Home » Public Forums » GMCnet » Muliple Alterators (5)
| Muliple Alterators (5) [message #156705] |
Sat, 14 January 2012 19:42  |
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John Heslinga
Messages: 632
Registered: February 2011
Location: Edmonton, Alberta, Canada
Karma: 4
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Aaaahaaa!!!
I knew you wanted to drive some sound or communication electronics!! Not many standard creature comforts in a standard RV would need that much power. For curiosity sake, I've tried finding how to control all of those alternators and how to wire them up but have not been able to.
Finally: someone who knows. Looks like your the expert I've been looking for. I have a lot of questions but these two would give clues to their answers.
I know that some installations are simply twin, isolated systems but once you get into 3 or more alternators they aren't
Question 1
My thoughts are that each internal regulator would not be exactly the same and wiring resistances to each regulator would mean that the field coils would not energize exactly the same. That would mean that the output voltage of some would be slightly different. That difference would mean that the higher output voltage alternators would disable the lower voltage alternator resulting in unequal loading of each alternator and your total available current would not be as expected. Do you only use one regulator with a sense wire to the system that controls all field windings? And is the output of each alternator simply hooked to each other and the battery?
Question 2
As long as the battery will maintain system voltage there would be no problem. (good battery) But given that a battery needing charging will just about take all the current a charging system is able to give until it's voltage is high enough. ( the regulator only controls voltage) (especially if it is close to dead or with a dead cell). Would the high current want to boil the batteries (or maybe fry is a better word).
Would you mind please outlining how they are wired and controlled.especially if one is using 5 or 6 alternators.
BTW. I cannot see myself ever doing this to my GMC , but I know of a few people who want to shake the windows of 20 cars on either side of them.
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta
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| Re: Muliple Alterators (5) [message #156731 is a reply to message #156705] |
Sat, 14 January 2012 22:49  |
RadioActiveGMC
Messages: 1020
Registered: November 2010
Location: Hot AZ desert
Karma: 0
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I'd be glad to assist. If you email me I'll Find out what system your rwanting to run. The only part I've not done was to figure out belt configuration and always got helpon that. Plus welding the brackets together not my thing at lest yet something I want to learn.. I've got a few pics I can share as well but they are before the days of digital. When I lived in south Carolina we used to set up massive systems. Huge rf amplifiers and large stereo amps for competitions. Right now I'm on the Mexico border with the family and typing on my iPad. Send me a email...
Ps ... Does the fellow that drives the yellow gmc on the ca side of las algodones Mexico follow this forum?? I've seen this gmc twice now right on the USA Mexico border.
***"Gettin There"-1973 23' Sequoia-
Michael, Onans smell, "Go solar/wind power!"
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| Re: Muliple Alterators (5) [message #156736 is a reply to message #156731] |
Sat, 14 January 2012 23:44 |
Adrien G.
Messages: 474
Registered: May 2008
Location: Burns Flat, OK 73624
Karma: 1
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Michael,
Unless this is a long involved process, I'm sure John is not the only one interested in the info, I'm also curiously interested (how to control the output of multiple alternators).
Not that I need to do it, but knowledge never gave me a headache like not knowing and having to do it does.
> John wrote "Would you mind please outlining how they are wired and controlled.especially if one is using 5 or 6 alternators."
> Michael wrote "I'd be glad to assist. If you email me I'll Find out what system your wanting to run."
Curiosity killed the cat, but satisfaction brought him back.
Adrien & Jenny Genesoto
75 Glenbrook (26-3) Mods LS3.70 FD / Reaction Sys / 80mm Front&Intermidiate / Hydroboost / 16" Tires / Frame Rebuild / Interior Rebuild
Yuba City,Ca. Text 530-nine-3-three-3-nine-nine-6
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| Re: Muliple Alterators (5) [message #156767 is a reply to message #156736] |
Sun, 15 January 2012 09:37 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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I have flown several multi-engine airplanes with their corresponding multiple / identical alternators. There are several ways they control / run them but usually each alternator can be put on line separately or both together. There is usually a CB in the field circuit that you can pull to shut one or the other down. Also some have an over voltage trigger that will shut one down in the event of an alternator voltage runaway.
If both are on line at the same time, yes one will start to absorb the load first but as it does the voltage will drop slightly and then some of the load is then shared with the second one. I have had a single alternator fail in flight so all of the load was on the other. It is no big deal because you do not need the full capacity of two alternators.
On one aircraft I flew that had two ammeters you could easily see which one was pulling the load. Usually they were similar in flight. On the ground with both alternator on, I have run up one engine and then the other. With all of the radios and lights, Pitot heat, etc. on to provide a decent load, you could see the load switching between the two.
Keep in mind the above dual alternator system above is more for redundancy than providing capacity in excess of one alternator's capacity.
My point on all of this is just put both of them on line and see what you have.
I do not know how larger airplanes with more than 2 engines like the C-130s Colonel Ken use to fly handle electrical load management. Maybe Ken H. will chime in here.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] Muliple Alterators (5) [message #156788 is a reply to message #156767] |
Sun, 15 January 2012 11:51 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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It is called a APU or auxillary power unit. Sometimes powered by a fan
blade in the slipstream, sometimes powered by a turbine engine. One source
for most power needs, but I believe that there are redundant systems on the
engines as well. Others with more aircraft experience than I have will be a
better source of info.
Jim Hupy
Salem, OR
78 GMC Royale 403
On Sun, Jan 15, 2012 at 7:37 AM, Ken Burton <n9cv@comcast.net> wrote:
>
>
> I have flown several multi-engine airplanes with their corresponding
> multiple / identical alternators. There are several ways they control /
> run them but usually each alternator can be put on line separately or both
> together. There is usually a CB in the field circuit that you can pull to
> shut one or the other down. Also some have an over voltage trigger that
> will shut one down in the event of an alternator voltage runaway.
>
> If both are on line at the same time, yes one will start to absorb the
> load first but as it does the voltage will drop slightly and then some of
> the load is then shared with the second one. I have had a single
> alternator fail in flight so all of the load was on the other. It is no
> big deal because you do not need the full capacity of two alternators.
>
> On one aircraft I flew that had two ammeters you could easily see which
> one was pulling the load. Usually they were similar in flight. On the
> ground with both alternator on, I have run up one engine and then the
> other. With all of the radios and lights, Pitot heat, etc. on to provide a
> decent load, you could see the load switching between the two.
>
> Keep in mind the above dual alternator system above is more for redundancy
> than providing capacity in excess of one alternator's capacity.
>
> My point on all of this is just put both of them on line and see what you
> have.
>
> I do not know how larger airplanes with more than 2 engines like the
> C-130s Colonel Ken use to fly handle electrical load management. Maybe Ken
> H. will chime in here.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
> _______________________________________________
> GMCnet mailing list
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| Re: [GMCnet] Muliple Alterators (5) [message #156818 is a reply to message #156788] |
Sun, 15 January 2012 17:30 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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Jim,
A generator that is powered by fan blades in the slipstream is called a RAT (Ram Air Turbine). On large commercial airliners they
are for emergency power generation and are deployed when all else fails.
Hamilton Sundstrand (my former employer for 33 years) is the number one large aircraft power generating company in the industry.
Rather than bore everybody with the power generating systems in large aircraft if anyone is really interested just Google Hamilton
Sundstrand and you'll find more info than you'll ever want to know!
As far as turbine powered APU's go the pecking order is Honeywell (Garrett / Air Research), Pratt & Whitney, Hamilton Sundstrand.
There probably are more but I retired in 2001 and lost touch with the industry. Hoolee Doolee I just realized I've been retired for
TEN YEARS already. Time flies when you're having fun! Especially if you own a GMC! ;-)
Regards,
Rob M.
-----Original Message-----
From: James Hupy
It is called a APU or auxillary power unit. Sometimes powered by a fan
blade in the slipstream, sometimes powered by a turbine engine. One source
for most power needs, but I believe that there are redundant systems on the
engines as well. Others with more aircraft experience than I have will be a
better source of info.
Jim
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: Muliple Alterators (5) [message #156870 is a reply to message #156705] |
Sun, 15 January 2012 21:12 |
RadioActiveGMC
Messages: 1020
Registered: November 2010
Location: Hot AZ desert
Karma: 0
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Senior Member |
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True but on forums many times people just love to have a negative opinions. I really love this forum, but there are some people who must lurk not to educate, but to make sure they try to make others feel less then them. I always find it funny when you ask a question and people base their response on nothing that applies to the question. What makes this forum a pleasure if the wealth of people willing to help. I was reading on another forum someone who asked the same thing I did about the Ryobi Generator I just bought. NOBODY owned one, but tons of people said they had to be junk cause they were sold by HD. Some commented about a tool they owned 5 years ago and disliked. 2 pages of useless info, and the guy said he would avoid the product now cause the Ryobi had to be junk. YET NOBODY ever used the product, or even tested it.
But let me say this. Ask one question even on this forum that may be out of the normal thought of the avg forum member. Why do you get so many off the site responses? People telling you they they sent the message off the site when it could be in the eyes of everyone? Same reason I have there are people who simply LOVE to put in their 2 cents.
I want a 200 amp alternator. You get a response You don't need one. Yet there is not even enough info to ever say that. I'd love to tell people about motor 200-600 amp motor mauls (which is the far more modern way of going high amperage), external regulated huge 12v systems. But honestly there is a ton of info on google. If someone has a legit question I'm proud to assist off the site.
To many this or any other forum maybe used for different things. But this site is for GMC motorhomes. Google GMC motorhomes and of course this community comes up. Its a wealth of GMC knowledge. But again disagree with the thoughts of someone who sat in on a seminar about something, and see the responses. Or disagree with a crabby member who is smarter then most people who walk the earth but can't fathom thinking outside the lines or perhaps there is new thoughts on a subject, and see the response.
I've read more negative thoughts on this forum, and gotten positive ones off the site. But I'm sure (whoever is reading this) and I love this forum cause this is a obscure subject, with the worlds most knowledgeable people in the GMC world.
***"Gettin There"-1973 23' Sequoia-
Michael, Onans smell, "Go solar/wind power!"
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| Re: Muliple Alterators (5) [message #156872 is a reply to message #156870] |
Sun, 15 January 2012 21:35 |
A Hamilto
Messages: 4508
Registered: April 2011
Karma: 39
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Senior Member |
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| Mr.RadioActive wrote on Sun, 15 January 2012 21:12 |
True but on forums many times people just love to have a negative opinions. I really love this forum, but there are some people who must lurk not to educate, but to make sure they try to make others feel less then them. I always find it funny when you ask a question and people base their response on nothing that applies to the question. What makes this forum a pleasure if the wealth of people willing to help. I was reading on another forum someone who asked the same thing I did about the Ryobi Generator I just bought. NOBODY owned one, but tons of people said they had to be junk cause they were sold by HD. Some commented about a tool they owned 5 years ago and disliked. 2 pages of useless info, and the guy said he would avoid the product now cause the Ryobi had to be junk. YET NOBODY ever used the product, or even tested it.
But let me say this. Ask one question even on this forum that may be out of the normal thought of the avg forum member. Why do you get so many off the site responses? People telling you they they sent the message off the site when it could be in the eyes of everyone? Same reason I have there are people who simply LOVE to put in their 2 cents.
I want a 200 amp alternator. You get a response You don't need one. Yet there is not even enough info to ever say that. I'd love to tell people about motor 200-600 amp motor mauls (which is the far more modern way of going high amperage), external regulated huge 12v systems. But honestly there is a ton of info on google. If someone has a legit question I'm proud to assist off the site.
To many this or any other forum maybe used for different things. But this site is for GMC motorhomes. Google GMC motorhomes and of course this community comes up. Its a wealth of GMC knowledge. But again disagree with the thoughts of someone who sat in on a seminar about something, and see the responses. Or disagree with a crabby member who is smarter then most people who walk the earth but can't fathom thinking outside the lines or perhaps there is new thoughts on a subject, and see the response.
I've read more negative thoughts on this forum, and gotten positive ones off the site. But I'm sure (whoever is reading this) and I love this forum cause this is a obscure subject, with the worlds most knowledgeable people in the GMC world.
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I have been watching this thread because my GMC has never had dash air conditioning. I don't want to run the Onan (in my case Kohler) while going down the road just to be able to run the roof air conditioner. So I am trying to decide if I want to jump through the hoops to install dash air, or install a (second) high current alternator and a big inverter so I can run the roof air while going down the road.
I don't need to know how to get multiple alternators to play well together, I will just make them independent (the OEM one for the vehicle and the high current one for the "house"). But I might one day be interested in how hard it is to put a 250 - 350 Amp alternator on these Oldsmobile 455 engines. So keep posting your thoughts and successes here.
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| Re: Muliple Alterators (5) [message #156873 is a reply to message #156705] |
Sun, 15 January 2012 21:37 |
RadioActiveGMC
Messages: 1020
Registered: November 2010
Location: Hot AZ desert
Karma: 0
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Senior Member |
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Does your rooftop unit work? My dash AC doesn't work either which is a bummer. But I'm sure running the rooftop with the onan would use tons less fuel and take no power away from the motor.
***"Gettin There"-1973 23' Sequoia-
Michael, Onans smell, "Go solar/wind power!"
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| Re: Muliple Alterators (5) [message #156875 is a reply to message #156873] |
Sun, 15 January 2012 21:56 |
A Hamilto
Messages: 4508
Registered: April 2011
Karma: 39
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| Mr.RadioActive wrote on Sun, 15 January 2012 21:37 |
Does your rooftop unit work? My dash AC doesn't work either which is a bummer. But I'm sure running the rooftop with the onan would use tons less fuel and take no power away from the motor.
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In my case rooftop air will have to be available when camping. So if it doesn't work now, it will before the CFO will go camping with me. Running the Onan to power the roof air would take quite a bit of fuel. Fire up the Onan and the roof air and see how long it takes to expend a gallon of gas and you will know what I am talking about. An A6 can run at least two dash air sized evaporators. But I don't know how much drag a 250A alternator running an inverter (rated at 97% efficiency) running the roof air is going to cause. How much more power will that take than the A6 compressor? Anybody?
[Updated on: Mon, 16 January 2012 11:26] Report message to a moderator |
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| Re: Muliple Alterators (5) [message #156881 is a reply to message #156705] |
Sun, 15 January 2012 22:32 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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| John Heslinga wrote on Sat, 14 January 2012 20:42 |
Aaaahaaa!!!
I knew you wanted to drive some sound or communication electronics!! Not many standard creature comforts in a standard RV would need that much power. For curiosity sake, I've tried finding how to control all of those alternators and how to wire them up but have not been able to.
Finally: someone who knows. Looks like your the expert I've been looking for. I have a lot of questions but these two would give clues to their answers.
I know that some installations are simply twin, isolated systems but once you get into 3 or more alternators they aren't
Question 1
My thoughts are that each internal regulator would not be exactly the same and wiring resistances to each regulator would mean that the field coils would not energize exactly the same. That would mean that the output voltage of some would be slightly different. That difference would mean that the higher output voltage alternators would disable the lower voltage alternator resulting in unequal loading of each alternator and your total available current would not be as expected. Do you only use one regulator with a sense wire to the system that controls all field windings? And is the output of each alternator simply hooked to each other and the battery?
Question 2
As long as the battery will maintain system voltage there would be no problem. (good battery) But given that a battery needing charging will just about take all the current a charging system is able to give until it's voltage is high enough. ( the regulator only controls voltage) (especially if it is close to dead or with a dead cell). Would the high current want to boil the batteries (or maybe fry is a better word).
Would you mind please outlining how they are wired and controlled.especially if one is using 5 or 6 alternators.
BTW. I cannot see myself ever doing this to my GMC , but I know of a few people who want to shake the windows of 20 cars on either side of them.
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Several years back, I did set up an owner's boat (Twin screw power - I do work on them when rarely but I try not to let anybody see me) with a second alternator on each main engine. The final result was a boat with three separate DC systems - as our coaches have two, but we only have one main engine. (Actually, those with a separate APU start battery really have three also.) The system supplied house lights and all the normal stuff, but there were also two massive inverter/chargers such that the system could start and run the A/C even with the microwave, electric cook top and waterheater from the house bank. And, he wanted to be able to charge the house bank with less than three hours at cruise. There was an APU on board, but wife did not like to hear it running.
To get the system designed, I leaned heavily on a person at Balmar. We added mounts and belts to both mains, and the high output alternators were configured to be really spinning at cruise. The Balmar engineer (I can't find my notes just now for his name) pointed me at the instructions to connect and program the two required regulators so they would both carry (or nearly so) the same load and both limit at their capability. fortunately, the engines have to run within a very few RPM of each other. And yes, the system could recover four each 8D that were seriously drained in the three hours to run across the lake. So, what you want to do is possible, but it won't be cheap.
The system did work and it is south now so I can't tell you anymore.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: [GMCnet] Muliple Alterators (5) [message #156961 is a reply to message #156953] |
Mon, 16 January 2012 15:57 |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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| Greg and April wrote on Mon, 16 January 2012 15:48 |
Don't some APU's circulate warm anti-freeze through an engine making it easier to start when cold?
Greg H.
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Let's try this again...
This is not an uncommon thing in some cold climate small marine power plants and is now very common in OTR(Over The Road aka Long Haul) trucks.
In case you don't know, OTR drivers are very restricted as to how many hours they can drive and how many days in a row they can drive at all (a simplification). So, they stop a lot and sometimes for a long time. To deal with this many sleepers now have a galley, a head and internet. Many locations now have rules that prohibit idling trucks for long periods. To make the sleeper usable for long periods, they have a little teeny tiny mini micro diesel APU. (It lives in a box at the end of one fuel tank.) As it is often connected to the main engine's cooling system, it does accomplish this as well as providing the sleeper with it's requirements.
The marine versions were never that nice.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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