Any "Off-the-shelf" 48 volt alternators?

[LincTex]

Are there any "Off-the-shelf" 48 volt alternators available?

Or is this something I need to have custom wound?

Can a 24 volt alternator be "pushed higher" to 48 volts with the right regulator?

[glort]

Can a 24 volt alternator be "pushed higher" to 48 volts with the right regulator?

Yes.

I think it was Mobile Bob here wrote an excellent paper on using external Regulators  on Leece alts to give 48V with very high efficiency.
I can't find it now but just doing a search on 48V alternators brings up a massive amount of info that is stored here.  Do a search and you'll find more info than you can Imagine.

Maybe someone else can find the paper and the work bob did on these. I'd like to download the paper again to make sure I still have it.  I always keep an eye out for the Higher amp Leece 24V alts but they always go for a fortune here and shipping from the US is just plain Robbery as it is with everything else.
Recently Bought a starter motor off Fleabay for my mower.  Postage from the US, $130 . Postage from Canada, $34.  Kicker was the seller was the same on both sites!

I'd also like to know if it is possible to download all the info on this site.  I know it would be huge but so is the amount of data I generate every year in Photographs I do .
If there were a way to download the whole archives of this site to make sure I had the amazing and somewhat forgotten resources here, I'd buy a HDD just for the purpose.

[glort]

Found it!

http://www.microcogen.info/index.php?topic=157.msg1359#msg1359

[mobile_bob]

to my knowledge there were two alternators that were built for 48 volt service

both were built on the leece neville jb series

one used an external rectifier/inverter and i think it was navistar that used it on service trucks, emergency vehicles and the like
the other was a 48 volt unit that was built to be used on a scissor man lift, for what purpose i don't know

these two were around back in around '07 or so, but somewhat rare, i have an example of each in my collection

neither of these are what i would call high efficiency units, probably around 50% or so

the 110-555jho which is based as a 12volt unit, can be relatively easily modified to run at 48volt nominal (57.6vdc) by replacing the rectifier diodes with non avalanche 200piv units (press in replacements can be had at any rebuild shop) 

you will also have to replace the regulator, use something like the balmar or one of the many other 3 step programmable regulators that are typically available from the boat guys supply houses.

you will have to sample at 12 volts, or mid string  and provide a separate 12volt supply that is isolated from the 48 volt bank, which shouldn't be a problem

the white paper i wrote all those years ago, still stands, and while it probably could be cleaned up a bit, the info is still good.

in testing i was able to get iirc 75amps at 57.6vdc  thermally stable with efficiency equal to that of an ST7.5 genhead, which is right at 78% efficient in testing.  the alternator as modified can provide 100 amps output at 57.6vdc and be thermally stable, but runs a bit hotter, i saw no need for that amount of power and iirc the efficiency dipped a bit.

to date i am unaware of another alternator that has demonstrated in testing anywhere near the ability of the 110-555jho

with my system, which i have never deployed but still have,  i chose to use 2 of the 110-555jho units.  because they are isolated ground units, i can connect the output in series to get the 48 vdc nominal output, get the 100amps and control the two with one of the balmar controller/regulators.  efficiency is excellent and they run thermally well within the limits of the original design.

iirc the original design of the alternator is for 220F service, underhood in harsh conditions,  my laser temp gun measured around 175 when sampling each diode at its base when ran under the modified service. the stators never got over 125 degree's F.

the rotor field is rated at iirc 7amps and under the modified service use 3.5-3.6 amps at 10vdc, so one controller can handle two such rotors with no trouble.  balmar tech told me that the mx612 can handle 10 amps no problem, so there is enough head room there.

probably more than was asked, but it was free!

bob g