---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 09/04/04: 8 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 09:31 AM - (david caswell) 2. 09:39 AM - (david caswell) 3. 09:59 AM - current limiting warning lights for EI instruments (Brian Lloyd) 4. 03:16 PM - Re: current limiting warning lights for EI instruments (david caswell) 5. 04:01 PM - Z-13 modifications for 35 amp PM Alternator (David Carter) 6. 04:56 PM - Re: current limiting warning lights for EI instruments (Brian Lloyd) 7. 06:19 PM - Cleveland Crimp Tool Mystery Solved .NOT . (Robert L. Nuckolls, III) 8. 09:51 PM - Pitot Heat wiring question.... (jacklockamy) ________________________________ Message 1 _____________________________________ Time: 09:31:10 AM PST US From: david caswell 1.16 MISSING_SUBJECT Missing Subject": header@matronics.com --> AeroElectric-List message posted by: david caswell I am in process of installing International Electronics iInstruments and am connecting wiring to the panel mounted warning lights (B&C) from the instruments (EGT/CHT and Fuel). The installation instructions specify that current be no higher that 1/10 amp on the FUEL, and 2/10 amp on the EGT. The signal from both instruments creates a ground. What is the best way to limit the current from the buss to these lights? A resistor in series? And is the R=E/I the way to calculate the size of this resistor? (14/.020=700) ? 700 ohm resistor? I am also wiring a "starter engaged" warning light from the starter "I" terminal. Does this lead need a resistor before it gets to the warning light? Any help would be greatly appreciated. Thank you. David ________________________________ Message 2 _____________________________________ Time: 09:39:29 AM PST US From: david caswell 1.16 MISSING_SUBJECT Missing Subject": header@matronics.com --> AeroElectric-List message posted by: david caswell I am looking for a grip mounted "slide switch" for my flaps. The only one I've located is Otto Controls http://ottoeng.com/control/slideswitch.htm. The price is $180. I think I remember reading about one that was priced more reasonably. Does anyone have a source for this item? THANK YOU ________________________________ Message 3 _____________________________________ Time: 09:59:58 AM PST US From: Brian Lloyd Subject: AeroElectric-List: current limiting warning lights for EI instruments --> AeroElectric-List message posted by: Brian Lloyd > --> AeroElectric-List message posted by: david caswell > > > I am in process of installing International Electronics iInstruments > and am connecting wiring to the panel mounted warning lights (B&C) > from the instruments (EGT/CHT and Fuel). The installation > instructions specify that current be no higher that 1/10 amp on the > FUEL, and 2/10 amp on the EGT. The signal from both instruments > creates a ground. What is the best way to limit the current from the > buss to these lights? A resistor in series? Yes. > And is the R=E/I the way to calculate the size of this resistor? > (14/.020=700) ? 700 ohm resistor? You are correct in how you calculate the resistance but you neglected to account for the resistance in the bulb itself. You also didn't indicate whether you plan to use incandescent light indicators or LED indicators. Also, 2/10 amp is 0.2A, not 0.020A. The latter is 20mA, just about right for an LED. If the indicator is an incandescent bulb you just select the bulb to have the proper current draw. If it is a low-voltage bulb, perhaps 6.3V, then you need a dropping resistor in series to put the proper voltage drop across the bulb. Likewise for an LED. > I am also wiring a "starter engaged" warning light from the starter > "I" terminal. Does this lead need a resistor before it gets to the > warning light? It depends on the type of bulb you are using. Can you provide more detail? Brian Lloyd 6501 Red Hook Plaza brianl@lloyd.com Suite 201 +1.340.998.9447 St. Thomas, VI 00802 ________________________________ Message 4 _____________________________________ Time: 03:16:18 PM PST US From: david caswell Subject: Re: AeroElectric-List: current limiting warning lights for EI instruments --> AeroElectric-List message posted by: david caswell Brian Lloyd wrote: --> AeroElectric-List message posted by: Brian Lloyd > --> AeroElectric-List message posted by: david caswell > > > I am in process of installing International Electronics iInstruments > and am connecting wiring to the panel mounted warning lights (B&C) > from the instruments (EGT/CHT and Fuel). The installation > instructions specify that current be no higher that 1/10 amp on the > FUEL, and 2/10 amp on the EGT. The signal from both instruments > creates a ground. What is the best way to limit the current from the > buss to these lights? A resistor in series? Yes. > And is the R=E/I the way to calculate the size of this resistor? > (14/.020=700) ? 700 ohm resistor? You are correct in how you calculate the resistance but you neglected to account for the resistance in the bulb itself. You also didn't indicate whether you plan to use incandescent light indicators or LED indicators. Also, 2/10 amp is 0.2A, not 0.020A. The latter is 20mA, just about right for an LED. If the indicator is an incandescent bulb you just select the bulb to have the proper current draw. If it is a low-voltage bulb, perhaps 6.3V, then you need a dropping resistor in series to put the proper voltage drop across the bulb. Likewise for an LED. > I am also wiring a "starter engaged" warning light from the starter > "I" terminal. Does this lead need a resistor before it gets to the > warning light? It depends on the type of bulb you are using. Can you provide more detail? The warning lights are from the B & C Specialties http://www.bandc.biz/cgi-bin/ez-catalog/cat_display.cgi?10X358218#s888-1-2. I really didn't look at the bulbs, or even if they had bulbs. I assume they are incandescent. I will look tomorrow. Thanks for direction. Brian Lloyd 6501 Red Hook Plaza brianl@lloyd.com Suite 201 +1.340.998.9447 St. Thomas, VI 00802 ________________________________ Message 5 _____________________________________ Time: 04:01:39 PM PST US From: "David Carter" Subject: AeroElectric-List: Z-13 modifications for 35 amp PM Alternator --> AeroElectric-List message posted by: "David Carter" After the recent exchange of ideas on "simplification", and an examination of relays and contactors available for use to shutdown the PM alternator, and because of a concern expressed by one fellow of a short in the voltage regulator and nothing between the alternator and the VR to protect the wires or the VR, here are two things I think I need to do to in adapting Z-13 to my specific system: 1. Relay to connect/disconnect the alternator & VR from the aircraft electrical busses (as shown in ORIGINAL - unmodified - Z-13, not the stuff I put on my website the other night): - Since the SD-8 (8 amp device) is being replaced with a 35 amp John Deere PM alternator as my only alternator, the S-704-1 relay, being good for only 20 amps continuous, will be replaced by, for example, a Bosch High Capacity (50 amps) relay, WayTek p/n 75002, Bosch p/n 0 332 019 110, 12v, SPST, 50 amps Normally Open, four terminals (2 for coil, 2 for power) , bracket mount $3.53 + $0.27 for 75281 connector shell (vs $10 for S-704-1 from B and C). - Does it look like I have a reasonable amount of "head room" (if that is the correct term) for the relay, it being rated at 50 amps (DC) and my alternator being rated at 35 amps ( but putting out who-knows-what into the regulator, which has to suck up and dissipate all the unused electrons)? 2. Protect the wires between "dynamo" and VR with in-line fuses of ______ amp capacity: - Since the "dynamo" is putting out unregulated voltage and alternating current which is directly proportional to rpm of alternator, and independent of what my aircraft systems (other than the VR) are consuming, and given that the alternator is "rated at" 35 amps and I won't have any more than that "on-line" at any time, then how do I design appropriate protection for the 2 wires going to the VR? - What is the nature of the current flow in the 2 wires when the airplane is actually consuming 35 amps? . . . -- I.e., at a given engine and alternator rpm at cruise, and actual electrical consumption by stuff in the airplane actually turned on and consuming 35 amps of electricity, what kind and rating of fuse do I need in each of the 2 wires between the alternator and VR? 17.5 amps in each wire, or 35 amps in each wire? ... -- Whichever, then how much "head room" should I allow for, i.e., if each wire is going to be designed for a normal current of 35 amps, then revised Fig 8-4 says I might consider, for 35 deg C/63 deg F rise, using "13.5 awg" (pick next larger, 12 awg, which is what Z-13 shows for use with the 8 amp dynamo). If max current is only 17.5 amps, then could use 18 or 16 awg for 35 deg C rise. Z-13 shows using 12 awg. ...-- If want to allow only a 10 deg C rise (18 deg F) in the already warm engine compartment, then Fig 8-4 suggests 8 awg for 35 amps each wire or 14 awg for 17.5 amps in each wire. - The bigger question - peculiar to PM alternators (dynamos) - is this: If alternator output is proportional to rpm, only, not to what the aircraft (other than the VR) is consuming, it looks like 1) I need a graph (or need to make my own) of "current vs rpm" and 2) if I size my pulleys for the alternator so I get enough current to run my "night IFR, descent to landing phase of flight" load at some reduced descent power, then when I am cruising at higher rpm, or taking off and climbing (or racing?) at full throttle, then what is the current output of the PM alternator? Whatever I'm not consuming out of the VR is going to be consumed by the VR itself to generate heat - correct? If so, then I need to size my wires from alternator to VR and fuse them to protect against my "max engine/alternator rpm" condition. I don't yet know what that is. How can I estimate it? Looks like I need an AC ammeter in my aircraft so I'll know what the alternator is doing. Is there such a device available to adapt to my OBAM aircraft? I assume it will be different from the DC loadmeters and ammeters we normally discuss on this list. David ________________________________ Message 6 _____________________________________ Time: 04:56:00 PM PST US From: Brian Lloyd Subject: Re: AeroElectric-List: current limiting warning lights for EI instruments --> AeroElectric-List message posted by: Brian Lloyd > --> AeroElectric-List message posted by: david caswell > > > The warning lights are from the B & C Specialties > http://www.bandc.biz/cgi-bin/ez-catalog/cat_display.cgi? > 10X358218#s888-1-2. I really didn't look at the bulbs, or even if > they had bulbs. I assume they are incandescent. I will look > tomorrow. Thanks for direction. I am familiar with the assembly as the same one came with my LR-3 regulator. I don't remember the current drain either but I suspect it would work fine directly with the EI instruments without any extra hardware. Brian Lloyd 6501 Red Hook Plaza brianl@lloyd.com Suite 201 +1.340.998.9447 St. Thomas, VI 00802 ________________________________ Message 7 _____________________________________ Time: 06:19:51 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Cleveland Crimp Tool Mystery Solved .NOT . --> AeroElectric-List message posted by: "Robert L. Nuckolls, III" At 06:58 AM 9/3/2004 -0700, you wrote: >--> AeroElectric-List message posted by: "Paul Messinger" > > >----- Original Message ----- >From: "Robert L. Nuckolls, III" >To: >Subject: AeroElectric-List: Re: Cleveland Crimp Tool Mystery Solved . . . > >snip>>Unlike the tools B&C sells with symmetrical dies, >>>> > >Bob, I simply do not understand how the above symetrical die tool will >properly crimp a terminal. > >Sure it can crimp the conductor to the needed gas tight crimp. > >However the insulation grip REQUIRES a different shape die to properly crimp >the insulation with the metal sleeve that is a part of the PIDG terminal. >The need is to crimp the sleeve on both sides of the wire with minimal >crimping on top of the wire. > >After this thread started I went and looked again at my various crimpers. I >have crimpers designed for the vinyl insulation terminals commonly sold in >auto stores as well as AMP crimpers designed for PIDG terminals. Both types >work well on the terminals they were designed for. ALL have different die >shapes for the two parts of the crimp. > >Insulation support is part of the terminal design and a proper insulation >crimp is needed in my opinion (as well as the industry it seems). Simply >looking at the result of a proper crimp shows the inner metal sleeve of the >terminal nicely shaped around the wire insulation without insulation >distortion and nearly 360 degree support. The excess material results in a >end view much like a round fush acft with mid stubby wings =O=. > >Proper insulation support on the wire side of the crimp is critical to wire >to terminal long term resistance to failure. I was skeptical too when I evaluated the sample of the low-cost tool that lunched my parts/tools business a few years ago. Up to that time, I'd used nothing but the $high$ professional tools from AMP and installed the occasional terminal with the hardware store, stamped sheet metal tools. Crimps produced by the $40 tool were, as you've noted, decidedly different that the "pro" tools. See: http://www.aeroelectric.com/articles/CrimpTools/H.jpg This picture shows a 22-18 PIDG closed down on a 22AWG Tefzel wire (22759/16-22) with the "pro" tool and the "el-cheapo" tool. Yup, the one on the right is more purty . . . but is it all that different in performance? If we're trying to relieve stress on the transition from stranded to solid conductors at the crimp, all that's required is some support of the wire. As it was explained to me some years ago, support means anything from just shy of actually touching the insulation (meaning that a couple thousanths gap is not evil) to actually putting some crush on the insulation. Recall that we're crushing the bejabbers out of the stands to get gas tight conduction - there's no prohibition for putting some crush on the insulation in the support grip as well. The symmetrical die tool puts considerable mash on an 18AWG insulation in the red PIDG terminal. While the well-molded insulation grip produced by the $high$ is pleasing to look at, there's no foundation in physics that says it outperforms its ugly cousins. The wire grip produced by the Cleveland tool in http://www.aeroelectric.com/Pictures/CLEVELAND66A.jpg just barely contacts the insulation . . . since this is the smallest PVC wire that would be used with that terminal, I'll suggest the insulation grip will be adequate for 22-18 AWG PVC. On the other hand, the grip shown in http://www.aeroelectric.com/Pictures/CLEVELAND65A.jpg is WAAAaaayyyy too loose. Dave tells us that a replacement for this tool measures about 0.010" smaller in the wire grip opening . . . given the breezeway I observe in the picture above, I am skeptical that 0.010" more closure on the die will close sufficiently on 22769/16-22 Tefzel. If I had my druthers, everyone building their own airplane would have AMP tools to install AMP terminals throughout. However, that's not possible so our goal as advisors is to gage the impact of various compromises. I judge that the Cleveland tool I tested is NOT a compromise but completely off the mark for installing PIDG on 22759/16 wire. However, the $low$, symmetrical die tool as tested several years ago produces consistent, and adequate if somewhat ugly crimps that will perform well. Just for grins, I went to the bench and put a red PIDG on Tefzel wire with a hardware store crimp tool. This tool produced the predictably funky results illustrated in http://www.aeroelectric.com/Pictures/90.jpg and http://www.aeroelectric.com/Pictures/92.jpg Ugly? Yes. Cross section through the wire grip? Gas tight. Pull test? Over 30 pounds . . . wire failed leaving strands captured in wire grip of terminal. Insulation grip? Again, not very pretty but I see no reason in physics to suspect it's any less adequate to the task than other tools I have ranging from $40 to $600. Bob . . . --- ________________________________ Message 8 _____________________________________ Time: 09:51:56 PM PST US From: "jacklockamy" Subject: AeroElectric-List: Pitot Heat wiring question.... --> AeroElectric-List message posted by: "jacklockamy" Here's one that has me 'stumped'...... Building an RV-7A. Wings are on... I'm at the airport wiring the wings/wingtips. I hook up the Pitot (Gretz) Heat wire, turn ON the battery side of the Cessna type Split Master switch I have installed... no heat. Check to make sure I'm getting 12v to the pitot mast +wiring... yep. Then I turn the ALTERNATOR side of the split master ON in conjunction with the Battery side of the switch... then I get heat at the Pitot mast. And when I say "heat".. I mean "HEAT!!!". My Gretz heated pitot tube gets so hot it will burn you if you aren't careful. What is going on here? I have a master bus (where the pitot + is connected) in addition to an Avionics bus. Everthing else is working 'normally'..... Just can't figure out why the pitot mast doesn't get hot until the Alternator side of the split master is turned ON with the Battery side turned ON. All other items on the Master bus get "hot' when I turn the battery side of the split switch ON. Does this make sense? Why doesn't the mast get hot with just the Battery side of the switch on? I don't have an engine mounted (still at the re-builders) thus I have no alternator hooked up either....... It works, but I just don't understand what is going on.... Thanks in advance, Jack Lockamy Camarillo, CA BTW.... I was lucky enough to purchase my chromed Gretz heated Pitot tube, mounting bracket, etc. for $50! Another fellow was parting out his RV and I snagged it!