[Milsurplus] Re: Generators...

[Robert W. Downs]

Ken & Group,

>Good. So what was the 2.5 KVA 110 VAC generator which was a =

10 HP single cylinder aircooled rope-start engine driving, via dual =

belts, its associated 2.5 KVA generator? Practically ubiquitous. =

Excellent generator. The gas-engine used a pre-combustion =

chamber in its head, which is somewhat unusual today. Is that the =

PE-75?
<
Oops.  I did mean to mention this one and sent the message without doing
so.  Yes, that would be the PE-75, last model of which was the PE-75-AF, =
I
think.  Used for all sorts of things, TTY sets, some radio sets (SCR-624
for example), telephone centrals, etc.

>Then there was another one I had which was a 4 cylinder gasoline =

engine with a recoil starter on the generator end and an impulse =

mag. Used positive rotation valves and ran at a steady 3600 RPM. =

It was a real gas hog. Put out, via a frame mounted switch, any of 4 =

voltage/phase/currents at 5 KW. 110 VAC single phase, 110VAC 3 =

phase, 220 vac single phase and 208 vac 3 phase.

It was very reliable, although somewhat hard starting, and, as I said =

above a TERRIBLE gas hog at 3600 RPM. One Field Day when we =

used both it and the PU-286-G (1800 RPM), over the same period =

of time, and nearly identical loads, the PU-286-G used 1/4 as much =

fuel as the "hot-rod", 5 gallons to 20 gallons.
<
Don't recognize this one, although I may well have a TM for it.  3600 RPM=

generator sets are typically 2/3 to 1/2 the weight of comparable 1800 RPM=

ones, produce 2 to 3 times as much noise and burn more fuel (4X surprises=

me, though).  An engine running at twice the RPM will produce almost twic=
e
the horsepower as at the lower speed, so the engine can be smaller and
lighter.  But the noise level, fuel consumption and exhaust gas
temperatures all go up.  TANSTAAFL.  Most of the light duty light plants
sold today are 3600 RPM plants.  The engines cost less per KVA than 1800
RPM ones.  Don't last nearly as long, either.  The generators are also mu=
ch
lighter, but that's due more to improvements in technology (alternators,
for example, rather than traditional AC generators) than to cheaper
construction, I think.  I have a 4.4KVA behind the garage that doesn't
weigh very much more than my PE-214-C (300VA).  But if it weren't behind
the garage, you couldn't carry on a conversation in the house.  :-)

73
Robert Downs
<RWDowns_WA5CAB@compuserve.com>
Houston