---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 06/18/07: 11 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:10 AM - Re: Regulator trouble? (Robert L. Nuckolls, III) 2. 07:11 AM - Re: Antenna doubler plate - prime or not (Robert L. Nuckolls, III) 3. 08:41 AM - Re: Regulator trouble? (Matt Prather) 4. 09:25 AM - Re: Regulator trouble? (Ken) 5. 10:28 AM - Re: Rear-Battery version of Z-19 (n707sm) 6. 06:24 PM - Re: Regulator trouble? (Robert L. Nuckolls, III) 7. 06:47 PM - Re: Regulator trouble? (Alan Adamson) 8. 06:49 PM - Re: Regulator trouble? (Alan Adamson) 9. 06:54 PM - RTV sealants (bob mackey) 10. 07:14 PM - Re: Re: Rear-Battery version of Z-19 (Robert L. Nuckolls, III) 11. 08:17 PM - Re: Regulator trouble? (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 07:10:44 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Regulator trouble? At 07:09 PM 6/17/2007 -0800, you wrote: > >I've got more info now, but I'm not sure what it means. I wired up a jack >as per Bob's suggestion and can read field voltage on the VOM in flight. I >also changed the setpoint on the regulator by about 1 turn on the >adjustment screw. The downloaded installation instructions said that >should be about 2 tenths of a volt. It had been running about 14.6. The >regulator turns out to be an LR3B-14 not the C model I reported >previously. I don't know how much difference that makes. > >When started, the voltage ran right at 14.4, exactly as expected after the >adjustment. The field was about 3.5 to 4.5 volts at idle. I'm using a >digital VOM because it's what I have, so it jumps around a bit. With >strobe, landing/taxi and position lights on and at idle, the buss came >down to about 14.1 and the field rose to about 7 or 8 volts. Load was >around 17 amps by my meter. > >In flight the numbers were pretty similar except that the buss never fell >much below 14.4 no matter what I did with the lights. The field ran >somewhere in the 4ish range with no lights and around 8 with. After about >30 minutes of flying, the buss was at 14.5. When I taxied in, it was 14.7 >at idle which I don't understand at all. The field breaker did not blow today. > >I'm in watch and wait mode for now. Excellent data! . . . and pretty much as expected. Let's review the significance: First, there are no differences between the B & C revisions of this regulator that would affect the phenomenon under investigation. (1) "With strobe, landing/taxi and position lights on and at idle, the buss came down to about 14.1 and the field rose to about 7 or 8 volts." (a) The maximum possible range for field voltages is 0 to bus voltage . . . or a little below bus voltage because the pass transistor doesn't turn on with zero-volt drop. We would NEVER expect to see field voltage at ZERO during any set of normal operating conditions . . . ZERO field is ZERO output. The only time we would expect to see zero output is if something was broke. (b) The slight drop with load is within expectations. (c) The field voltage reading of 7-8 volts at idle tells us that your alternator's output is about half used up for this RPM and load conditions. As we noted above, the field cannot rise to more than about 14 volts and under the test conditions cited, you were already half way there. (2) "Load was around 17 amps by my meter." (a) Is this an alternator loadmeter? In other words, the 17A reading is the alternator output current for the conditions cited? (3) "In flight the numbers were pretty similar except that the buss never fell much below 14.4 no matter what I did with the lights." (a) Every regulator designer is pleased to hear this. The goal is to craft electronics that maintains the bus at the established set-point irrespective of load. So, for field voltages greater than zero and less than bus voltage, we would expect the bus voltage to stay put under any load that does not cause the field voltage to max out. (4) "The field ran somewhere in the 4ish range with no lights and around 8 with." (a) What size alternator is this? I think you mentioned a 35A machine? Again, the reading of about 8 volts with loads on (and assuming the same 17A of output) that the alternator's output is about 1/2 used up. If this were my research project, I'd throw a little 200 samples per second data acquisition system (Snipe trap) on the field, bus volts and bus amps. Then I'd go fly the airplane and attempt to induce a trip by manipulation of controls for electrical system loads. Okay, your snipe catching sack is in hand and your flashlight (field volts indicator) is charged up. What we would hope to capture is what the field voltage is doing just prior and/or during a trip event. On the next flight, you'll want to "fiddle with the switches and things" while observing field voltage and see if you can induce a trip. The readings you've cited are strong indications that the system is/was performing as-designed during the period of your observations. Bob . . . ________________________________ Message 2 _____________________________________ Time: 07:11:08 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Antenna doubler plate - prime or not My personal preference is to have NO RTV exposed in the final installation. All sealing should occur in the protected environment between two relatively flat and tightly clamped surfaces. After the bolts are torqued, wipe away all excess RTV that might ooze out from between the antenna and ship's skin. Bob . . . >You might consider using a paintable sealant rather than RTV. > >Regards, > >Greg Young > > > > > I didn't like the way the cork gasket looked anyway......RTV rocks! > > > > Thanks Bob! > > > > Ralph > > > > >-- >8:23 AM > > >incoming mail is certified Virus Free. >Checked by AVG. Bob . . . ---------------------------------------- ( "Physics is like sex: sure, it may ) ( give some practical results, but ) ( that's not why we do it." ) ( ) ( Richard P. Feynman ) ---------------------------------------- ________________________________ Message 3 _____________________________________ Time: 08:41:01 AM PST US Subject: Re: AeroElectric-List: Regulator trouble? From: "Matt Prather" If trying to induce a trip, maybe it would make sense to run the test early in the morning when the OAT is low so as to help the alternator put out maximum snort? Does this regulator bump the voltage set point in response to low temperature (temperature compensated)? Regards, Matt- > > > At 07:09 PM 6/17/2007 -0800, you wrote: > >> >>I've got more info now, but I'm not sure what it means. I wired up a jack >>as per Bob's suggestion and can read field voltage on the VOM in flight. >> I >>also changed the setpoint on the regulator by about 1 turn on the >>adjustment screw. The downloaded installation instructions said that >>should be about 2 tenths of a volt. It had been running about 14.6. The >>regulator turns out to be an LR3B-14 not the C model I reported >>previously. I don't know how much difference that makes. >> >>When started, the voltage ran right at 14.4, exactly as expected after >> the >>adjustment. The field was about 3.5 to 4.5 volts at idle. I'm using a >>digital VOM because it's what I have, so it jumps around a bit. With >>strobe, landing/taxi and position lights on and at idle, the buss came >>down to about 14.1 and the field rose to about 7 or 8 volts. Load was >>around 17 amps by my meter. >> >>In flight the numbers were pretty similar except that the buss never fell >>much below 14.4 no matter what I did with the lights. The field ran >>somewhere in the 4ish range with no lights and around 8 with. After about >>30 minutes of flying, the buss was at 14.5. When I taxied in, it was 14.7 >>at idle which I don't understand at all. The field breaker did not blow >> today. >> >>I'm in watch and wait mode for now. > > > Excellent data! . . . and pretty much as expected. Let's review > the significance: > > First, there are no differences between the B & C revisions of this > regulator that would affect the phenomenon under investigation. > > (1) "With strobe, landing/taxi and position lights on and at idle, > the buss came down to about 14.1 and the field rose to about > 7 or 8 volts." > > (a) The maximum possible range for field voltages is 0 to bus > voltage . . . or a little below bus voltage because the > pass transistor doesn't turn on with zero-volt drop. We > would NEVER expect to see field voltage at ZERO during > any set of normal operating conditions . . . ZERO field > is ZERO output. The only time we would expect to see zero > output is if something was broke. > > (b) The slight drop with load is within expectations. > > (c) The field voltage reading of 7-8 volts at idle tells us > that your alternator's output is about half used up for > this RPM and load conditions. As we noted above, the field > cannot rise to more than about 14 volts and under the test > conditions cited, you were already half way there. > > (2) "Load was around 17 amps by my meter." > > (a) Is this an alternator loadmeter? In other words, the 17A > reading is the alternator output current for the conditions > cited? > > (3) "In flight the numbers were pretty similar except that the > buss never fell much below 14.4 no matter what I did with > the lights." > > (a) Every regulator designer is pleased to hear this. The > goal is to craft electronics that maintains the bus at the > established set-point irrespective of load. So, for field > voltages greater than zero and less than bus voltage, we would > expect the bus voltage to stay put under any load that does > not cause the field voltage to max out. > > (4) "The field ran somewhere in the 4ish range with no lights > and around 8 with." > > (a) What size alternator is this? I think you mentioned a > 35A machine? Again, the reading of about 8 volts with loads > on (and assuming the same 17A of output) that the alternator's > output is about 1/2 used up. > > If this were my research project, I'd throw a little 200 samples > per second data acquisition system (Snipe trap) on the field, bus > volts and bus amps. Then I'd go fly the airplane and attempt to > induce a trip by manipulation of controls for electrical system > loads. > > Okay, your snipe catching sack is in hand and your flashlight > (field volts indicator) is charged up. What we would hope to > capture is what the field voltage is doing just prior and/or > during a trip event. On the next flight, you'll want to "fiddle > with the switches and things" while observing field voltage and > see if you can induce a trip. > > The readings you've cited are strong indications that the system > is/was performing as-designed during the period of your observations. > > Bob . . . > > ________________________________ Message 4 _____________________________________ Time: 09:25:39 AM PST US From: Ken Subject: Re: AeroElectric-List: Regulator trouble? I have a slightly different take on this as it seems there might already be some clues here. Shouldn't the field voltage go above 8 volts when the alternator is loaded on the ground. If it is putting out less that 14.4 volts at low rpm - why isn't the field voltage up around 12 or 13? High resistance somewhere in the field? Next I'd want to know why 14.7 volts while taxiing in. Is the regulator voltage going up when it is hot? Does it not throttle back far enough under light load? Is there a connection that is high resistance when hot such that the regulator is sensing 14.4 but putting out 14.7 upstream where the voltmeter is located? Or is it an inaccurate voltmeter? If the connections have already been checked, I'd be tempted to temporarilly wire in a cheap regulator and see what happens. Ken Robert L. Nuckolls, III wrote: > > > At 07:09 PM 6/17/2007 -0800, you wrote: > >> >> I've got more info now, but I'm not sure what it means. I wired up a >> jack as per Bob's suggestion and can read field voltage on the VOM in >> flight. I also changed the setpoint on the regulator by about 1 turn >> on the adjustment screw. The downloaded installation instructions >> said that should be about 2 tenths of a volt. It had been running >> about 14.6. The regulator turns out to be an LR3B-14 not the C model >> I reported previously. I don't know how much difference that makes. >> >> When started, the voltage ran right at 14.4, exactly as expected >> after the adjustment. The field was about 3.5 to 4.5 volts at idle. >> I'm using a digital VOM because it's what I have, so it jumps around >> a bit. With strobe, landing/taxi and position lights on and at idle, >> the buss came down to about 14.1 and the field rose to about 7 or 8 >> volts. Load was around 17 amps by my meter. >> >> In flight the numbers were pretty similar except that the buss never >> fell much below 14.4 no matter what I did with the lights. The field >> ran somewhere in the 4ish range with no lights and around 8 with. >> After about 30 minutes of flying, the buss was at 14.5. When I taxied >> in, it was 14.7 at idle which I don't understand at all. The field >> breaker did not blow today. >> >> I'm in watch and wait mode for now. > > > Excellent data! . . . and pretty much as expected. Let's review > the significance: > > First, there are no differences between the B & C revisions of this > regulator that would affect the phenomenon under investigation. > > (1) "With strobe, landing/taxi and position lights on and at idle, > the buss came down to about 14.1 and the field rose to about > 7 or 8 volts." > > (a) The maximum possible range for field voltages is 0 to bus > voltage . . . or a little below bus voltage because the > pass transistor doesn't turn on with zero-volt drop. We > would NEVER expect to see field voltage at ZERO during > any set of normal operating conditions . . . ZERO field > is ZERO output. The only time we would expect to see zero > output is if something was broke. > > (b) The slight drop with load is within expectations. > > (c) The field voltage reading of 7-8 volts at idle tells us > that your alternator's output is about half used up for > this RPM and load conditions. As we noted above, the field > cannot rise to more than about 14 volts and under the test > conditions cited, you were already half way there. > > (2) "Load was around 17 amps by my meter." > > (a) Is this an alternator loadmeter? In other words, the 17A > reading is the alternator output current for the conditions > cited? > > (3) "In flight the numbers were pretty similar except that the > buss never fell much below 14.4 no matter what I did with > the lights." > > (a) Every regulator designer is pleased to hear this. The > goal is to craft electronics that maintains the bus at the > established set-point irrespective of load. So, for field > voltages greater than zero and less than bus voltage, we would > expect the bus voltage to stay put under any load that does > not cause the field voltage to max out. > > (4) "The field ran somewhere in the 4ish range with no lights > and around 8 with." > > (a) What size alternator is this? I think you mentioned a > 35A machine? Again, the reading of about 8 volts with loads > on (and assuming the same 17A of output) that the alternator's > output is about 1/2 used up. > > If this were my research project, I'd throw a little 200 samples > per second data acquisition system (Snipe trap) on the field, bus > volts and bus amps. Then I'd go fly the airplane and attempt to > induce a trip by manipulation of controls for electrical system > loads. > > Okay, your snipe catching sack is in hand and your flashlight > (field volts indicator) is charged up. What we would hope to > capture is what the field voltage is doing just prior and/or > during a trip event. On the next flight, you'll want to "fiddle > with the switches and things" while observing field voltage and > see if you can induce a trip. > > The readings you've cited are strong indications that the system > is/was performing as-designed during the period of your observations. > > Bob . . . > ________________________________ Message 5 _____________________________________ Time: 10:28:18 AM PST US Subject: AeroElectric-List: Re: Rear-Battery version of Z-19 From: "n707sm" Hi Bob, In Z-19/RB, it's called out to use 6" or less 12AWG between the Main and Engine Battery contactors and their respective busses. Without building a special mount for this, I could locate these busses close to the contactors but I would probably need about 15" of wire each. Would your suggestion be to go to 10AWG in this case? Thank you again :D Best Regards, Michael Read this topic online here: http://forums.matronics.com/viewtopic.php?p=119155#119155 ________________________________ Message 6 _____________________________________ Time: 06:24:19 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Regulator trouble? At 09:33 AM 6/18/2007 -0600, you wrote: > >If trying to induce a trip, maybe it would make sense to run the test >early in the morning when the OAT is low so as to help the alternator put >out maximum snort? Does this regulator bump the voltage set point in >response to low temperature (temperature compensated)? The regulator is not compensated for battery ambient. It is compensated for a close to zero temperature coefficient as practical. Ed also noted that the system tripped several times while in cruising flight so it seems a low-order probability that a first start of the day "cold test" would be any more revealing. Actually, given the numbers that Ed has cited, I'm pretty much convinced that "catching" his Snipe is going to be pretty tough with just a digital voltmeter. The best we might hope for is that the field voltage becomes jittery just before a nuisance trip when it had been stable earlier. Ed, you might consider getting an el-cheapo analog meter from Radio Shack. See: http://tinyurl.com/29yk5d This instrument has a 15 volt DC range that is ideal for this investigation. Right now, we're going to be more interested in dynamics (steady vs. twitchy) as opposed to knowing the actual reading. In the mean time, my software guru is looking into how hard it would be to do a quick turn on a little 4-channel, data acquisition system that would run off a laptop. Ed, do you have a laptop computer you could press into the service of Snipe Catching? Bob . . . ________________________________ Message 7 _____________________________________ Time: 06:47:23 PM PST US From: "Alan Adamson" Subject: RE: AeroElectric-List: Regulator trouble? Bob, not sure they get much cheaper than this http://www.dataq.com/products/startkit/di194rs.htm They also have them for USB, but not sure of the cost... Also 12Bit version are available. Alan -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Monday, June 18, 2007 10:23 PM Subject: Re: AeroElectric-List: Regulator trouble? --> At 09:33 AM 6/18/2007 -0600, you wrote: >--> > >If trying to induce a trip, maybe it would make sense to run the test >early in the morning when the OAT is low so as to help the alternator >put out maximum snort? Does this regulator bump the voltage set point >in response to low temperature (temperature compensated)? The regulator is not compensated for battery ambient. It is compensated for a close to zero temperature coefficient as practical. Ed also noted that the system tripped several times while in cruising flight so it seems a low-order probability that a first start of the day "cold test" would be any more revealing. Actually, given the numbers that Ed has cited, I'm pretty much convinced that "catching" his Snipe is going to be pretty tough with just a digital voltmeter. The best we might hope for is that the field voltage becomes jittery just before a nuisance trip when it had been stable earlier. Ed, you might consider getting an el-cheapo analog meter from Radio Shack. See: http://tinyurl.com/29yk5d This instrument has a 15 volt DC range that is ideal for this investigation. Right now, we're going to be more interested in dynamics (steady vs. twitchy) as opposed to knowing the actual reading. In the mean time, my software guru is looking into how hard it would be to do a quick turn on a little 4-channel, data acquisition system that would run off a laptop. Ed, do you have a laptop computer you could press into the service of Snipe Catching? Bob . . . ________________________________ Message 8 _____________________________________ Time: 06:49:46 PM PST US From: "Alan Adamson" Subject: RE: AeroElectric-List: Regulator trouble? Here's the USB 10 bit version http://www.dataq.com/products/startkit/di148.htm And the USB 12 bit version http://www.dataq.com/products/startkit/di158.htm Hope this helps... Still way cheaper than spending the time/effort to build one and write the software. Alan -----Original Message----- From: owner-aeroelectric-list-server@matronics.com [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L. Nuckolls, III Sent: Monday, June 18, 2007 10:23 PM Subject: Re: AeroElectric-List: Regulator trouble? --> At 09:33 AM 6/18/2007 -0600, you wrote: >--> > >If trying to induce a trip, maybe it would make sense to run the test >early in the morning when the OAT is low so as to help the alternator >put out maximum snort? Does this regulator bump the voltage set point >in response to low temperature (temperature compensated)? The regulator is not compensated for battery ambient. It is compensated for a close to zero temperature coefficient as practical. Ed also noted that the system tripped several times while in cruising flight so it seems a low-order probability that a first start of the day "cold test" would be any more revealing. Actually, given the numbers that Ed has cited, I'm pretty much convinced that "catching" his Snipe is going to be pretty tough with just a digital voltmeter. The best we might hope for is that the field voltage becomes jittery just before a nuisance trip when it had been stable earlier. Ed, you might consider getting an el-cheapo analog meter from Radio Shack. See: http://tinyurl.com/29yk5d This instrument has a 15 volt DC range that is ideal for this investigation. Right now, we're going to be more interested in dynamics (steady vs. twitchy) as opposed to knowing the actual reading. In the mean time, my software guru is looking into how hard it would be to do a quick turn on a little 4-channel, data acquisition system that would run off a laptop. Ed, do you have a laptop computer you could press into the service of Snipe Catching? Bob . . . ________________________________ Message 9 _____________________________________ Time: 06:54:01 PM PST US Subject: AeroElectric-List: RTV sealants From: "bob mackey" There were several recent recommendations for the use of RTV (room temperature vulcanizing) elastic sealants. Before putting this stuff near your airframe or avionics, you should know that there are many different types of RTV, and most of them are somewhat corrosive as a result of the acetic-acid curing chemistry (smells like vinegar). For mounting antennas to aluminum airframes, consider using an alcohol-cure RTV such as clear or gray Dow Corning 3145, white General Electric RTV 162 or gray high strength RTV 167, or clear Loctite 5140. These alcohol-cure RTVs are more expensive. Instead of a buck or three, McMaster sells the GE 162 for $12.66 per 2.8 oz tube. http://www.mcmaster.com (part number 74935A65, page 3305) The Dow 3145 is quite a bit more expensive than that. references: http://www.logwell.com/tech/servtips/RTV.html http://www.mgchemicals.com/downloads/appguide/appguide0205-1.pdf http://www.mgchemicals.com/products/silicones/cureguide-1part.html ... and of course Google... ________________________________ Message 10 ____________________________________ Time: 07:14:47 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Rear-Battery version of Z-19 At 10:26 AM 6/18/2007 -0700, you wrote: > >Hi Bob, > >In Z-19/RB, it's called out to use 6" or less 12AWG between the Main and >Engine Battery contactors and their respective busses. Without building a >special mount for this, I could locate these busses close to the >contactors but I would probably need about 15" of wire each. Would your >suggestion be to go to 10AWG in this case? That's not necessary. 12AWG is good for 15+ amps. I doubt that you're going to have battery bus totals that exceed that value! That 6" "rule" is a real loose thing. Obviously a well installed wire that's a bit longer isn't going to present that much increase in crash safety hazard. Bob . . . ________________________________ Message 11 ____________________________________ Time: 08:17:29 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Regulator trouble? At 12:18 PM 6/18/2007 -0400, you wrote: > >I have a slightly different take on this as it seems there might already >be some clues here. > >Shouldn't the field voltage go above 8 volts when the alternator is loaded >on the ground. If it is putting out less that 14.4 volts at low rpm - why >isn't the field voltage up around 12 or 13? High resistance somewhere in >the field? The voltage will go that high only if one approaches the alternator's maximum available output current for that RPM. In this case, he cites a 17A load and ramp idle RPM. >Next I'd want to know why 14.7 volts while taxiing in. Is the regulator >voltage going up when it is hot? Does it not throttle back far enough >under light load? Is there a connection that is high resistance when hot >such that the regulator is sensing 14.4 but putting out 14.7 upstream >where the voltmeter is located? Or is it an inaccurate voltmeter? There's a ton of variables which can stack up to push the setpoint around a bit . . . what we're interested in finding is an instability that accounts for the nuisance trip of an OV protection system set to operate at 16.2 volts or so. >If the connections have already been checked, I'd be tempted to >temporarilly wire in a cheap regulator and see what happens. A cheap regulator wouldn't have the ov protection built in. It WOULD be a useful experiment to temporarily wire in a substitute regulator and a separate OV sensor. I think I've got some hardware laying around we can send him if we don't see something really profound . . . or he's unable to observe a field and bus voltage surge associated with the nuisance trip. 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.