---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 06/18/21: 10 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 09:54 AM - Re: Is there a switch configuration that will do this? (user9253) 2. 11:54 AM - Re: Re: Is there a switch configuration that will do this? (David Carter) 3. 12:49 PM - Re: Dual alternators (Peter Pengilly) 4. 01:15 PM - Re: Re: Is there a switch configuration that will do this? (Robert L. Nuckolls, III) 5. 01:27 PM - Re: Dual alternators (Robert L. Nuckolls, III) 6. 02:10 PM - Re: Re: Is there a switch configuration that will do this? (David Carter) 7. 02:12 PM - Re: Dual alternators (Kelly McMullen) 8. 09:34 PM - Re: Dual alternators (Robert L. Nuckolls, III) 9. 11:07 PM - Re: Dual alternators (tiyaverma) 10. 11:10 PM - Re: Dual alternators (tiyaverma) ________________________________ Message 1 _____________________________________ Time: 09:54:29 AM PST US Subject: AeroElectric-List: Re: Is there a switch configuration that will do this? From: "user9253" You need a DP3T ON-ON-ON switch. Mouser and Digikey and others sell them. https://www.mouser.com/Electromechanical/Switches/Toggle-Switches/_/N-5g2jZ1yzvvqx?P=1z0z2o3Z1z0z28f https://www.digikey.com/en/products/filter/toggle-switches/201?s=N4IgjCBcpgzADFUBjKAzAhgGwM4FMAaEAeygG0RYAWeWAdgE4QBdIgBwBcoQBlDgJwCWAOwDmIAL5EATLACsSEKkiZchEuUoAOafABseluy6ReAkeKkgAtNMXKBAV3WlIFBcwlW7bkABEABVgAFRYJIA -------- Joe Gores Read this topic online here: http://forums.matronics.com/viewtopic.php?p=502430#502430 ________________________________ Message 2 _____________________________________ Time: 11:54:47 AM PST US From: David Carter Subject: Re: AeroElectric-List: Re: Is there a switch configuration that will do this? >> You need a DP3T ON-ON-ON switch. Joe - thank you, it appears that would work electrically. It took me a few minutes to decipher the actions of this switch, but I got there. However, I have not yet found one in a form factor that would match the rest of the standard toggles in my panel. I may have to just live with two switches. It's not the end of the world, but it's not as elegant. Thanks! --- David Carter david@carter.net ________________________________ Message 3 _____________________________________ Time: 12:49:53 PM PST US From: "Peter Pengilly" Subject: RE: AeroElectric-List: Dual alternators In Diamond twins one regulator is the master and has the job of balancing the alternators. I=99m not actually sure how it achieves that, but works well most of the time. The regulators are provided by the engine mfrs (Continental or Austro). The G1000 instrumentation systems use hall effect sensors to detect the output of each alternator. The regulators use a different sensor to do their job. Can result in the G1000 saying the loads are unbalanced, which makes pilots unhappy =93 although voltage is always good. I have spent a lot of time troubleshooting, reloading G1000 software and other stuff to cure what seems to be an imaginary problem. Peter From: owner-aeroelectric-list-server@matronics.com On Behalf Of Robert L. Nuckolls, III Sent: 17 June 2021 18:21 Subject: Re: AeroElectric-List: Dual alternators I've imagined, but never tested, that running two alternators that are feeding a single battery bus would be dominated by current from one of the alternators. My reasoning is that regardless of how closely the charge systems are matched, small variations would result in a slightly higher output voltage on one of them. This would then result in an even lower output from the lower voltage output charge system, which would reduce its current contribution. Yes, until system loads exceeded the capacity of the alternator with the higher set-point. The bus voltage sags allowing the lower set-point alternator to wake up and begin to support the load. This is what happens with a B&C standby alternator system. #2 alternator is set to some lower-than-nominal regulation voltage. Should the #1 alternator quit, voltage sags and #2 wakes up. Similarly, should the #1 alternator suffer an open winding with subsequent loss of capacity, the voltage might sag and again, #2 steps in to take up the slack. In both cases, #1 alternator is running maxed out whether by reason of total system loads =or= loss of capacity. If the above assumptions are accurate, how would it change if the two alternators shared a single regulator? (I=C3=A2=82=AC=84=A2m not advocating this arrangement) Cessna 336/337 Models do just that. Beech Barons too. There is a switch for bringing a second regulator into service should the first one fail. This philosophy does produce a system whereby the two alternator ammeters track each other fairly closely . . . in my not so humble opinion, a totally misguided practice to keep pilot's 'happy'. There is no practical NEED for balancing the loads on two alternators assuming (1) either alternator can carry 100% of ships loads with (2) demonstrated adequacy of cooling. This shade-tree 'paralleling' scheme creates single points of failure for both alternators. How this got past in-house DERs is a mystery to me . . . how the FAA bought it is a . . . well . . . I won't go there. Would the result change If the two alternators were PMA units, mechanically tied together and producing a sin wave 'in-phase.' The engines cannot be synchronized that tightly. One final question I've wondered about. How do twin engine planes with two alternators manage (my assumed) tendency for two alternators in parallel quickly relying on the larger voltage out unit for most of the current? They parallel fields on a single regulator. I designed a true paralleling regulator proposal for Cessna on the 303 Crusader program thinking that there was a HUGH after market opportunity to put the system on new and fielded Barons and Skymasters. I don't know how the Cessna West was wiring their airplanes. In any case, Cessna East didn't bite on the idea so I was never funded to pursue the design. Twin Generators on earlier Cessna and Beech models WERE fitted with paralleling regulators which DID NOT compromise independence of the two system. Turbine twins have always enjoyed that design philosophy. Here is a sketch on a generator paralleling system on a Beech Model 18 I think . . . but typical of all dual generator twins of the era. http://aeroelectric.com/Pictures/Schematics/Parallel_Aircraft_Generators. jpg This design uses voltage drop in the generator's compensation windings as a current shunt. Any difference in those two voltages biases the voltage sense windings to depress excitation to the generator with the higher load while elevating excitation on the lighter loaded machine . . . pretty slick. Bob . . . Un impeachable logic: George Carlin asked, "If black boxes survive crashes, why don't they make the whole airplane out of that stuff?" ________________________________ Message 4 _____________________________________ Time: 01:15:52 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Is there a switch configuration that will do this? >However, I have not yet found one in a form factor that would match >the rest of the standard toggles in my panel. What switches are you using? Bob . . . Un impeachable logic: George Carlin asked, "If black boxes survive crashes, why don't they make the whole airplane out of that stuff?" ________________________________ Message 5 _____________________________________ Time: 01:27:34 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Dual alternators > >Thanks Bob, now that is amazing engineering, zero PN junctions, must >be near bulletproof. >Cheers, >Brian. Pretty close. If memory serves, some versions of these regulators came with field remover/refurbish/ replace manuals. They're stone simple in their physics of operation and very repairable as long as they were not abused. Bob . . . Un impeachable logic: George Carlin asked, "If black boxes survive crashes, why don't they make the whole airplane out of that stuff?" ________________________________ Message 6 _____________________________________ Time: 02:10:38 PM PST US From: David Carter Subject: Re: AeroElectric-List: Re: Is there a switch configuration that will do this? >> What switches are you using? It appears that Stein's crew is putting these in by default unless I ask for something else. https://www.steinair.com/product/toggle-switch-spst-onoff-fast-on-terminals/ --- David Carter david@carter.net > ________________________________ Message 7 _____________________________________ Time: 02:12:18 PM PST US Subject: Re: AeroElectric-List: Dual alternators From: Kelly McMullen I was under the impression that the Diamond twins either had Austro (originally Thielert) diesel engines or Lycoming avgas engines. Where did Continental come in? On 6/18/2021 12:48 PM, Peter Pengilly wrote: > In Diamond twins one regulator is the master and has the job of > balancing the alternators. > > Im not actually sure how it achieves that, but works well most of the time. > > The regulators are provided by the engine mfrs (Continental or Austro). ________________________________ Message 8 _____________________________________ Time: 09:34:25 PM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Dual alternators At 02:48 PM 6/18/2021, you wrote: >In Diamond twins one regulator is the master and >has the job of balancing the alternators. > >I=99m not actually sure how it achieves that, but works well most of the time. Is there a .pdf of the alternator wiring you could share? Sounds like an interesting system I'd like to understand. Bob . . . Un impeachable logic: George Carlin asked, "If black boxes survive crashes, why don't they make the whole airplane out of that stuff?" ________________________________ Message 9 _____________________________________ Time: 11:07:33 PM PST US Subject: AeroElectric-List: Re: Dual alternators From: "tiyaverma" Extremely inspired! Everything is extremely open Chandigarh Escorts Service (http://www.rashmibhargav.in/) clear illumination of issues. It contains really certainties. Read this topic online here: http://forums.matronics.com/viewtopic.php?p=502444#502444 ________________________________ Message 10 ____________________________________ Time: 11:10:04 PM PST US Subject: AeroElectric-List: Re: Dual alternators From: "tiyaverma" Incredible articles and awesome design. Your forum post entry merits the greater part of the positive input Chandigarh Escorts (http://www.chandigarhescortsgirl.com/) it"s been getting. I want to steer about this, for the explanation that it's useful. 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