- 0.5 ohms. You will need to let the ohm meter settle for a couple of seconds after each movement - the mag will supply some voltage when it is moving. 7. The timing marks are in two locations. On the front of the flywheel facing the engine case split. Mine has markings at 0 TDC, 22 BTDC, and 25 BTDC (before top dead center). 8. The other mark is on the starter ring - and there is a dimple on the upper starter flange that is the zero point. The dimple on the starter ring is covered up by the prop extension cover - but I made a mark out on the ring gear it self. 9. TURN THE IGNITION BACK OFF, REMOVE THE DVM, PRIOR TO TURNING THE ENGINE PAST THE FIRING POINT!!! I have verified this works - two A&P's and their two buzz boxes were used to verify my indications were correct. Of course, if you have access to the buzz boxes, by all means use it instead. But if you have a good DVM, you can use it instead. WORKS!!! Ronnie Brown ________________________________ Message 3 _____________________________________ Time: 07:38:57 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: RE: Breaker Interrupt Rating --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 10:39 PM 9/16/2005 -0500, you wrote: >--> AeroElectric-List message posted by: Charlie England > > >Eric M. Jones wrote: > > >--> AeroElectric-List message posted by: "Eric M. Jones" > > > > > >Safety hazards include not setting the local surroundings afire. I used to > >sell crowbar OVPs similar to Bob's. Part of my test fixture was a Tyco P&B > >Series W28 10A Thermal Circuit Breaker purchased from Digikey. On the first > >test with a 24V battery as OV, the circuit breaker opened but failed > >catastrophically. Since the OVP test setup was not a perfect reflection of > >the real world, I discounted the incident, but later decided to not sell > >crowbar type OVPs at all. Aha! DATA! now can you share any measurements you took? Wire sizes and lengths? > > > >Paul Messinger's 400A measurement used a setup that was an exact duplicate > >(wire lengths and all) of his aircraft's system. In order for a CB to be > >rated as "interrupted without damage", it usually only has to do this 3X. Really? Again, tell me how I can go to the bench and duplicate his experiment. Bob . . . ________________________________ Message 4 _____________________________________ Time: 07:40:02 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: RE: Breaker Interrupt Rating --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 10:42 AM 9/16/2005 -0400, you wrote: >--> AeroElectric-List message posted by: "Eric M. Jones" > >--> AeroElectric-List message posted by: "Matt Prather" > >Matt-- > > > You might say that calibration and operating performance applies to the > > behavior during only one firey interrupt. However, the calibration curve > > only goes to 1000x the rating. > >Please look again. That's 10X the rating or 1000%. Bob claims the curves >can be extended. This is a fundamental disagreement. Paul and Eric call the upper bounds the set of curves limits that should not be exceeded if one is desirous of not "killing" one's breaker. I have a brother in law who became a journeyman electrician and while helping me with some wiring one day, decided that after we had a breaker open on a miss-wired feeder, that it should be replaced. I asked why and he stated that's what he was taught. That was 20 years ago and the same breaker is still in the box. >Another problem is how the device will operate at 12V when the trip times >are for 28V. ???12v versus 28v trip times??? Opening time is an I(squared)*T event that is independent of voltage. Once the latch opens and contact start to move, it's no longer a beaker but a simple switch. Now the physics focus on contact spreading velocity, contact mass and characteristics of load current (resistive, inductive, lamp or some combination of all three) and SYSTEM VOLTAGE. > There is an important alloy difference in contacts good for 12 and 28 volts. Really? Where do you find this on the data sheets . . . or any other document for that matter? >I don't know, but I can imagine a scenario where the contacts would weld >without sufficient heat to cause the bimetal strip to flex enough. At any >rate, it is wrong to think a device specified for 28V will "work fine" at >12-14V. It is also wrong to think that AC applications are more rigorous >than DC. We should consider two separate activities that go on within a breaker: Heat energy dissipated in the current sensor sufficient (1) raise the temperature of the trip mechanism so that (2) a set of switch contacts are caused to open. The trip time is relatively constant irrespective of operating voltage. Temperature rise in the heater is an RMS current and time dependent effect and doesn't care about ac/dc or voltage. The opening the contacts after trip time is where voltage and circuit characteristics matter. It's immaterial whether we consider switches, relays or breakers for this study . . . all three devices need to break a circuit where voltage, source impedance and dynamics (ac/dc) can have an effect on success for any single event and also drives total number of high-stress openings that can be endured before the breaker's SWITCH performance is degraded. >Paul Messinger's tests show that the discharge can be far greater than the >CB is spec'd for. This devolved into an argument about battery >resistances, but I believe Paul (since I am somewhat party to his testing). About which we know nothing. I've published everything I've done on the bench and you've published nothing. Let's talk about specs . . . For example, I could publish a set of curves for any number of products to aid the user in predicting performance over a range of conditions I might anticipate to be common. The fact that my charts and curves end at some particular boundary does not have to mean that venturing outside that boundary is automatically deleterious to the product. > > Datasheets exist to cover the backsides of the producer, but also to > > provide useful information about how to apply a product correctly. > > > If a breaker isn't reusable after a real-world hard fault, that's one > of the industry's best-kept dirty little secrets. > >CBs fail all the time, but less so when they are properly located in real >systems. In the worst case fault a CB only has to work three times to be >approved for that current. "Crowbar" usage is a special application. There >are plenty of guys using two motorcycle batteries in parallel, or newer >batteries with phenomenal cranking capabilities. I believe Paul's 400 Amp >result would be easy to get, and the CB is not correct for the >application. Adding a resistor seems easy but requires a pulse rated part. This battery impedance thing keeps coming up . . . Assume ZERO impedance and then wire per the diagrams and we still can't approach a 400A (started out 700A) mark. Go to the bench my friend. Show me how you get a real 400A event . . . or even a real 200A event. Gather the data and we'll add it to: http://www.aeroelectric.com/articles/Crowbar_OV_Protection/DC_Power_System_Dynamics_C.pdf This article describes the kind of testing and thought processes behind the original design. Make my day, show me where we were wrong. When the crowbar ov module is wired per any of the diagrams I've ever posted, the resulting stresses for crowbar operation do not overstress any breakers I've used or would recommend. The P&B W31 series switch/breakers have been used in Bonanzas and Barons for decades. When we qualified the crowbar ov system onto the turbine powered Bonanza (Lightning) 25 years ago, the same spec sheet was in force: http://www.aeroelectric.com/Mfgr_Data/Breakers/Potter_Brumfield/W2331_DS.pdf Yup, there's a bunch of performance limit specs for interrupt capacity . . . at 50V (Which are conservative). We determined that the real stresses on the breaker for the relatively high crowbar interrupt events was not related to stresses on the heater but on the contact's ability to break the arc . . . which is much more difficult to do at 50VDC (I'm told this is one of big stumbling blocks for a transition to 42V cars . . . arcs start easier and are harder to put out). Beech had a requirement that an ovp system function properly after 50 cycles for qualification purposes. We did engineering testing to hundreds of cycles in 28V systems and determined that the technology was sound. It's even sounder in 14V systems. >You can't test the crowbar design into a good design. "Good" is non quantified. There was no testing done to change the physics. Testing was done to discover the physics we suspected or confirm the physics we already knew. Testing showed that design goals were met without measurable effect on either reliability or performance of the parts used. Opening a 5A breaker with a 150A event does not hurt the heater and contacts of every breaker I've run across. Every breaker tested will open the 150A event hundreds of times without degrading performance. Given that an ov event should be extremely rare (most airplanes will never have one) the confidence level in our investigations was high enough to call the technology certifiable. We do testing all the time to confirm what we know. For example, you can't buy military temp rated parts any more. Nonetheless, we have many requirements to guarantee operation at -55 to +105C. The parts were all made on the same production line and simply screened for the wider operating ranges. We still meet our extended temperature range requirements by TESTING industrial rated parts ourselves. If I could find a breaker manufacturer willing to deliver to a Critical Item Product Function Specification for a breaker that meets my requirements for operation in a crowbar ovp system, they would probably charge me $100,000 for qual testing. Then, the price of what used to be a $15 breaker would now be $100 and guess what? The breaker supplied would most likely come right off their present production line but with a different part number on it. What we're really discussing here is a difference in philosophies. You prefer to interpret specification sheet data as brick walls . . . this is certainly a minimum effort, minimum risk decision. I, and many of my compatriots, understand that components may have capabilities that range well outside published data. Capabilities that can be exploited to good advantage . . . but only if you take the time to understand the simple-ideas that govern the way the part functions. You're certainly within your rights to design within the boundaries suggested by your interpretation of data sheets. But this does not make my design decisions bad or un-desirable because I choose to exploit unspecified but acknowledged and testable capabilities that lie outside the published values. I'd still like to see how one gets 400A to flow through a 5A breaker of any manufacturer. Paul alluded to a 5A breaker with some very low (.004 ohms I think) resistance awhile back. I'd give him $50 for a sample of such a part. But alas, we're still in the dark as to parts tested, test setups crafted, tests conducted, and data derived therefrom. To date, your arguments are supported only by your conservative interpretation of data sheets. > > None the less, maybe you're right, and Rutan is right. Minimum specs > end up being performance ceilings. > > >Agreed. But consider that in a mature product the performance tolerance is >so small that it does not encourage improvement in the product. This is >the best that can be done in a particular design. And it's a good thing, >not a bad thing. ????? What does this mean? Bob . . . ________________________________ Message 5 _____________________________________ Time: 01:29:04 PM PST US From: "Paul Messinger" Subject: Re: AeroElectric-List: RE: Breaker Interrupt Rating --> AeroElectric-List message posted by: "Paul Messinger" Bob; I DID post (to this list) the exact specific technical parts etc. details of my test and you seemed never recognize that fact. That I used words and not a schematic is not important in this case as a schematic is not needed with such a simple circuit. I did use a different wiring diagram (of your schematic) to duplicate what is in my aircraft however. But you cannot duplicate my results (as I under stand what you mean by duplicate) unless you use the exact same parts I used. The same identical part, not a part of the same brand and part number is required in this case because of the very wide variation in the parts tolerances. Only if a worst case analysis is properly done and the range of test results is determined can any test be duplicated by another using different physical parts of the same part number. The part to part variation in most cases and clearly in this case is simply too large. Crow bar short circuit currents can vary from well under 100 amps to over 400 amps depending on the parts used and the wiring diagram used to implement the same schematic. Thus any test that results in a current from around 100 amps to around 400 amps is in fact a duplication of another's test results in this case. Where there are small parts variations the duplicated test results will be much closer but NEVER identical. For example the following is true: #1 CB ratings vary widely in resistance and trip time, in fact, close to a 10 -1 variation. between parts of the same brand and parts from other brands. Nothing strange about My CB having an internal resistance 1/10 of the one you used. CB internal resistance can and does vary from approx 0.003 to over 0.030 ohms; a 10-1 variation #2 Battery internal resistance also varies again as much as 10-1 depending on the battery brand and ratings. My batteries have 1/5 to 1/10 the internal resistance of your battery. But then I do not use the Panasonic brand or similar types.I do use a very popular PS625 (dual at that) battery with much higher specifications in most important parameters. Not that the Panasonic is bad but its not nearly the same in several (important to me) electrical specifications. #3 My wiring was an exact duplicate of what I have in my aircraft and is a fraction of what you had in your test. My wiring is less that 1/2 the internal resistance of your test wiring. I measures the battery internal resistance as well as the CB and wiring resistances before and after the testing series. The same CB was used in the simulated worst case test where the current was 700 amps and there were at least 50 tests of the real circuit where the current was 400 amps. No degrading of any part including the SCR in your crow bar circuit which was over stressed several times its max rating. This overstressing and lack of damage does not mean its a good design idea and more importantly does not mean that all CB's will survive with no damage. In this case the main short current drivers are the Battery, CB and wiring resistances. That alone suggests that 400 amps is easy to achieve as the circuit resistance to get 400 amp vs. 130 amps only needs to decrease to 1/3 or so. Bottom line: I had 6 EXPERT, experienced, real electrical engineers review what I have done and ALL agreed with my test setup and suggested 400 amps was not the max current possible as I had not used the worst case analysis parts. I had hoped this issue had gone away months ago as we will never agree. I only post here when I feel my comments are being misquoted to the extreme. Seems that will never end and frankly I am saddened that it seems to continue. The basic issue of OVP crow bar short to open a CB is the real discussion where you believe its a good approach and I disagree is the fundamental issue and the short current is a distraction. Please do not snip this email as it tends to put my comments out of context and change the meaning/intent of my comment. Better yet simply do not reply and we can both put this stupid debate to rest and get on with productive discussions. Paul ----- Original Message ----- From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: RE: Breaker Interrupt Rating > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > Really? Again, tell me how I can go to the bench and duplicate > his experiment. > > Bob . . . ________________________________ Message 6 _____________________________________ Time: 03:43:12 PM PST US Subject: RE: AeroElectric-List: RE: Breaker Interrupt Rating From: "Chuck Jensen" --> AeroElectric-List message posted by: "Chuck Jensen" Fire in the hole! Do Not Archive -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Paul Messinger Subject: Re: AeroElectric-List: RE: Breaker Interrupt Rating --> AeroElectric-List message posted by: "Paul Messinger" Bob; I DID post (to this list) the exact specific technical parts etc. details of my test and you seemed never recognize that fact. That I used words and not a schematic is not important in this case as a schematic is not needed with such a simple circuit. I did use a different wiring diagram (of your schematic) to duplicate what is in my aircraft however. But you cannot duplicate my results (as I under stand what you mean by duplicate) unless you use the exact same parts I used. The same identical part, not a part of the same brand and part number is required in this case because of the very wide variation in the parts tolerances. Only if a worst case analysis is properly done and the range of test results is determined can any test be duplicated by another using different physical parts of the same part number. The part to part variation in most cases and clearly in this case is simply too large. Crow bar short circuit currents can vary from well under 100 amps to over 400 amps depending on the parts used and the wiring diagram used to implement the same schematic. Thus any test that results in a current from around 100 amps to around 400 amps is in fact a duplication of another's test results in this case. Where there are small parts variations the duplicated test results will be much closer but NEVER identical. For example the following is true: #1 CB ratings vary widely in resistance and trip time, in fact, close to a 10 -1 variation. between parts of the same brand and parts from other brands. Nothing strange about My CB having an internal resistance 1/10 of the one you used. CB internal resistance can and does vary from approx 0.003 to over 0.030 ohms; a 10-1 variation #2 Battery internal resistance also varies again as much as 10-1 depending on the battery brand and ratings. My batteries have 1/5 to 1/10 the internal resistance of your battery. But then I do not use the Panasonic brand or similar types.I do use a very popular PS625 (dual at that) battery with much higher specifications in most important parameters. Not that the Panasonic is bad but its not nearly the same in several (important to me) electrical specifications. #3 My wiring was an exact duplicate of what I have in my aircraft and is a fraction of what you had in your test. My wiring is less that 1/2 the internal resistance of your test wiring. I measures the battery internal resistance as well as the CB and wiring resistances before and after the testing series. The same CB was used in the simulated worst case test where the current was 700 amps and there were at least 50 tests of the real circuit where the current was 400 amps. No degrading of any part including the SCR in your crow bar circuit which was over stressed several times its max rating. This overstressing and lack of damage does not mean its a good design idea and more importantly does not mean that all CB's will survive with no damage. In this case the main short current drivers are the Battery, CB and wiring resistances. That alone suggests that 400 amps is easy to achieve as the circuit resistance to get 400 amp vs. 130 amps only needs to decrease to 1/3 or so. Bottom line: I had 6 EXPERT, experienced, real electrical engineers review what I have done and ALL agreed with my test setup and suggested 400 amps was not the max current possible as I had not used the worst case analysis parts. I had hoped this issue had gone away months ago as we will never agree. I only post here when I feel my comments are being misquoted to the extreme. Seems that will never end and frankly I am saddened that it seems to continue. The basic issue of OVP crow bar short to open a CB is the real discussion where you believe its a good approach and I disagree is the fundamental issue and the short current is a distraction. Please do not snip this email as it tends to put my comments out of context and change the meaning/intent of my comment. Better yet simply do not reply and we can both put this stupid debate to rest and get on with productive discussions. Paul ----- Original Message ----- From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: RE: Breaker Interrupt Rating > --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" > > Really? Again, tell me how I can go to the bench and duplicate > his experiment. > > Bob . . . ________________________________ Message 7 _____________________________________ Time: 04:33:18 PM PST US From: "Greg Campbell" Subject: AeroElectric-List: Re: magneto timing buzz box --> AeroElectric-List message posted by: "Greg Campbell" Take a look at the $25 kit from www.MagnetoTimer.com and see if that meets your needs. I've built two - it's a fun little soldering project, all the parts are included and identified (taped to the instruction sheet). About an hour of fitting & soldering and you've got a nice tool. The leads coil up and stow inside the open front of the plastic case. Greg ________________________________ Message 8 _____________________________________ Time: 04:47:17 PM PST US From: "Pete Howell" Subject: AeroElectric-List: FW: Splice 6AWG Wire --> AeroElectric-List message posted by: "Pete Howell" I have one of the in-line maxifuse holders wirth 6AWG wire. One lead is not long enough. How is the best way to splice in a longer piece of 6AWG? ________________________________ Message 9 _____________________________________ Time: 04:59:05 PM PST US From: "LarryRobertHelming" Subject: Re: AeroElectric-List: RE: Breaker Interrupt Rating --> AeroElectric-List message posted by: "LarryRobertHelming" > Fire in the hole! > > Do Not Archive Now I remember why I put Paul on my ignore list. I think it was a good idea after reading this copy. I really have lost my enthusiasm for the energy it takes to try and stay with Paul. Paul has his way and no other. He does not honor any of us with his stubborn ways I think. Paul, you say it is so simple to explain in words yet (too complicated to explain with a diagram.) ?? I AM too dumb to understand that. My I suggest: The key to winning me over to your ideas, Paul, is to communicate your ideas clearly. Give Bob just a smithering of a break here, how can a diagram not provide proof and the needed details of what you are talking about? Indiana Larry ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ " Happiness: like a butterfly, when pursued, is always beyond our grasp, but which, if one sits quietly, may light upon you." Nathaniel Hawthorne ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ----- Original Message ----- From: "Chuck Jensen" Subject: RE: AeroElectric-List: RE: Breaker Interrupt Rating > --> AeroElectric-List message posted by: "Chuck Jensen" > > > Fire in the hole! > > Do Not Archive > > -----Original Message----- > From: owner-aeroelectric-list-server@matronics.com > [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Paul > Messinger > To: aeroelectric-list@matronics.com > Subject: Re: AeroElectric-List: RE: Breaker Interrupt Rating > > --> AeroElectric-List message posted by: "Paul Messinger" > > > Bob; > > I DID post (to this list) the exact specific technical parts etc. > details of > my test and you seemed never recognize that fact. That I used words and > not > a schematic is not important in this case as a schematic is not needed > with > such a simple circuit. I did use a different wiring diagram (of your > schematic) to duplicate what is in my aircraft however. > snip ________________________________ Message 10 ____________________________________ Time: 06:43:56 PM PST US From: KITFOXZ@aol.com Subject: Re: AeroElectric-List: FW: Splice 6AWG Wire --> AeroElectric-List message posted by: KITFOXZ@aol.com In a message dated 9/17/2005 7:48:16 P.M. Eastern Standard Time, pete.howell@gecko-group.com writes: I have one of the in-line maxifuse holders wirth 6AWG wire. One lead is not long enough. How is the best way to splice in a longer piece of 6AWG? Hello Pete, There are a few ways to splice wires of that size. My choice would be to solder them but, most guys would not have a soldering iron large enough for the job. You would need an iron with a chisel tip and about 120 Watts of heat. The Weller SP120 would be a good choice. Strip the insulation off the wires about 1/2" to 3/4" and "merge" them into one another by spreading the strands a bit and inserting them into each other. A wrap of some small (20-22 ga.) copper wire around the joint will hold them for soldering. The trick is to melt a little solder on the iron tip and hold it to the joint and wait. The heat will transfer to the joint in a short time through the molten contact point. Add solder as needed until the joint is saturated. Clean flux away when cool and slide on a layer or two of heat shrink wrap available at Lowes or Home Depot etc. There are crimp-on butt splices available for the job or you could crimp and or solder some ring terminals to the ends and then "bolt" them together. Crimping any terminal or splice that large is tricky without the right crimping tools. If you buy a soldering iron large enough for the job instead of a crimping tool you'll have an iron large enough to fix the radiator in your wife's car. --Bonus in my book! John P. Marzluf Columbus, Ohio Outback, (out back in the garage) ________________________________ Message 11 ____________________________________ Time: 09:42:41 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: FW: Splice 6AWG Wire --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 09:42 PM 9/17/2005 -0400, you wrote: >--> AeroElectric-List message posted by: KITFOXZ@aol.com > > >In a message dated 9/17/2005 7:48:16 P.M. Eastern Standard Time, >pete.howell@gecko-group.com writes: > >I have one of the in-line maxifuse holders wirth 6AWG wire. One lead is not >long enough. How is the best way to splice in a longer piece of 6AWG? John. Great answer. I was going to suggest the same thing. The size of the soldering tool may not have to be a 'hog' . . . First, you'll find that 6AWG aircraft wire is made up of 137 total strands 27AWG wire that is layered over a center "rope" of 19 strands. Each layer is twisted in a direction opposite that of the adjacent layer. You won't be able to simply fan and push strands of wires together. The fuseholder is automotive and may be as few as seven strands but probably more. Step 1 is to "cone out" all strands of both wires and use needle nose plier to reasonably straighten each strand. The strip-length for each wire is about 1". Now, overlap about 3/4" of one wire's strands into the other and work down the fanned out cone of wires on both sides toward a smooth, intermeshed cylinder of all strands. I recommend a piece of the smallest safety wire you have. You want a fixture wire that does not solder into the finished joint. Monel or stainless wire will hold things together while you solder and remain free of joint so it can be removed later. Start right at insulation on one wire and put a couple of turns of safety wire on in close pitch. Then move wrapping over to first-second third of overlap for a couple of turns. Next put a couple turns at second-third third of overlap. Finish up with a few turns outside the overlap on the other wire. You want gaps between the five fixture-wraps to feed solder into the joint and observe wetting of the strands. Now, if you have a really efficient iron (like the Metcal series) you can easily solder this size wire with the 35 watt tool. Alternatively, check out your local Home Depot or Lowes for a Bernz-O-Matic ST100T butane torch. They sell for about $10 and you'll need a $4 fuel cannister. http://tools.batauto.com/index.php?crn=234&rn=1123&action=show_detail&PHPSESSID=cdea544011802efadd1901040779d172 This is a very hi quality alternative to a pencil butane torch found in hobby shops and Harbor Freight. I give these BernzOMatic torches away at my weekend seminars. Use some 60/40 or 63/37 electronic solder to join strands of the wires. Oh, yes . . . be sure to put 1 or 2 chunks of heatshrink on the pigtails BEFORE you begin all this. It may be VERY hard to put it on later! After the joint cools, peel the safety wire off, check for little sharp "tits" on the wire or possible exposed strand ends that might puncture the heatshrink. Cover your finished and smoothed joint with a couple layers of heatshrink and you're done. I'll go get the stuff to do a comic book on this tomorrow sometime. Bob . . . >Hello Pete, > >There are a few ways to splice wires of that size. My choice would be to >solder them but, most guys would not have a soldering iron large enough >for the >job. You would need an iron with a chisel tip and about 120 Watts of heat. >The Weller SP120 would be a good choice. Strip the insulation off the wires >about 1/2" to 3/4" and "merge" them into one another by spreading the >strands a bit and inserting them into each other. A wrap of some small >(20-22 ga.) >copper wire around the joint will hold them for soldering. > >The trick is to melt a little solder on the iron tip and hold it to the >joint and wait. The heat will transfer to the joint in a short >time through the >molten contact point. Add solder as needed until the joint is saturated. >Clean flux away when cool and slide on a layer or two of heat shrink wrap >available at Lowes or Home Depot etc. > >There are crimp-on butt splices available for the job or you could crimp and >or solder some ring terminals to the ends and then "bolt" them together. >Crimping any terminal or splice that large is tricky without the right >crimping >tools. > >If you buy a soldering iron large enough for the job instead of a crimping >tool you'll have an iron large enough to fix the radiator in your >wife's car. >--Bonus in my book! > >John P. Marzluf >Columbus, Ohio >Outback, (out back in the garage) > > >-- > > >-- incoming mail is certified Virus Free. Bob . . . -------------------------------------------------------- < Throughout history, poverty is the normal condition > < of man. Advances which permit this norm to be > < exceeded -- here and there, now and then -- are the > < work of an extremely small minority, frequently > < despised, often condemned, and almost always opposed > < by all right-thinking people. Whenever this tiny > < minority is kept from creating, or (as sometimes > < happens) is driven out of a society, the people > < then slip back into abject poverty. > < > < This is known as "bad luck". > < -Lazarus Long- > <------------------------------------------------------> http://www.aeroelectric.com ________________________________ Message 12 ____________________________________ Time: 09:43:42 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: RE: Breaker Interrupt Rating --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 01:02 PM 9/17/2005 -0700, you wrote: >--> AeroElectric-List message posted by: "Paul Messinger" > >Bob; > >I DID post (to this list) the exact specific technical parts etc. details of >my test and you seemed never recognize that fact. Forgive me. I WAS watching for such information since I was the one who requested it. Can you give me an approximate date or repeat your post. I'll so search the archives if necessary. Give me one part number you cited. It will make the search so much faster. > That I used words and not >a schematic is not important in this case as a schematic is not needed with >such a simple circuit. I did use a different wiring diagram (of your >schematic) to duplicate what is in my aircraft however. Then is it a fair presumption that as an skilled and articulate engineer that you've documented that portion of your system's wiring in a manner that can be scanned and shared? >But you cannot duplicate my results (as I under stand what you mean by >duplicate) unless you use the exact same parts I used. The same identical >part, not a part of the same brand and part number is required in this case >because of the very wide variation in the parts tolerances. Absolutely! I've never done a test report without identifying or at least making full disclosure of parts used, techniques, measurements, etc. I'd be pleased for you to take the parts I used in http://www.aeroelectric.com/articles/Crowbar_OV_Protection/DC_Power_System_Dynamics_C.pdf and show me how I mis-read or mis-interpreted data at the risk of making a bad deduction. You seem to accept the test results I posted but counter with "that's not what I got with MY test." Fine . . . tell us how you did it. >Only if a worst case analysis is properly done and the range of test results >is determined can any test be duplicated by another using different physical >parts of the same part number. The part to part variation in most cases and >clearly in this case is simply too large. I'm mystified as to this part-to-part variation you cite. >Crow bar short circuit currents can vary from well under 100 amps to over >400 amps depending on the parts used and the wiring diagram used to >implement the same schematic. I don't doubt it . . . but I'm still trying to visualize the 400A case. >Thus any test that results in a current from around 100 amps to around 400 >amps is in fact a duplication of another's test results in this case. > >Where there are small parts variations the duplicated test results will be >much closer but NEVER identical. You don't have to sell me on stacked up variability and test tolerances . . . I've been doing this since high school physics. >For example the following is true: > >#1 CB ratings vary widely in resistance and trip time, in fact, close to a >10 -1 variation. between parts of the same brand and parts from other >brands. Nothing strange about My CB having an internal resistance 1/10 of >the one you used. CB internal resistance can and does vary from approx 0.003 >to over 0.030 ohms; a 10-1 variation This I really need to see. What brand and part number exhibits such variability? The problem I'm having is that trip characteristics are an I(squared)*T event that depends on heat generated within the current sensing part of the breaker. ANY breaker that shows a 10:1 variability in resistance should be expected to show a similar variability in trip characteristics. There are no manufacturers I work with that would offer me such a product. Gee, a 5A breaker that can open anywhere between 2.5 and 25 amps! >#2 Battery internal resistance also varies again as much as 10-1 depending >on the battery brand and ratings. My batteries have 1/5 to 1/10 the internal >resistance of your battery. But then I do not use the Panasonic brand or >similar types.I do use a very popular PS625 (dual at that) battery with much >higher specifications in most important parameters. Not that the Panasonic >is bad but its not nearly the same in several (important to me) electrical >specifications. As I've repeated many times, I don't care if your battery is ZERO ohms. There's a rational, recommended installation technique for using my products where the MAJOR contributor of loop resistance is wiring, a minor contributor is circuit breaker heater resistance with so small an amount coming from the battery and fatwires that they can be ignored. Nonetheless, I'm intently interested in your .0035 to .0017 ohm battery. Do I recall that you're building a Subaru powered two-place? Batteries I can find with this level of performance start out at 60 pounds and go up from there. I presume you ARE planning on carrying passengers in this airplane . . . >#3 My wiring was an exact duplicate of what I have in my aircraft and is a >fraction of what you had in your test. My wiring is less that 1/2 the >internal resistance of your test wiring. Very good. The systems I recommend and illustrate in the Z-figures are rooted in practices found in the vast majority of Certified and OBAM iron. Of course one should not toss away lots of performance in wire drops and soggy batteries . . . but then, wiring everything with 00 gage and installing batteries that would crank a Detroit Diesel in a N. Dakota winter has some seriously diminished returns on overall system design. If you have 1/2 the loop resistance illustrated in my experiments, you must have a rational for increased battery and wire sizes at the sacrifice of useful load. We'd be interested in understanding the design goals by which you arrived at this exceedingly low loss system. >I measures the battery internal resistance as well as the CB and wiring >resistances before and after the testing series. > >The same CB was used in the simulated worst case test where the current was >700 amps and there were at least 50 tests of the real circuit where the >current was 400 amps. No degrading of any part including the SCR in your >crow bar circuit which was over stressed several times its max rating. Then no doubt you can tell me what the battery part number was, what circuit breaker was used, what SCR was used, what diameters and lengths of wires were used . . . I'll pay you my consulting fee for the time it takes you to type that data into a posting here on the list. >This overstressing and lack of damage does not mean its a good design idea >and more importantly does not mean that all CB's will survive with no >damage. > >In this case the main short current drivers are the Battery, CB and wiring >resistances. > >That alone suggests that 400 amps is easy to achieve as the circuit >resistance to get 400 amp vs. 130 amps only needs to decrease to 1/3 or so. > >Bottom line: I had 6 EXPERT, experienced, real electrical engineers review >what I have done and ALL agreed with my test setup and suggested 400 amps >was not the max current possible as I had not used the worst case analysis >parts. Then may we expect to see their names on the byline for a detailed report? As long you've opened the door to name dropping, I'll claim real signatures of dozens of folks representing systems designers, DERs, program managers, test pilots and test technicians who executed paperwork certifying this system on Mooney, Piper, Beech, Cessna and Cirrus aircraft. This is over and above thousands of OBAM aircraft customers who seem to be getting satisfactory performance from their purchases. For the moment, I have no greater assurances of the existence of your six "experts" than I do of the half dozen or so of my customers you claim were ALL having nuisance trip problems NONE of whom would call me for assistance and ALL of which declined an opportunity to exercise my well published 100% satisfaction or money back guarantee. >I had hoped this issue had gone away months ago as we will never agree. I >only post here when I feel my comments are being misquoted to the extreme. >Seems that will never end and frankly I am saddened that it seems to >continue. The List is a classroom. Folks will always be asking about these issues and as one of several teachers on the list, I have a duty to sort myth, old mechanic's tales, and bad science from fact as I understand it. If you want this discussion to end, then carry out your past threats never to post again. If you have facts to dispute, then be a teacher and publish counter balancing facts. Either is fine with me . . . but don't expect me not to continue to counter rumors, yours or anyone else's. I'm sure Greg Richter is fond of telling tales over a beer about how he crossed swords with that wild-eyed guy in Wichita and the telling probably gets better with each pitcher full. He too was amazingly reluctant to answering a single direct question. If you're ready to mark me off as hopeless, you're welcome to bow out . . . I've even offered $cash$ rewards for simple answers to specific questions. It would be worth it to me. My exorbitant consulting rate at the moment is $75/hour. If you could save me a hour of time digging around trying to figure out exactly how you arrive at some of your mystifying numbers, then I'd be money ahead to pay you cash for the data. I'd rather use the hour to add value to someone's airplane as opposed to sorting your jigsaw puzzle with many missing pieces. How about filling in your version of the pieces in the first figure on page 2 of the paper cited above and show us all how you generated a 400A crowbar event? >The basic issue of OVP crow bar short to open a CB is the real discussion >where you believe its a good approach and I disagree is the fundamental >issue and the short current is a distraction. Hmmm . . . at least it's devolved to a 'distraction' . . . there have been times past when the crowbar event could be expected to cause all manner of bad day including in-flight reset of EFIS systems and engine stoppage. If you have a better approach, you're most welcome to join the rest of us in the free marketplace. >Please do not snip this email as it tends to put my comments out of context >and change the meaning/intent of my comment. > >Better yet simply do not reply and we can both put this stupid debate to >rest and get on with productive discussions. If it's stupid, it's only because you're not debating. Any high school debate teacher would have tossed you out of this classroom years ago. My physics teacher would have tossed you out of his class too. I saw him do it to a kid that "dry labbed" an important assignment. This is not a classroom on debate, it's a classroom of simple ideas and physics as they relate to building the best airplanes to have ever flown. Show us your setup, show us your work and show us your data. Okay, how's this for a productive topic: How do you propose we offer a means by which an OBAM aircraft community a means for installing an internally regulated alternator such that its operation transparent to the paradigm under which generators and alternators have been operated on aircraft since day-one to wit: (1) Absolute pilot control over engine drive power source. (2) Failure and hazard free switching of the engine driven power source at any time and under any conditions. . . . of course, answers to the above will offer the OBAM aircraft builder a means by which any attractive OV protection philosophy can be added assuming he/she so desires. These are the questions I thought you were going to answer when you went off to do the tests over a year ago. Presumably you have the data necessary to make considered recommendations. We're all ears. Bob . . . ________________________________ Message 13 ____________________________________ Time: 09:44:58 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: magneto timing buzz box --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 07:30 PM 9/17/2005 -0400, you wrote: >--> AeroElectric-List message posted by: "Greg Campbell" > > >Take a look at the $25 kit from www.MagnetoTimer.com >and see if that meets your needs. > >I've built two - it's a fun little soldering project, all the parts >are included and identified (taped to the instruction sheet). >About an hour of fitting & soldering and you've got a nice tool. > >The leads coil up and stow inside the open front of the plastic case. > >Greg If you have done two of them, I presume they work as advertised. This looks like one hell-of-a bargain. He must be selling a bunch to get his costs down at this selling price. This looks like the most elegant alternative to the AC impedance measuring device. Ron's approach with a milliohm-sensitive ohmmeter is an elegant, non-specialized approach in the DC measurement world too. Bob . . . ________________________________ Message 14 ____________________________________ Time: 10:44:46 PM PST US From: rv-9a-online Subject: Re: AeroElectric-List: FW: Splice 6AWG Wire --> AeroElectric-List message posted by: rv-9a-online Pete, I would crimp a ring terminal on both ends and secure with a bolt. Wrap the whole thing up with silicone fusion tape. It will look like a pig in a python, but it should work. If you want it to be more secure, mount a similiar type splice to a UMHW block that is counterbored for the bolt, and mount the UMHW block with screws to the structure somewhere. If you don't have any UMHW, try any kind of rigid plastic or plexiglass. If you want to spend money, you can use a barrier terminal. Google "6 awg barrier terminal" and poke around the internet. Vern Little Pete Howell wrote: >--> AeroElectric-List message posted by: "Pete Howell" > > >I have one of the in-line maxifuse holders wirth 6AWG wire. One lead is not >long enough. How is the best way to splice in a longer piece of 6AWG? > > > >