---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Wed 04/25/07: 12 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 02:58 AM - TR 3000 (RV_10) 2. 03:09 AM - Re: PM ALTERNATOR- REGULATOR CHOICE (Peter Harris) 3. 06:09 AM - Re: Re: DIY Intercom System (Robert L. Nuckolls, III) 4. 06:26 AM - Re: Clamp On DC Multimeters... (Robert L. Nuckolls, III) 5. 07:30 AM - Re: DIY Intercom System (az_gila) 6. 08:20 AM - Re: Easy question? (RV Builder (Michael Sausen)) 7. 11:49 AM - Mag Wiring (Jim Piavis) 8. 05:25 PM - Re: Re: DIY Intercom System (Robert L. Nuckolls, III) 9. 05:33 PM - Re: Mag Wiring (Robert L. Nuckolls, III) 10. 05:44 PM - REGULATOR CHOICE FOR SELF EXCITATION (Peter Harris) 11. 06:57 PM - Re: PM ALTERNATOR- REGULATOR CHOICE (Ken) 12. 08:47 PM - Re: PM ALTERNATOR- REGULATOR CHOICE (Peter Harris) ________________________________ Message 1 _____________________________________ Time: 02:58:55 AM PST US From: "RV_10" Subject: AeroElectric-List: TR 3000 Guys, We are looking at installing a FreeFlight TR 300 Radar Altimeter in our RV 10. Unfortunately the TR 300 needs 27.5 volts, and we are building a 12 volt ship. Is there any way to sensibly run this 27.5 volt item on our 12 volt ship? Thank you, John Cleary ________________________________ Message 2 _____________________________________ Time: 03:09:20 AM PST US From: "Peter Harris" Subject: RE: AeroElectric-List: PM ALTERNATOR- REGULATOR CHOICE Ken, I will need about 4A to run the EFI. Ignition is dual by one magneto and one electronic ignition module . It will be OK by me if I can cover the EFI only. But how much current would stall the alternator and stop the engine? Peter -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Ken Sent: Tuesday, 24 April 2007 10:41 PM Subject: Re: AeroElectric-List: PM ALTERNATOR- REGULATOR CHOICE To his credit, Peter has been asking lots of questions and I was trying to understand whether it was worth his effort to change parts and insure self excitation. For my Z-14 system, it doesn't matter to me whether either alternator will self excite. If I don't like how the engine is running, my procedure is to just switch to the second EFI system, which runs on the other battery and alternator. Self excitation is fine but I would encourage a bit of testing before counting on continued operation without a battery. Especially with a regulator that was not designed to perform without a battery. Now that Peter's has described what he is trying to do, I agree that self excitation or a second battery is essential for him. However self excitation might not help much if someone inadvertantly stalled the alternator and had a geared prop that promptly stopped turning. Self excitation might not be as comforting if Peter's EFI Jabiru doesn't windmill fast enough to restart his engine. For example he might want to insure that with his system it is not possible to inadvertantly (out of habit) turn on something like a landing light and stall the alternator... His "dual" power source should probably be strictly for feeding the engine. My PM alternator doesn't put out much current at idle rpm. Ken Robert L. Nuckolls, III wrote: > > > At 08:52 AM 4/23/2007 -0400, you wrote: > >> >> Peter >> >> I'm not sure why you want a regulator that will start up without a >> battery? It sounds like you do have a battery present. Do you know >> for sure that your regulator will not start without a battery present? > > > Why would one NOT want an alternator that will run > without a battery. Generators did this from day-one > and we had to give that feature up when generators got > replaced by alternators in the 60's. > > Alternators on the Bonanza and Barons have self excited > for decades and the company touts this as a desirable > feature. A few months ago we did an exercise to figure > out how to make an SD-8 come up without assistance from > a battery. > > This is generally considered a good thing to do and it > can be done. > > Bob . . . ________________________________ Message 3 _____________________________________ Time: 06:09:57 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: DIY Intercom System At 09:30 PM 4/24/2007 -0700, you wrote: > >Bob... if I wanted to switch sources on and off, would a switched short to >ground between the input resistor and capacitor for a single input work? > >Such as shorting the junction of R104 and C112 to ground (page 1.8.1 >schematic) > >gil A Yes. Bob . . . ---------------------------------------- ( IF one aspires to be "world class", ) ( what ever you do must be exercised ) ( EVERY day . . . ) ( R. L. Nuckolls III ) ---------------------------------------- ________________________________ Message 4 _____________________________________ Time: 06:26:35 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Clamp On DC Multimeters... At 07:08 PM 4/20/2007 +0000, you wrote: >Your first clue is that it is expensive...that tells you its about what >you should pay. > >But answer me this...Why on Earth would you want to spend that kind of >money?...HArbor freights $2.50 multimeter has a 10A shunt (namely will >measure up to 10 amps) . This should be adequate for 1/100th of the cost. > >Incidently the HF multimeter is very accurate...at least mine is. > >Frank The snap on ammeter permits a quick-n-convenient look at the current in a wire (or multiples of wires) without breaking into them. It's true that the least expensive of multimeters is more accurate for a small fraction of what it cost us for the basic multimeter of 40 years ago. But one can still go more dollars for features and robustness. I spent about $60 a few years back to acquire a multimeter that reads capacitors. I already had a dozen such instruments in various tool boxes but I had a task that required the matching of some capacitors. I needed the feature, bought the instrument and finished the task. I don't think I've needed that feature again since but the critter is there . . . if I need it again. I found a 400A snap-on Fluke adapter for multimeters on Ebay a few months ago. Got it for about 2/3 the cost of new. I've already used it to ease the $time$ to do several tasks. I've replaced the banana plugs with a BNC connector on it so that I can go to my 'scope. I've got a bunch of BNC to dual banana adapters so I can still stick the critter onto a multimeter for single value measurements. I've got a job coming up at work where I'll use my 'scope and the DC snap on ammeter to get some sense of the dynamics in a current path on an airplane. The short answer is that one tailors a purchase to present and future needs. I buy $3 multimeters at HF by the dozens to give away at my seminars. "Who in this room does NOT yet own a multimeter?" Everybody leaves my seminars owning at least one multimeter. But if the $3 feller lacks a feature or general robustness/reliability, then one digs deeper into the pockets. I don't pack a $3 HF meter to go on a troubleshooting trip. The 20 year-old Fluke is my travel companion. Bob . . . ---------------------------------------- ( IF one aspires to be "world class", ) ( what ever you do must be exercised ) ( EVERY day . . . ) ( R. L. Nuckolls III ) ---------------------------------------- ________________________________ Message 5 _____________________________________ Time: 07:30:24 AM PST US Subject: AeroElectric-List: Re: DIY Intercom System From: "az_gila" Thanks Bob... I presume a short (less than 6 inches) twisted pair to a panel switch would do the job... gil A Read this topic online here: http://forums.matronics.com/viewtopic.php?p=109167#109167 ________________________________ Message 6 _____________________________________ Time: 08:20:10 AM PST US From: "RV Builder (Michael Sausen)" Subject: RE: AeroElectric-List: Easy question? See, I knew it was easy. I completely forgot about the drop from a diode. Thanks! Do not archive -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Ernest Christley Sent: Tuesday, April 24, 2007 10:22 PM Subject: Re: AeroElectric-List: Easy question? RV Builder (Michael Sausen) wrote: > > I have a device that lives quite happily between around 11vdc to around 13.9vdc and then promptly stops working above that number. Problem is most charging systems are above 14vdc. It uses milliamps at best so I'm looking for the easiest way to drop a volt. > > A couple of diodes in series will give you between 1 and 1.5 volt drop. ________________________________ Message 7 _____________________________________ Time: 11:49:04 AM PST US From: Jim Piavis Subject: AeroElectric-List: Mag Wiring I didn't get any verification on this so I thought I'd throw this out again ... I'm sure this has been discussed but searching the archives didn't produce a lot, so I wanted to request a clarification. I'm wiring up two Slick mags with SPST switches. From the Z-13 diagram here 's how I understand the mag wiring: 1) Use 18AWG shielded wire 2) Connect the mag-side ground pigtail to the ground stud on the mag. 3) For switch side, connect the ground pigtail to the ground side of t he switch, thus when the switch is closed, the mag grounds to the engine vi a the mag, using the shielding for the ground path and negating a parallel ground path. Do I have this correct? Thanks, Jim RV-7 Wiring ________________________________ Message 8 _____________________________________ Time: 05:25:50 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: DIY Intercom System At 07:28 AM 4/25/2007 -0700, you wrote: > >Thanks Bob... > >I presume a short (less than 6 inches) twisted pair to a panel switch >would do the job... > >gil A Sure. Bob . . . ________________________________ Message 9 _____________________________________ Time: 05:33:34 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Mag Wiring At 11:47 AM 4/25/2007 -0700, you wrote: >I didn t get any verification on this so I thought I d throw this out again& > >I'm sure this has been discussed but searching the archives didn't produce >a lot, so I wanted to request a clarification. > >I'm wiring up two Slick mags with SPST switches. From the Z-13 diagram >here's how I understand the mag wiring: > > >1) Use 18AWG shielded wire 22 works . . . most folks have lower limits for sizes of wires that run to the engine. It's a mechanical robustness thing. 20AWG would be a fine if you have it already. >2) Connect the mag-side ground pigtail to the ground stud on the mag. Yes . . . >3) For switch side, connect the ground pigtail to the ground side of t >he switch, thus when the switch is closed, the mag grounds to the engine via >the mag, using the shielding for the ground path and negating a parallel >ground path. > >Do I have this correct? You've read the schematic correctly and this is what's recommended. Bob . . . ________________________________ Message 10 ____________________________________ Time: 05:44:11 PM PST US From: "Peter Harris" Subject: AeroElectric-List: REGULATOR CHOICE FOR SELF EXCITATION Bob in your Z-25 were you able to self excite using the simple B&C solid state regulator or did you use another type of regulator? If yes what is the brand? Thanks, Peter -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Thursday, 26 April 2007 11:33 AM Subject: Re: AeroElectric-List: Mag Wiring At 11:47 AM 4/25/2007 -0700, you wrote: >I didn t get any verification on this so I thought I d throw this out again& > >I'm sure this has been discussed but searching the archives didn't produce >a lot, so I wanted to request a clarification. > >I'm wiring up two Slick mags with SPST switches. From the Z-13 diagram >here's how I understand the mag wiring: > > >1) Use 18AWG shielded wire 22 works . . . most folks have lower limits for sizes of wires that run to the engine. It's a mechanical robustness thing. 20AWG would be a fine if you have it already. >2) Connect the mag-side ground pigtail to the ground stud on the mag. Yes . . . >3) For switch side, connect the ground pigtail to the ground side of t >he switch, thus when the switch is closed, the mag grounds to the engine via >the mag, using the shielding for the ground path and negating a parallel >ground path. > >Do I have this correct? You've read the schematic correctly and this is what's recommended. Bob . . . ________________________________ Message 11 ____________________________________ Time: 06:57:50 PM PST US From: Ken Subject: Re: AeroElectric-List: PM ALTERNATOR- REGULATOR CHOICE Peter Stall is perhaps not the best term for me to have used. I would think that the best plan then would be that your alternator should be able to supply at least 4 amps at idle in case you pull power back to idle. What you want to avoid is any possible combination of rpm and electrical load that could pull the voltage below what your EFI system needs to keep running. Many automotive systems will run down to about 8 volts or they would not be able to start the car with a weak battery. They typically lengthen the injection pulse at low voltage to compensate for more sluggish injector operation. I don't know how many amps the Jabiru alternator will put out at idle but I'd guess that your plan will work if the alternator is only powering the EFI. Definitely worth a try I think! If it doesn't work you can always try adding a small battery. There have been some interesting alternatives used over the years such as gravity fed fuel to a port or nozzle that can meter enough fuel in to keep you airborne. One then used the throttle as a mixture control. Similarly there have been cases where someone made it to the airport with the priming pump after their carburetor quit supplying fuel. I've also heard that such schemes often caused more troubles than they saved ;( Ken Peter Harris wrote: > >Ken, >I will need about 4A to run the EFI. Ignition is dual by one magneto and one >electronic ignition module . It will be OK by me if I can cover the EFI >only. But how much current would stall the alternator and stop the engine? >Peter > > ________________________________ Message 12 ____________________________________ Time: 08:47:54 PM PST US From: "Peter Harris" Subject: RE: AeroElectric-List: PM ALTERNATOR- REGULATOR CHOICE Thanks Ken. I was thinking of using a carb as the throttle body but have since inspected the Aerocarb and found it unsuitable. There are other possibilities, I am still cooking but most result in a compromise of some kind. Thanks for the input. Peter -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Ken Sent: Thursday, 26 April 2007 11:53 AM Subject: Re: AeroElectric-List: PM ALTERNATOR- REGULATOR CHOICE Peter Stall is perhaps not the best term for me to have used. I would think that the best plan then would be that your alternator should be able to supply at least 4 amps at idle in case you pull power back to idle. What you want to avoid is any possible combination of rpm and electrical load that could pull the voltage below what your EFI system needs to keep running. Many automotive systems will run down to about 8 volts or they would not be able to start the car with a weak battery. They typically lengthen the injection pulse at low voltage to compensate for more sluggish injector operation. I don't know how many amps the Jabiru alternator will put out at idle but I'd guess that your plan will work if the alternator is only powering the EFI. Definitely worth a try I think! If it doesn't work you can always try adding a small battery. There have been some interesting alternatives used over the years such as gravity fed fuel to a port or nozzle that can meter enough fuel in to keep you airborne. One then used the throttle as a mixture control. Similarly there have been cases where someone made it to the airport with the priming pump after their carburetor quit supplying fuel. I've also heard that such schemes often caused more troubles than they saved ;( Ken Peter Harris wrote: > >Ken, >I will need about 4A to run the EFI. Ignition is dual by one magneto and one >electronic ignition module . It will be OK by me if I can cover the EFI >only. But how much current would stall the alternator and stop the engine? >Peter > > ------------------------------------------------------------------------------------- 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.