high output and efficiency alternator

[mobile_bob]

For those that are interested i finally finished a published the white paper on the research that i have done
on the reapplication of an automotive alternator for a specific use.

anyone interested in driving an automotive style alternator with a small diesel engine at higher voltages
might well find this information interesting.

if interested the paper can be found in our "white papers" board as an attachment

comments welcome

bob g

[Dail R H]

   Bob,
   I'd been sorta following your progress. I'm thinking of maybe a 48 volt battery system with appropiate converters. Just haddn't got that far yet. (engine is still sitting on shipping pallet,sigh)

[EBI-WPO]

Mobile Bob,

Thanks for sharing. Informative as usual.

Terry

[WGB]

Thanks Bob.

[mobile_bob]

thanks for the kind words fella's

as most that have been following my testing, i am working on a much higher power version
for the 48volt battery applications.

if i can just get my back issues sorted out, maybe i can get back to it sooner than later.

currently i am stalled in testing at about the 80amp output at 57.6 volts, my target is for 130-150 at 57.6
and i really think i can get there, whats holding me back has nothing to do with the design of the alternator
i just have to change the drive ratio a tad bit and i just haven't felt like doing it lately.

the upside is i have given some serious thought to incorporating switchgear to change the stator from
delta to wye connection, changing from delta to wye limits my current to about 57% of what it will do
connected as delta, but i can reduce the engine speed by the same factor and do the absorption charge
regime where i don't need the full 130-150amps  (57% of 130-150 is about 74-85amps which is very good anyway
at an average of ~ 4.6kwatts)

dropping the rpm from 1800 by the factor of 57% works out to a touch over 1000rpm, which is slower than
the engine runs well at anyway, so i will probably drop to a more suitable 1200rpm and pickup the gains in reduced
fuel consumption.

between the two (reapplied alternator/reconfigured stator and reduced engine speed) it should put me close to parity
with the st head, in that i can produce power and feed it to a pure sine wave inverter to make AC power of superior
quality, (very low distortion, stable hz, stable voltage) and attain the same BSFC in gr/kw/hrs.

when i started down this path i would have bet against my being able to get even close, however now i would not bet
against me, most especially my lunch money.  i think the odds have shifted into my favor on this one.

then lastly is the change in prime mover from the idi engine to the di engine, the di is reported to be approx 3-5%
better in fuel consumption over the idi engine i am currently testing with. if that is the case, this system powered by
a DI engine will be the most efficient producer of pure sine wave that burns diesel that i know of anywhere, (in the
5-8kwatt class, that is priced under 20 grand).

i am really thankful to Quinn for having posted a link some time ago, on the LEF from victron energy where they
did independant testing of commercially available diesel engine gensets, their test results provided the info that illustrated
the range of relative overall efficiency of those units tested in gr/kw/hr for each of 3 classes. Armed with that info one
can determine how close he is and then set out to see if he can play with the big boys in their ballpark. what i am finding
out is yes we can not only play in the game, but not just warm the bench or be bat boys.

man i got to get healthy again!!

bob g

[WGB]

thanks for the kind words fella's

as most that have been following my testing, i am working on a much higher power version
for the 48volt battery applications.

if i can just get my back issues sorted out, maybe i can get back to it sooner than later.

currently i am stalled in testing at about the 80amp output at 57.6 volts, my target is for 130-150 at 57.6
and i really think i can get there, whats holding me back has nothing to do with the design of the alternator
i just have to change the drive ratio a tad bit and i just haven't felt like doing it lately.

the upside is i have given some serious thought to incorporating switchgear to change the stator from
delta to wye connection, changing from delta to wye limits my current to about 57% of what it will do
connected as delta, but i can reduce the engine speed by the same factor and do the absorption charge
regime where i don't need the full 130-150amps  (57% of 130-150 is about 74-85amps which is very good anyway
at an average of ~ 4.6kwatts)

dropping the rpm from 1800 by the factor of 57% works out to a touch over 1000rpm, which is slower than
the engine runs well at anyway, so i will probably drop to a more suitable 1200rpm and pickup the gains in reduced
fuel consumption.

between the two (reapplied alternator/reconfigured stator and reduced engine speed) it should put me close to parity
with the st head, in that i can produce power and feed it to a pure sine wave inverter to make AC power of superior
quality, (very low distortion, stable hz, stable voltage) and attain the same BSFC in gr/kw/hrs.

when i started down this path i would have bet against my being able to get even close, however now i would not bet
against me, most especially my lunch money.  i think the odds have shifted into my favor on this one.

then lastly is the change in prime mover from the idi engine to the di engine, the di is reported to be approx 3-5%
better in fuel consumption over the idi engine i am currently testing with. if that is the case, this system powered by
a DI engine will be the most efficient producer of pure sine wave that burns diesel that i know of anywhere, (in the
5-8kwatt class, that is priced under 20 grand).

i am really thankful to Quinn for having posted a link some time ago, on the LEF from victron energy where they
did independant testing of commercially available diesel engine gensets, their test results provided the info that illustrated
the range of relative overall efficiency of those units tested in gr/kw/hr for each of 3 classes. Armed with that info one
can determine how close he is and then set out to see if he can play with the big boys in their ballpark. what i am finding
out is yes we can not only play in the game, but not just warm the bench or be bat boys.

man i got to get healthy again!!

bob g

That would be great!
Thats the voltage I would need plus as many amps as possible.
How many board members are using 48 V bank I wonder.
Health issues are a pain no pun intended.
I think of all the projects I have going, 50 acres, going off grid, two new buildings and all, too little too late. Hate to put the wife in that situation, but she is on board with it all.
Sorry for the drift.

[mobile_bob]

i might well have quit at 24 volts had it not been that i came up with about 30kwatts of 48volt buss exeltech inverter system
i already had so much high grade stuff geared toward the use of 24volts, so it was a hard decision to move up to 48volts.

once i get this sorted all out to my satisfaction i will have a ton of really cool stuff for anyone that is running a 24volt system
for sale to anyone that can use it.

things like 300 and 400amp 24vdc coil  DC contactors, these are new old stock and are monsters,
propane 6kwatt backup generators from a local telecom installation, very low hours, unless i can convert
them for 48volts the three i have might be better off in new homes.

thats the problem for not thinking things through very well before you start collecting bits and pieces,, you end up
buying literally tons of stuff that you end up not needing.

in my defense, i just never figured that i would be able to ever get an exeltech inverter system and would have to settle
for something less, in which case it would have been something that fit in with the 24volt buss.

its just too bad the refrigerator manufactures haven't made the move up from 12/24 to 48volts as of yet, maybe before i am
ready they will have done so.

maybe if i can get the relative overall efficiency up high enough, i can just use standard AC powered refrigerator on my system
and be close to parity in efficiency to what a 48volt DC refrigerator could or would be?

i guess we shall see the close the time comes to needing one.

bob g

[WGB]

i might well have quit at 24 volts had it not been that i came up with about 30kwatts of 48volt buss exeltech inverter system
i already had so much high grade stuff geared toward the use of 24volts, so it was a hard decision to move up to 48volts.

once i get this sorted all out to my satisfaction i will have a ton of really cool stuff for anyone that is running a 24volt system
for sale to anyone that can use it.

things like 300 and 400amp 24vdc coil  DC contactors, these are new old stock and are monsters,
propane 6kwatt backup generators from a local telecom installation, very low hours, unless i can convert
them for 48volts the three i have might be better off in new homes.

thats the problem for not thinking things through very well before you start collecting bits and pieces,, you end up
buying literally tons of stuff that you end up not needing.

in my defense, i just never figured that i would be able to ever get an exeltech inverter system and would have to settle
for something less, in which case it would have been something that fit in with the 24volt buss.

its just too bad the refrigerator manufactures haven't made the move up from 12/24 to 48volts as of yet, maybe before i am
ready they will have done so.

maybe if i can get the relative overall efficiency up high enough, i can just use standard AC powered refrigerator on my system
and be close to parity in efficiency to what a 48volt DC refrigerator could or would be?

i guess we shall see the close the time comes to needing one.

bob g

Run two a 24 volt freezer and 24 Volt refrigerator in parallel  LOL
I have been running a 277 v heat pump, one hot one neutral as you know, on 240 v for 20 years!

[BioDBilly]

Hi Bob!

First of all, Thanks for sharing all the hard work.  (And I hope your back is doing better!)

I read your white paper with great interest.  I am nowhere near qualified to contribute on electrical engineering but as a semi pro DIYer, I'm gettin fired up over your success. I'm implementing a number of off grid systems.  While I think there is great merit in a KISS system under certain conditions, the one I'm likely to want to live with is yours.

I'm curious about the prime mover applications that would be possible, essentially, the HP and torque requirements that the Prestolite would demand.  Joel K first suggested that I put an alternator on the little 4HP engine he sold me.  It seemed to make sense for a bunkhouse system on the ranch.  A golf cart starter/generator could provide the 12v leg, perhaps even on a 6/1.  I'm also speculating whether to dedicate the shop Redstone to 240v with an ST head and leave the 120v to a Mobile_Bob Prestolite/sine wave inverter system.  (This unit is the basis of a multifunction platform that will include a flour mill and 2-3 ton oilseed press, maybe more).  It looks like your system would suit a number of applications, from 24v on up.

Again, Thanks for all the hard work, I'll be following along with great interest!

[Jedon]

How many board members are using 48 V bank I wonder.

*waves* me!

I am eagerly awaiting the day I can hook up one of these bobinators to my 6/1 to feed my 16 L16's and my Xantrex inverters.

[mobile_bob]

Bio and others:

thanks for the comments and interest

as for the KISS principle, i jab a lot of folks the wrong way on that one so maybe i should take this
as an opportunity to get on the record on "KISS"

KISS can be a very good thing and should be the basis of any and all offgrid systems, in so far
as it relates to being a part of a larger system.

for example,
the 6/1 and driving an st5 has been proven by many as being able to deliver power of adequate quality
for many thousands of hours, and in some cases a few tens of thousands of hours with some repairs
and rebuilding along the way,, not bad, certainly KISS in it purest form for anyone using an engine driven
genset.  the only way i can see to improve on that substantially would be in favor of a pm head from George
in favor over the st head, (no brushes, rectifier and all that)

so now you have your KISS power plant, and all is good, except
you either learn to adapt to life with it running 8,16, or maybe 24 hours per day, and
you might find that it is not the most efficient producer of kwatts based on the fuel consumed

now this might not be an issue for those with an inexhaustible source of alternate fuel stocks, such as waste veggie
light motor/tranny oils etc, and maybe not much of an issue for those that can afford pump diesel sans the road tax,

however fuel efficiency will become a major concern at some point in the future when faced with having to use only
pump diesel at some astronomical price, we have seen 5 dollar diesel out here in the pacific nw last year, if it went there
once it will surely do it again.

but i digress

my contention is anyone offgrid should have various forms of power production, and not rely on any single source
as their sole source of power.  this is where i think the hydrid system (aka inverter/generator) system makes sense
one designs and builds the unit, perfects it and uses it as it makes most sense on a fuel consumptions efficiency basis.

of course the system is more complex, and quite frankly it might be very complex compared to a basic 6/1 driving
a pm head, but lets face it an original lister startomatic must have been seen as bleeding edge technology to folks
back in the day. obviously the startomatic proved itself to be very reliable  and in the long run a nice trade off in
KISS and technology.

can there be any doubt that lister would have built an inverter generator had the inverter technology been what it is today?

as for you 4hp diesel prime mover, that works out to about 3kwatts mechanical, and with an efficient drive a 110-555jho
driven and controlled to provide 24volt nominal should get you close to ~2.3 kwatts output, fed to a battery bank sized appropriately
to the charging source of about 375amp/hr (give or take, it could be somewhat larger with longer run times) you could end up
with a fairly efficient system that would have a continous output rating of perhaps 1.8kwatt AC and a surge up to many times that
level depending on the capacity of the inverter you choose to run.

having not worked with a 4 hp i am not sure how it would stack up in practice compared to a 6/1 listeroid in fuel efficiency
it might be that the edge would still go to the 6/1 driving the st or a pm head, but the 6/1 has to run all the time where
the 4hp inverter/generator might be applied to where it has significantly less run time, so in the end analysis even though
it burns more in a heads up competition, it edges out the 6/1 in practice.

one thing for sure is the surge capacity will be higher, the frequency will be dead on accurate, no flicker, accurate voltage
regulation and much lower distortion depending on quality of inverter used.

basically i am a proponent of having the KISS genset, you must have a fall back position
once that is in place and has proven to be reliable, then the second unit can adopt a bit less KISS in my opinion
and depending on ones abilities perhaps something far from KISS can be designed and built that has a very
much higher efficiency as compared to the KISS unit.

bob g

[mike90045]

Is your 48V alternator & coarse regulator any more complex than an ST with a dieing doghouse ?

(I'd feed a normal charge controller for the final charge for batteries )


65V @ 3KW = 46A   Awesome!
 
How many RPM does the alternator need to have it's "fan" become effective? i'd always thought about 6,000-7,000  with the small pulley and
nominal engine RPM in a car being 3K ??

[mobile_bob]

Mike:

not sure if i understand your questions but will try to answer anyway

"Is your 48V alternator & coarse regulator any more complex than an ST with a dieing doghouse ?"

yes and no, more complex in that there will be the seperation of excitation, seperate regulator and attendant
connections, basic operation internally is the same

"(I'd feed a normal charge controller for the final charge for batteries )"

yes you could use an outback mx60 "if" you rectify and stabilize the st head output to a fairly clean dc and keep
it below the (iirc) 140vc upper limit, which means you will likely need to decrease the st head voltage by some means

"65V @ 3KW = 46A   Awesome!"

yes that is good, but   57.6 @ 130amps = 7.49KW is "awsomer" 

(and the efficiency will be higher than using an st head feeding the mx60 overall.)

actually the mx60 should convert better and give more than 46amps, you should get
closer to 70amps i would expect.

"How many RPM does the alternator need to have it's "fan" become effective? i'd always thought about 6,000-7,000  with the small pulley and nominal engine RPM in a car being 3K ??"

first of all we are not talking about a car alternator, rather a large frame truck alternator, where in the project X alternator cuts
in at about 1200rpm in its oem application and produces well over 150amps at 2200rpm (alternator speed) the fan is matched for this operation,  however the fans ability to cool is of secondary concern due to the following

1. because this is a reapplication of an oem design for higher voltage output it must be turned faster, the speed needed for this
specific alternator is approx 6500rpm to attain the design goals of this application, and

2. the fan follow the cube law, wherein if you double the speed you get 8 times the airflow (according to theory, reality is a bit less
than 8 times.) and

3. the efficiency of the alternator is markedly higher, higher efficiency equates to less heat generation, which is the principle product of
inefficiency or losses of any alternator.

what i am proposing is an alternative that is efficient, cost effective, of good design, using off the shelf components, that will allow for
programmable control of the charging regime of a battery installation, along with having temp sensing for alternator protection and for temp compensation of the charge rate, and do it at a higher output than is typically available by other means.

bob g

[XYZER]

110-555JHO information? Does anyone know the key size used on the .875 pulley shaft? The spec sheet I have gives all of the dimensions but the key width. I am ready to cut the keyway in my pulley but don't have my cheat sheet with me and my memory is ...well faulty now days....5/32" seems to ring a bell. It will be a couple of days untill I have my hands back on the alternator.....thanks and hope I didn't wander to far off topic....

[admin]

Dave:

i am almost positive it is an 1/8" keyway

i would have to check, and can get back to you later today.

however many of the alternators don't use the key, they simply
rely on the compression fit afforded by the retaining nut on the end of the shaft.

admin