---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 12/20/19: 12 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:47 AM - Troubleshoot Generator (James Meade) 2. 05:59 AM - Re: Troubleshoot Generator (A R Goldman) 3. 08:44 AM - Re: Troubleshoot Generator (Ernest Christley) 4. 09:29 AM - Re: Troubleshoot Generator (Charlie England) 5. 02:25 PM - Re: One battery/two alternators IFR z-diagram (Robert L. Nuckolls, III) 6. 03:03 PM - Re: One battery/two alternators IFR z-diagram (Robert L. Nuckolls, III) 7. 03:46 PM - Re: One battery/two alternators IFR z-diagram (Sebastien) 8. 04:16 PM - Re: One battery/two alternators IFR z-diagram (user9253) 9. 07:02 PM - Re: Troubleshoot Generator (Robert L. Nuckolls, III) 10. 08:00 PM - Re: One battery/two alternators IFR z-diagram (Michael Burbidge) 11. 08:18 PM - Re: Troubleshoot Generator (John B) 12. 08:30 PM - Re: Switch ratings? (David Saylor) ________________________________ Message 1 _____________________________________ Time: 04:47:29 AM PST US Subject: AeroElectric-List: Troubleshoot Generator From: "James Meade" How do you troubleshoot a generator? Piper PA-22-150 Tri-Pacer 1955. First incident. Noticed ammeter discharging in air. Landed. Second incident. After a number of flights all OK, noticed ammeter showed charge at run-up RPM, flew, noticed discharge about 30 minutes later. Don't know when the generator went offline. Unloading various components all indicated the ammeter correctly reflected their draw. Landed. Third incident. Immediately after 2d, started engine and ammeter immediately showed discharge. Wires appear to be tightly connected but too hot for hands in engine compartment for definitive check. Belt was good and had proper tension. Initial calls to "old" mechanics and searching online shows very few people are experienced in generator systems anymore. My next step is to uncowl the plane and with the engine cool get my hands in and check all wires for proper connection and condition. I assume the ammeter is OK based on it's presentation. If I can, I'm going to pull one or more brushes and inspect them. I'd like to isolate the problem to either the voltage regulator or the generator. How do I do that? I intend to get the data plate information on the generator and determine the make, model and type, but I don't have that information right now. I'll post more info when I can but with holiday plans may be limited for a while. ________________________________ Message 2 _____________________________________ Time: 05:59:12 AM PST US From: A R Goldman Subject: Re: AeroElectric-List: Troubleshoot Generator Reminds me of an incident many years in a senica 1 I had. Left engine (could have been a generator) similar symptoms after many a& ps. Finally was sent to an electrical specialist. It turned out that there was a corroded switch due to water inclusion ( switches were below the little storm window or whatever it is called. I think it was the master switch but cant be certain. That was about 40 yrs ago Good luck on your hunt! Rich Sent from my iPhone > On Dec 20, 2019, at 6:43 AM, James Meade wrote: > > > How do you troubleshoot a generator? Piper PA-22-150 Tri-Pacer 1955. > First incident. Noticed ammeter discharging in air. Landed. > Second incident. After a number of flights all OK, noticed ammeter showed charge at run-up RPM, flew, noticed discharge about 30 minutes later. Don't know when the generator went offline. Unloading various components all indicated the ammeter correctly reflected their draw. Landed. > Third incident. Immediately after 2d, started engine and ammeter immediately showed discharge. > Wires appear to be tightly connected but too hot for hands in engine compartment for definitive check. Belt was good and had proper tension. > Initial calls to "old" mechanics and searching online shows very few people are experienced in generator systems anymore. > My next step is to uncowl the plane and with the engine cool get my hands in and check all wires for proper connection and condition. > I assume the ammeter is OK based on it's presentation. > If I can, I'm going to pull one or more brushes and inspect them. > I'd like to isolate the problem to either the voltage regulator or the generator. How do I do that? > I intend to get the data plate information on the generator and determine the make, model and type, but I don't have that information right now. > I'll post more info when I can but with holiday plans may be limited for a while. > > > ________________________________ Message 3 _____________________________________ Time: 08:44:32 AM PST US From: Ernest Christley Subject: Re: AeroElectric-List: Troubleshoot Generator Pull the generator.=C2- Mount it in a drill press.=C2- Adjust the dril l press to run it at various speeds.=C2- Use a heat gun to simulate engin e compartment conditions. On Friday, December 20, 2019, 7:48:04 AM EST, James Meade wrote: .net> How do you troubleshoot a generator?=C2- Piper PA-22-150 Tri-Pacer 1955. First incident.=C2- Noticed ammeter discharging in air.=C2- Landed. Second incident.=C2- After a number of flights all OK, noticed ammeter sh owed=C2- charge at run-up RPM, flew, noticed discharge about 30 minutes later.=C2- Don't know when the generator went offline.=C2- Unloading various compone nts=C2- all indicated the ammeter correctly reflected their draw.=C2- Landed. Third incident.=C2- Immediately after 2d, started engine and ammeter=C2 - immediately showed discharge. Wires appear to be tightly connected but too hot for hands in engine=C2- compartment for definitive check.=C2- Belt was good and had proper tensio n. Initial calls to "old" mechanics and searching online shows very few=C2- people are experienced in generator systems anymore. My next step is to uncowl the plane and with the engine cool get my hands =C2- in and check all wires for proper connection and condition. I assume the ammeter is OK based on it's presentation. If I can, I'm going to pull one or more brushes and inspect them. I'd like to isolate the problem to either the voltage regulator or the=C2 - generator.=C2- How do I do that? I intend to get the data plate information on the generator and determine =C2- the make, model and type, but I don't have that information right now. I'll post more info when I can but with holiday plans may be limited for a =C2- while. =C2- =C2- =C2- =C2- =C2- -Matt Dralle, List Admin. - S - WIKI - - =C2- =C2- =C2- =C2- =C2- -Matt Dralle, List Admin. ________________________________ Message 4 _____________________________________ Time: 09:29:14 AM PST US Subject: Re: AeroElectric-List: Troubleshoot Generator From: Charlie England On 12/20/2019 6:43 AM, James Meade wrote: > > > How do you troubleshoot a generator? Piper PA-22-150 Tri-Pacer 1955. > First incident. Noticed ammeter discharging in air. Landed. > Second incident. After a number of flights all OK, noticed ammeter > showed charge at run-up RPM, flew, noticed discharge about 30 minutes > later. Don't know when the generator went offline. Unloading various > components all indicated the ammeter correctly reflected their draw. > Landed. > Third incident. Immediately after 2d, started engine and ammeter > immediately showed discharge. > Wires appear to be tightly connected but too hot for hands in engine > compartment for definitive check. Belt was good and had proper tension. > Initial calls to "old" mechanics and searching online shows very few > people are experienced in generator systems anymore. > My next step is to uncowl the plane and with the engine cool get my > hands in and check all wires for proper connection and condition. > I assume the ammeter is OK based on it's presentation. > If I can, I'm going to pull one or more brushes and inspect them. > I'd like to isolate the problem to either the voltage regulator or the > generator. How do I do that? > I intend to get the data plate information on the generator and > determine the make, model and type, but I don't have that information > right now. > I'll post more info when I can but with holiday plans may be limited > for a while. Assuming wiring integrity, You're down to the switch, generator brushes/internal connections, and the regulators internal connections. If you still have the the original style regulator on a plane of that age, it would have what amounts to a handful of mechanical relays in it. If the contacts are starting to burn/corrode, it'll cause random failures. You might find that you can remove the cover to inspect the contacts. Charlie ________________________________ Message 5 _____________________________________ Time: 02:25:36 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: One battery/two alternators IFR z-diagram At 08:26 PM 12/18/2019, you wrote: >After doing some reading on the FAQ list, it looks like I should >consider the Z-13/8 with the Z-25 excitation mod, or else the Z-14. >I think I also now understand one of the drawbacks of Z-12 >architecture is if the battery contactor fails, both alternators go offline. > >Michael- That's generally not true with modern alternators . . . and only a few of the legacy alternators. It's true that many alternators will not come online without a battery present . . .but once running, they'll hum along oblivious to battery being there or not. With HEAVY inrush loads like klieg-lights in the wings or hydraulic pump motors. It was theoretically possible to stall an alternator . . .from which recovery would be impossible unless a battery were present. Such loads are rare in our neighborhood of the GA community. Contactor failure in flight is exceedingly rare . . . never heard of one . . . but ANY change to engine cranking performance on the GROUND calls for investigation . . . you might have a contactor getting tired. But if the engine starts right smartly then you've 'preflighted' the contactor . . . probability of loosing it in the next 3 hours of operation is nil. Z-12 is flying in hundreds if not thousands of TC aircraft and they don't even have an e-bus. If you've got a ROBUST standby alternator like the contemporary SD20 machines, then the need for load-shedding with loss of main alternator is minimal if non-existent . . . hence, the need for a refined load-shedding protocol is negated. Of course, this should all be CONFIRMED by completing the very first design document needed for artful crafting of your system . . . the LOAD ANALYSIS. If it were my airplane, I'd go for Z12 with no ebus and a well maintained battery. The auto-switch feature for Z-12 is not necessary for flight safety. I'd run an LR3 on the main alternator and a generic VR166 on the standby alternator. Leave standby alternator OFF until needed as annunciated by a low volts warning. Bob . . . ________________________________ Message 6 _____________________________________ Time: 03:03:56 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: One battery/two alternators IFR z-diagram > >What is there a recommended replacement architecture for the z-13/20? Z13/8 was crafted with the notion of offering a robust (meaning unlimited electrical endurance in the alt-out mode) plan-b for loss of main alternator assuming running loads can be reduced to 10A or less . . . which is the capability of the SD8. I fiddled with the idea of a Z13/20 waayyy back when . . . at time when the operating philosophy for the SD20 called for b-lead current sensing and cockpit indications for reducing load to values at or below the 'rated' output of the alternator. This made the FAA happy . . . but in retrospect was totally unnecessary. The SD20 has a pedigree based on a 40A, automotive, belt driven alternator (B&C's L40). In a Lycoming installation, it runs at 10KRPM or better, may indeed be expected to produce 40A under some conditions and is belt-driven which produces significant axial loading on the bearings. As an SD20, it's DERATED not for any physical design limits . . . but because on the vacuum pump pad it isn't driven at much more than 3900 rpm. So in fact, you cannot physically 'overload' this alternator to the extend that functionality is at risk. Its output sags and it's physically incapable of producing the same output as the mother-machine just 'cause it's not turning fast enough. In years since, materials and processes for the raw-stock have improved such that the SD20 is now rated at more than 20A on a pad drive. The Z13/8 philosophy for minimizing running loads while under standby power is not especially valid for EITHER a Z12 or Z13/20 application. So as mentioned in my post of a few mintues ago, I think I'm going to revise Z-12 to (1) remove the Endurance Bus and (2) replace the standby regulator with something simple and cheap. The best indicator of loading the standby alternator too hard is depression of bus voltage below 13.0 volts. Given the number of voltmeters in most airplanes today, the value of a over-current, under-voltage sensing regulator on the standby system seems something of overkill. Modern electronics and lighting have made it possible to craft even an IFR capable machine with running loads below the output capability of a pad-driven SD20. Have I overlooked anything here? Considered critical review is most welcome . . . Bob . . . ________________________________ Message 7 _____________________________________ Time: 03:46:41 PM PST US From: Sebastien Subject: Re: AeroElectric-List: One battery/two alternators IFR z-diagram Speaking strictly for my applications Bob (VFR and IFR AB, some of which have electrically dependent engines), I totally agree. My ideal system is not bulletproof or dispatcheable after one or more failures. My ideal system is as simple and cheap as possible, while allowing for comfortable termination of flight after a failure. As soon as the bus voltage sags below 13.8v, red lights start flashing in multiple places. Once this happens there is a checklist to follow in each airplane, and manually changing the alternator switch from main to aux is no big deal. 20A is sufficient for comfortable termination of flight, or even load shedding and continuation of flight in many circumstances. I like the idea of an endurance bus, but have never implemented it because the added complexity was not justified by the benefits. On Fri, Dec 20, 2019, 15:09 Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > > What is there a recommended replacement architecture for the z-13/20? > > > Z13/8 was crafted with the notion of offering > a robust (meaning unlimited electrical endurance > in the alt-out mode) plan-b for loss of main alternator > assuming running loads can be reduced to 10A > or less . . . which is the capability of > the SD8. > > I fiddled with the idea of a Z13/20 waayyy > back when . . . at time when the operating > philosophy for the SD20 called for b-lead > current sensing and cockpit indications > for reducing load to values at or below > the 'rated' output of the alternator. > > This made the FAA happy . . . but in retrospect > was totally unnecessary. The SD20 has > a pedigree based on a 40A, automotive, > belt driven alternator (B&C's L40). > In a Lycoming installation, it runs > at 10KRPM or better, may indeed be expected > to produce 40A under some conditions > and is belt-driven which produces significant > axial loading on the bearings. > > As an SD20, it's DERATED not for any physical > design limits . . . but because on the > vacuum pump pad it isn't driven at much > more than 3900 rpm. So in fact, you cannot > physically 'overload' this alternator to the > extend that functionality is at risk. > Its output sags and it's physically incapable > of producing the same output as the mother-machine > just 'cause it's not turning fast enough. > > In years since, materials and processes for > the raw-stock have improved such that the > SD20 is now rated at more than 20A on a > pad drive. > > The Z13/8 philosophy for minimizing running > loads while under standby power is not > especially valid for EITHER a Z12 or Z13/20 > application. > > So as mentioned in my post of a few mintues > ago, I think I'm going to revise Z-12 to (1) > remove the Endurance Bus and (2) replace the > standby regulator with something simple and > cheap. The best indicator of loading the standby > alternator too hard is depression of bus > voltage below 13.0 volts. Given the number > of voltmeters in most airplanes today, the > value of a over-current, under-voltage sensing > regulator on the standby system seems something > of overkill. > > Modern electronics and lighting have made it > possible to craft even an IFR capable machine > with running loads below the output capability > of a pad-driven SD20. > > Have I overlooked anything here? Considered > critical review is most welcome . . . > > Bob . . . > ________________________________ Message 8 _____________________________________ Time: 04:16:19 PM PST US Subject: AeroElectric-List: Re: One battery/two alternators IFR z-diagram From: "user9253" > So as mentioned in my post of a few mintues > ago, I think I'm going to revise Z-12 to (1) > remove the Endurance Bus and (2) replace the > standby regulator with something simple and > cheap. The best indicator of loading the standby > alternator too hard is depression of bus > voltage below 13.0 volts. Given the number > of voltmeters in most airplanes today, the > value of a over-current, under-voltage sensing > regulator on the standby system seems something > of overkill. > Modern electronics and lighting have made it > possible to craft even an IFR capable machine > with running loads below the output capability > of a pad-driven SD20. > Have I overlooked anything here? Considered > critical review is most welcome . . . > Bob . . . Great idea Bob. Simpler is better. Many VFR sport planes do not even need a standby alternator. Now if we could just convince builders to NOT install an avionics switch. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=493911#493911 ________________________________ Message 9 _____________________________________ Time: 07:02:01 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Troubleshoot Generator At 06:43 AM 12/20/2019, you wrote: > > >How do you troubleshoot a generator? Piper PA-22-150 Tri-Pacer 1955. Took dual instruction from the one-and-only Rip Gooch off Rawdon field in 1962 in one of those. Still one of my favorite airplanes. >First incident. Noticed ammeter discharging in air. Landed. >Second incident. After a number of flights all OK, noticed ammeter showed >charge at run-up RPM, flew, noticed discharge about 30 minutes later. >Don't know when the generator went offline. Unloading various components >all indicated the ammeter correctly reflected their draw. Landed. >Third incident. Immediately after 2d, started engine and ammeter >immediately showed discharge. The most probable cause is brushes worn down beyond limits. These should be part of the annual inspection for wear limits. If the regulator is an 'original' electro-mechnanical, then it's suspect . . . and if very old . . . probably needs replacing 'just because. It's no surprise that few mechanics can deal with these old machines 'legally' . . . they don't have practice, knowledge or documentation. B&C probably has an STC for an L40 alternator installation. Yeah, it would be 'nice' to keep it 'stock' . . . but it's the best upgrade you could do for this venerable Bob . . . ________________________________ Message 10 ____________________________________ Time: 08:00:51 PM PST US From: Michael Burbidge Subject: Re: AeroElectric-List: One battery/two alternators IFR z-diagram Thanks for the detailed response Bob. You=92ve probably responded to this q uestion before. I looked for the archive of this mail list. But couldn=92t find it. Is there an archive. I could swear I=92ve used it before. Michael From: "owner-aeroelectric-list-server@matronics.com" on behalf of "Robert L. Nuckolls, III" m> Subject: Re: AeroElectric-List: One battery/two alternators IFR z-diagram What is there a recommended replacement architecture for the z-13/20? Z13/8 was crafted with the notion of offering a robust (meaning unlimited electrical endurance in the alt-out mode) plan-b for loss of main alternator assuming running loads can be reduced to 10A or less . . . which is the capability of the SD8. I fiddled with the idea of a Z13/20 waayyy back when . . . at time when the operating philosophy for the SD20 called for b-lead current sensing and cockpit indications for reducing load to values at or below the 'rated' output of the alternator. This made the FAA happy . . . but in retrospect was totally unnecessary. The SD20 has a pedigree based on a 40A, automotive, belt driven alternator (B&C's L40). In a Lycoming installation, it runs at 10KRPM or better, may indeed be expected to produce 40A under some conditions and is belt-driven which produces significant axial loading on the bearings. As an SD20, it's DERATED not for any physical design limits . . . but because on the vacuum pump pad it isn't driven at much more than 3900 rpm. So in fact, you cannot physically 'overload' this alternator to the extend that functionality is at risk. Its output sags and it's physically incapable of producing the same output as the mother-machine just 'cause it's not turning fast enough. In years since, materials and processes for the raw-stock have improved such that the SD20 is now rated at more than 20A on a pad drive. The Z13/8 philosophy for minimizing running loads while under standby power is not especially valid for EITHER a Z12 or Z13/20 application. So as mentioned in my post of a few mintues ago, I think I'm going to revise Z-12 to (1) remove the Endurance Bus and (2) replace the standby regulator with something simple and cheap. The best indicator of loading the standby alternator too hard is depression of bus voltage below 13.0 volts. Given the number of voltmeters in most airplanes today, the value of a over-current, under-voltage sensing regulator on the standby system seems something of overkill. Modern electronics and lighting have made it possible to craft even an IFR capable machine with running loads below the output capability of a pad-driven SD20. Have I overlooked anything here? Considered critical review is most welcome . . . Bob . . . ________________________________ Message 11 ____________________________________ Time: 08:18:09 PM PST US From: John B Subject: Re: AeroElectric-List: Troubleshoot Generator One can inspect/replace the brushes, but, really, after many decades of service, the generator likely wore out due to corrosion of the internal parts. Bearings slowly fail, the brushes then wear at a more rapid rate. If the generator was serviced/replaced, this was likely done in the 70s or 80s... True: There are very few mechanics or shops that can service this generator. An alternator, legally installed via an STC, and a new battery, will likely solve all the problems. The alternator will likely be lighter than the generator, and the aircraft's Weight & Balance will need to be updated. This is an easy task... Install a new belt as well. That might well come in the kit... On Fri, Dec 20, 2019 at 9:07 PM Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > At 06:43 AM 12/20/2019, you wrote: > > jnmeade@southslope.net> > > How do you troubleshoot a generator? Piper PA-22-150 Tri-Pacer 1955. > > > Took dual instruction from the one-and-only Rip Gooch > off Rawdon field in 1962 in one of those. Still one > of my favorite airplanes. > > First incident. Noticed ammeter discharging in air. Landed. > Second incident. After a number of flights all OK, noticed ammeter > showed > charge at run-up RPM, flew, noticed discharge about 30 minutes later. > Don't know when the generator went offline. Unloading various components > all indicated the ammeter correctly reflected their draw. Landed. > Third incident. Immediately after 2d, started engine and ammeter > immediately showed discharge. > > > The most probable cause is brushes worn down beyond > limits. These should be part of the annual inspection > for wear limits. If the regulator is an 'original' > electro-mechnanical, then it's suspect . . . and if > very old . . . probably needs replacing 'just because. > > It's no surprise that few mechanics can deal with > these old machines 'legally' . . . they don't > have practice, knowledge or documentation. B&C > probably has an STC for an L40 alternator installation. > Yeah, it would be 'nice' to keep it 'stock' . . . but > it's the best upgrade you could do for this venerable > > > Bob . . . > ________________________________ Message 12 ____________________________________ Time: 08:30:26 PM PST US From: David Saylor Subject: Re: AeroElectric-List: Switch ratings? "Aircraft Power 2" inputs for nine devices (almost everything), plus AP servos and trim. Endurance and anti-sag. As I understand it, Aircraft Power 1 and Aircraft Power 2 are "dioded" (Garmin's word) apart. The highest voltage feeds the device. On Thu, Dec 19, 2019 at 9:16 AM Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > A single feed endurance bus with a switch > in the feeder . . . what 'lectro-whizzies > run from this bus? > > 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.