AeroElectric-List Digest Archive

Mon 06/11/18


Total Messages Posted: 10



Today's Message Index:
----------------------
 
     1. 01:48 AM - Re: Re: Rotax Charging System (Robert L. Nuckolls, III)
     2. 07:51 AM - Re: Re: Rotax Charging System (Sebastien)
     3. 08:25 AM - Re: Rotax Charging System (user9253)
     4. 09:22 AM - Re: Re: Rotax Charging System (Sebastien)
     5. 10:04 AM - Re: Re: Rotax Charging System (Robert L. Nuckolls, III)
     6. 10:13 AM - Re: Re: Rotax Charging System (FLYaDIVE)
     7. 11:16 AM - Re: Rotax Charging System (user9253)
     8. 11:28 AM - Re: Re: Rotax Charging System (Sebastien)
     9. 11:57 AM - Re: Re: Rotax Charging System (Richard E. Tasker)
    10. 06:45 PM - Re: Alternator Noise When Touching Metal Airframe Grounds (Jared Yates)
 
 
 


Message 1


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    Time: 01:48:29 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Rotax Charging System
    At 01:01 PM 6/10/2018, you wrote: >Whoops, sorry all, wrong address for the last email. > >On Sun, Jun 10, 2018 at 10:59 AM, Sebastien ><<mailto:cluros@gmail.com>cluros@gmail.com> wrote: >If it's the easy failure then great but I really don't know how to >tell the difference between a gen failure and a regulator failure. >My regulator is $12 so I keep a spare and would just swap that out. >I guess your first line of attack should be as you said: inspect all >the wiring you can find for an obvious break / bad ground / short / >loose connector / unplugged wire. Give each PIDG connector a strong >pull to see if it comes apart. You should be able to hold the >connector in one hand and pull the other wire pretty much as hard as >you can (it should support a 50 pound pull no problem). the fist like of attack in any failure resolution is to make measurements. In the case of PM alternator rectifier-regulator systems, we know that the output of the alternator is an AC voltage that is proportional to engine RPM. We also know that the device is electrically simple . . . an array of windings of wire on a stator. No brushes. So to start with, get out an ohmmeter and look at the resistance of the windings. Make a measurement between the two or three wires that come out of the device. The readings will be quite low . . . under one ohm. His is where a low resistance ohmmeter described in the 'Connection and discussed on these pages would be handy. The resistance between any two wires of a three phase alternator should be nearly identical. Variations between pairs suggests shorted turns on the stator windings. If the alternator is a single phase, then the ohmmeter test only tells you that there is continuity . . . shorted turns would be revealed only by knowing what the resistance of the new, undamaged coil. Then measure from the windings to engine crankcase. This reading should always be 'infinite' . . . meaning that it's too high for your instrument to measure. Usually in excess of 20,000,000 ohms. You could make an AC measurement of voltage at the output wires with the engine running. Idle RPM is fine. Knowing what the voltage is for a new, known good alternator is a handy thing to know. Assuming all the above produces no hint of a fault, then the only thing left is the rectifier-regulator. We know that the Ducatti product is not robust. For a solid state device not to operate for the lifetime of the airplane is a pretty rare condition in the automotive world. The thing has a poor demonstrated track record in aviation . . . no doubt similarly poor in the motorcycle world from which I think it hails. There are dozens of PMA/RR systems on various sport and utility vehicles where the RR is no doubt beefier than the Rotax Ducatti offering. You are at little risk for trying one of them . . . A John Deere product has been mentioned. I think it's similar to the device favored by the Corvair conversions crowd . . . there's a 30A PMA/RR system they favor. The most common problem with the constellation of off the shelf RR products is lack of adjustability for regulation set point. Listers have complained about the less than ideal charging voltage offered by various 'bricks' with no adjusting screws. The core principals for evaluating normal performance and/or trouble shooting are MEASUREMENTS. Lord Kelvin once opined: "I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science, whatever the matter may be." Having the tools with which to explore 'the numbers' in a system that functions well are keys to discovering how to make it work better . . . or to repair the thing when it quits. As the honorable Lord Kelvin suggests, the numbers are foundations for understanding how things work. Bob . . .


    Message 2


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    Time: 07:51:33 AM PST US
    From: Sebastien <cluros@gmail.com>
    Subject: Re: Rotax Charging System
    Thank you for the reply Bob. I thought that the normal Rotax system was a generator, not an alternator. Is this correct? On Mon, Jun 11, 2018, 1:53 AM Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > At 01:01 PM 6/10/2018, you wrote: > > Whoops, sorry all, wrong address for the last email. > > On Sun, Jun 10, 2018 at 10:59 AM, Sebastien <cluros@gmail.com> wrote: > > If it's the easy failure then great but I really don't know how to tell > the difference between a gen failure and a regulator failure. My regulator > is $12 so I keep a spare and would just swap that out. I guess your first > line of attack should be as you said: inspect all the wiring you can find > for an obvious break / bad ground / short / loose connector / unplugged > wire. Give each PIDG connector a strong pull to see if it comes apart. You > should be able to hold the connector in one hand and pull the other wire > pretty much as hard as you can (it should support a 50 pound pull no > problem). > the fist like of attack in any failure resolution > is to make measurements. In the case of PM alternator > rectifier-regulator systems, we know that the output > of the alternator is an AC voltage that is proportional > to engine RPM. We also know that the device is electrically > simple . . . an array of windings of wire on a stator. > No brushes. > > So to start with, get out an ohmmeter and look > at the resistance of the windings. Make a measurement > between the two or three wires that come out of the > device. The readings will be quite low . . . under > one ohm. His is where a low resistance ohmmeter > described in the 'Connection and discussed on > these pages would be handy. > > The resistance between any two wires of a three > phase alternator should be nearly identical. > Variations between pairs suggests shorted turns > on the stator windings. If the alternator is > a single phase, then the ohmmeter test only > tells you that there is continuity . . . shorted > turns would be revealed only by knowing what > the resistance of the new, undamaged coil. > > Then measure from the windings to engine > crankcase. This reading should always be > 'infinite' . . . meaning that it's too high > for your instrument to measure. Usually > in excess of 20,000,000 ohms. > > You could make an AC measurement of voltage at > the output wires with the engine running. > Idle RPM is fine. Knowing what the voltage is > for a new, known good alternator is a handy > thing to know. > > Assuming all the above produces no hint > of a fault, then the only thing left is the > rectifier-regulator. We know that the Ducatti > product is not robust. For a solid state > device not to operate for the lifetime of the > airplane is a pretty rare condition in the > automotive world. The thing has a poor demonstrated > track record in aviation . . . no doubt similarly > poor in the motorcycle world from which I think > it hails. > > There are dozens of PMA/RR systems on various > sport and utility vehicles where the RR is > no doubt beefier than the Rotax Ducatti offering. > You are at little risk for trying one of them . . . > A John Deere product has been mentioned. I think > it's similar to the device favored by the Corvair > conversions crowd . . . there's a 30A PMA/RR > system they favor. > > The most common problem with the constellation > of off the shelf RR products is lack of adjustability > for regulation set point. Listers have complained > about the less than ideal charging voltage offered > by various 'bricks' with no adjusting screws. > > The core principals for evaluating normal > performance and/or trouble shooting are MEASUREMENTS. > > Lord Kelvin once opined: " > > > *I often say that when you can measure what you are speaking about, and > express it in numbers, you know something about it; but when you cannot > measure it, when you cannot express it in numbers, your knowledge is of > a meagre and unsatisfactory kind; it may be the beginning of knowledge, > but you have scarcely, in your thoughts, advanced to the stage of > science, whatever the matter may be."* > > Having the tools with which to explore 'the numbers' > in a system that functions well are keys to discovering > how to make it work better . . . or to repair the > thing when it quits. As the honorable Lord Kelvin > suggests, the numbers are foundations for understanding > how things work. > > > Bob . . . >


    Message 3


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    Time: 08:25:23 AM PST US
    Subject: Re: Rotax Charging System
    From: "user9253" <fransew@gmail.com>
    It seems that generator, alternator, and dynamo have all been used interchangeably. I prefer to use dynamo. Rotax literature calls it a generator. Many Americans call it an alternator. The important thing is to understand how it works. Permanent magnets attached to a spinning engine flywheel move past stationary coils of wire resulting in induced alternating current. -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=480790#480790


    Message 4


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    Time: 09:22:22 AM PST US
    From: Sebastien <cluros@gmail.com>
    Subject: Re: Rotax Charging System
    Oh, well that explains a lot. I thought it was a "generator" with brushes making DC current. Thank you Joe. Any luck on a part number or a way to determine an appropriate John Deere regulator? On Mon, Jun 11, 2018 at 8:24 AM, user9253 <fransew@gmail.com> wrote: > > It seems that generator, alternator, and dynamo have all been used > interchangeably. I prefer to use dynamo. Rotax literature calls it a > generator. Many Americans call it an alternator. The important thing is > to understand how it works. Permanent magnets attached to a spinning > engine flywheel move past stationary coils of wire resulting in induced > alternating current. > > -------- > Joe Gores > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=480790#480790 > >


    Message 5


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    Time: 10:04:23 AM PST US
    From: "Robert L. Nuckolls, III" <nuckolls.bob@aeroelectric.com>
    Subject: Re: Rotax Charging System
    At 11:21 AM 6/11/2018, you wrote: >Oh, well that explains a lot. I thought it was a "generator" with >brushes making DC current. The only place brushed generators are used these days is on turbine engines where the motor that starts the engine becomes a generator when the engine is running. If it's a piston engine, the power source will be some form of alternator. When the alternator is built into the engine, it will generally be a Permanent Magnet device. On the 912/914 Rotax engines . . . Emacs! A stator assembly (9) carries the power generation windings along with special coils that power dual ignition system. These windings are 'charged' by magnets in a flywheel hub (18) on the crankshaft. Bob . . .


    Message 6


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    Time: 10:13:50 AM PST US
    From: FLYaDIVE <flyadive@gmail.com>
    Subject: Re: Rotax Charging System
    A DC Generator uses SLIP-RINGS. A AC Generator uses a COMMUTATOR. BRUSHES are used on both applications. A ALTERNATOR develops AC and then it is RECTIFIED to DC using Diodes. Why? Because it is more efficient and cost wise more practical to create AC an rectify it to DC. There are way too many definitions of a DYNOMOTOR. Some were mechanically driven. Some were electrically driven. Some were driven at 400 Hz with a DC output. Some used a Mechanical Multi-vibrator to produce AC to drive it and then it had a DC output via Slip-Rings. Today the term has changed to include DYNAMETER aka DYNO which are used to determine Horse Power. Barry On Mon, Jun 11, 2018 at 12:21 PM, Sebastien <cluros@gmail.com> wrote: > Oh, well that explains a lot. I thought it was a "generator" with brushes > making DC current. > > Thank you Joe. Any luck on a part number or a way to determine an > appropriate John Deere regulator? > > On Mon, Jun 11, 2018 at 8:24 AM, user9253 <fransew@gmail.com> wrote: > >> >> It seems that generator, alternator, and dynamo have all been used >> interchangeably. I prefer to use dynamo. Rotax literature calls it a >> generator. Many Americans call it an alternator. The important thing is >> to understand how it works. Permanent magnets attached to a spinning >> engine flywheel move past stationary coils of wire resulting in induced >> alternating current. >> >> -------- >> Joe Gores >> >> >> >> >> Read this topic online here: >> >> http://forums.matronics.com/viewtopic.php?p=480790#480790 >> >> >> >> >> >> >> =================================== >> - >> Electric-List" rel="noreferrer" target="_blank">http://www.matronics.com/ >> Navigator?AeroElectric-List >> =================================== >> FORUMS - >> eferrer" target="_blank">http://forums.matronics.com >> =================================== >> WIKI - >> errer" target="_blank">http://wiki.matronics.com >> =================================== >> b Site - >> -Matt Dralle, List Admin. >> rel="noreferrer" target="_blank">http://www.matronics.com/contribution >> =================================== >> >> >> >> >


    Message 7


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    Time: 11:16:01 AM PST US
    Subject: Re: Rotax Charging System
    From: "user9253" <fransew@gmail.com>
    Search eBay for AM101406 or MIA881279 Chances are that the $20 ones are the same as the more expensive ones. Note that the terminals are arraigned in a different order than the Ducati. The mounting holes are also spaced differently. Be sure to use heat conductive grease on the mounting base to carry heat away. > Any luck on a part number or a way to determine an appropriate John Deere regulator? -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=480794#480794


    Message 8


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    Time: 11:28:50 AM PST US
    From: Sebastien <cluros@gmail.com>
    Subject: Re: Rotax Charging System
    Thank you Joe and thank you all. I think we now have a good plan for tackling this problem. On Mon, Jun 11, 2018 at 11:15 AM, user9253 <fransew@gmail.com> wrote: > > Search eBay for AM101406 or MIA881279 > Chances are that the $20 ones are the same as the more expensive ones. > Note that the terminals are arraigned in a different order than the > Ducati. The mounting holes are also spaced differently. Be sure to use > heat conductive grease on the mounting base to carry heat away. > > > Any luck on a part number or a way to determine an appropriate John > Deere regulator? > > > -------- > Joe Gores > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=480794#480794 > >


    Message 9


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    Time: 11:57:19 AM PST US
    Subject: Re: Rotax Charging System
    From: "Richard E. Tasker" <retasker@optonline.net>
    When talking about automotive or aviation devices, it is the AC generator (alternator) that uses slip rings and a DC generator that uses a commutator. The AC generator creates DC with diodes. A DC generator creates DC using the commutator to feed the same polarity to the output as the rotor rotates. Dick Tasker FLYaDIVE wrote: > A DC Generator uses SLIP-RINGS. > A AC Generator uses a COMMUTATOR. > BRUSHES are used on both applications. > A ALTERNATOR develops AC and then it is RECTIFIED to DC using Diodes. > Why? Because it is more efficient and cost wise more practical to create AC an rectify it to DC. > There are way too many definitions of a DYNOMOTOR. > Some were mechanically driven. > Some were electrically driven. > Some were driven at 400 Hz with a DC output. > Some used a Mechanical Multi-vibrator to produce AC to drive it and then it had a DC output via Slip-Rings. > Today the term has changed to include DYNAMETER aka DYNO which are used to determine Horse Power. > > Barry > > > On Mon, Jun 11, 2018 at 12:21 PM, Sebastien <cluros@gmail.com <mailto:cluros@gmail.com>> wrote: > > Oh, well that explains a lot. I thought it was a "generator" with brushes making DC current. > > Thank you Joe. Any luck on a part number or a way to determine an appropriate John Deere regulator? > > On Mon, Jun 11, 2018 at 8:24 AM, user9253 <fransew@gmail.com <mailto:fransew@gmail.com>> wrote: > > > It seems that generator, alternator, and dynamo have all been used interchangeably. I prefer to use dynamo. Rotax literature calls it a generator. Many Americans call it an alternator. > The important thing is to understand how it works. Permanent magnets attached to a spinning engine flywheel move past stationary coils of wire resulting in induced alternating current. > > -------- > Joe Gores > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=480790#480790 <http://forums.matronics.com/viewtopic.php?p=480790#480790> > > > ========== > - > Electric-List" rel="noreferrer" target="_blank">http://www.matronics.com/ <http://www.matronics.com/>Navigator?AeroElectric-List > ========== > FORUMS - > eferrer" target="_blank">http://forums.matronics.com <http://forums.matronics.com> > ========== > WIKI - > errer" target="_blank">http://wiki.matronics.com <http://wiki.matronics.com> > ========== > b Site - > -Matt Dralle, List Admin. > rel="noreferrer" target="_blank">http://www.matronics.com/ <http://www.matronics.com/>contribution > ========== > >


    Message 10


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    Time: 06:45:18 PM PST US
    From: Jared Yates <email@jaredyates.com>
    Subject: Re: Alternator Noise When Touching Metal Airframe Grounds
    Thanks for your help Bob. It's a 4-place airplane with stereo panel-powered Lemo jacks, parallel two-plug jacks (all isolated from the airframe) and a PS Engineering PAR100EX audio panel/intercom. In the past I've played with the volume controls but didn't think to try it out on this most recent flight. In the past, the noise was reduced when I turned down the intercom volume level, or the local headset level on the Bose X. On Sun, Jun 10, 2018 at 12:36 PM, Robert L. Nuckolls, III < nuckolls.bob@aeroelectric.com> wrote: > At 09:21 PM 6/9/2018, you wrote: > > I've always had various levels of alternator and strobe noise in my audio > system, and have never been able to track down and eliminate the problem. > Today I was flying lots of short hops in the warm weather, sweating more > than usual, and I noticed an interesting clue. > > The noise got much louder when I touched the metal part of the push/pull > throttle control. So then I tried the mixture, and prop controls, same > thing. Then I tried the ceiling-mounted aluminum elevator trim wheel (whi ch > doesn't connect to the engine, of course), same thing. Touching the screw s > that hold the instrument panel in place, or the aluminum air vent in the > panel did not generate the noise.=C3=82 > > I'm not really sure where the circuit path is in this case. The headset > only makes contact with me through insulators like the leather ear seal > covers and the furry pad at the top. My shoes have rubber soles, and seat > upholstery is the only other thing I'm in contact with. > > Has anyone encountered this before, and figured out what was causing it? > It almost reminds me of being able to make noise by pointing my fingers > near the heated windshield of some old plane I flew once. Sort of a > windshield theremin > > > Have you run the traps on seeking to discover > at what point noise is entering the system? > What volume controls or switches have an > effect on the noise you hear? What does > your audio system look like? Stereo phones? > > > Bob . . . >




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