[Milsurplus] Mil generator

[Kenneth G. Gordon]

> It is actually a 5kw

OK. Is it under a sheetmetal shroud, with a lift-up lid?

> 
> 120/203 3-phase 4 wire

This should be 120/208 3 phase 4 wire, not 203.

> 
> 120        1-phase 2 wire

OK.

> 
> 120/240 3-phase 3 wire

This should be 1 phase, not 3 if it is 3 wire. A 3 phase delta, 
configuration would be 3 wire, but this is not normally done except for 
transformer distribution systems.

Ordinarly, for all the generators I have seen, if the output is 120/208 
VAC, 3 phase then it would be in a so-called "star" configuration with 
the neutral coming out of the center of the star, so you would have 4 
wires.

In any case, there is really no way you can get 120 VAC on any one 
phase, and then have a full 240 VAC between any two phases. 
Because of the phase differences, the total voltage is always 208 VAC 
in that case, but you already HAVE that as one of the outputs: the first 
one you listed.

Therefore, it is single phase, 120/240 VAC 60 Hz. 5 KW output at that 
position. This is the most suitable for a home or shack.

BTW, the voltage change switch on mine was back under the control 
panel. It had a largeish black bakelite knob that took some effort to 
switch.

> 
> 120        3-phase 3 wire

OK. Mine was this way too.

> 
> Sec mil-g-12373 (ce)
> 
> generator set  skid mounted  
> 
> 5kw, 0.8 p.f., 60 cycle
> 
> po# 88f-3983-(27)-29
> 
> dated 6-13-55
> 
> stock list sml (scratch here...not sure if something should be here) it-4780 (scratch 
> could be a 7 or comma) 525-250
> 
> made by John R. Hollingsworth
> 
> model ea536

This number is the important one. It describes both the manufacturer 
and the model. Documentation is still available for this, both for the 
engine and the alternator.

This generator sounds almost exactly like one I had. If it is, the engine 
turns at 3600 RPM.

Does yours have a recoil, rope-pull starter system on the panel end? 
There was an optional electric start, but mine didn't have it.

That would just about clinch it.

They also have an Impulse magneto.

Further, the fan blows OUT through the radiator, and there was a 
handle on the shroud to enable you to regulate the air flow through it by 
means of louvers.

The genny was designed to be installed inside a building, hooked to the 
hot air heating system and heat the building in which it was mounted.

The gas feed for it was to a fuel pump via a 25' neoprene fuel line that 
had an adapter on the end to literally "plug into" a 5 gallon Jerry can. 
There orginally was no real fuel tank mounted anywhere on it.

The engine, if yours is the same as mine, had Stellite valves, and a 
positive rotation system for them.

I STILL insist that it would be least expensive for you to take it to a 
technical school, mechanics school, or mechanical engineering school 
to get it rebuilt.

My genny was extremely reliable, despite the 3600 RPM speed, but 
drank gas like crazy.

I had another 5KW genny, a PU-286/G, that had a 4 pole alternator, 
and turned at 1800 RPM, and it used less than 1/2 the gasoline that my 
high-speed one did under the exact same load for the same length of 
time. This was during a Field Day back in the 1960s or so. We had 10 
stations set up.

The PU-286/G was 120 VAC single-phase only though. It was originally 
part of a field radar set, and I got it through MARS.

The genny you have is both extremely versatile, and very reliable. It is 
well worth trying to save, IMHO.

Attempting to couple a different engine to it would result in many 
headaches trying to mate and configure the governor system.

BTW, what city are you near? My gennys were in Missoula, Montana. I 
don't have either one now.

Ken Gordon W7EKB