Information on an Air Force EMU-10/U generator

[bmwsyc]

I just picked up the above mentioned generator and am looking for information. I found a manual for the Wisconsin V-4 engine, but I would love to get the manual for the generator itself. I have done a bit of searching already, but have come up empty handed. What I can tell so far is that it is a 10kw gasoline generator, running at 1800 rpm. The NSN is 6115-00-719-6122. The gen set looks pretty sophisticated for a 1968 vintage and looks to be in decent shape.

If anyone could point me in a direction, it would be greatly appreciated.

Photos as soon as I get it off the trailer.

Thanks.

 

[bmwsyc]

Pics...

Still a mess fro the pickup...checked a few things over and oil seems to have been recently changed...added two batteries and it started right up...but voltage output is about 39 volts, should be 120 at the panel.

Muffler is shot, and some of the gauges don't seem to be working.

The Generator originally came with an electric and fuel fired heater for the oil sump...the fuel fired one looks to be gone, but the electric elements still seem to be there.

It looks like you can hook up utility power and it will autostart when the utility power drops below a setpoint. It also looks like the set has the option to parallel with another set.

I'm guessing that something is up with the voltage regulator as to the 39 volts out...the voltage adjust knob does nothing, but it does ohm out good.

Without a manual, it will be a little harder to troubleshoot.

 

[Jimc]

haha the only thing that looks familiar to me on that thing is the facet fuel pump. thats thing is older than me. sorry i am of no help

 

[bmwsyc]

Here is a question, in the simplest sense, can you mate something like a sx 460 voltage regulator to a bare generator head and have it work? I have to do a little more reading, but if the generator head has rotating diodes built into the head, you should basically only need the aftermarket AVR to create a stable output....assuming good engine governing.

 

[steelypip]

That sounds probably true. It's worth looking into getting the stock VR fixed, though - it's probably very simple electronically speaking because this unit falls in just the right age range: new enough to be transistorized, but not so new that everything is a potted, unrepairable custom IC.

I'd be curious to know how the auto cutover circuit works on something this old. It's a heck of a nice feature to have if you can get it working.

 

[bmwsyc]

I did get it running. One of the terminal strips uses 6-32 brass machine screws and because of time or vibration or corrosion or by mouse saliva, some of the heads popped off...I found one early on and yesterday while tracing the generator head wiring, I found two more...one of them being a field coil lead...fired it up, a few seconds later, the field built up and I had juice. I did a mini load test of a 4500 watt heating element...seemed to work fine. Definitely notice when the load is applied, more so than with my 002a.

Discovering more things every time I putz with the set:

Battery charging is done my the generator, not the engine.
In addition to the oil sump heaters (gas or electric) there are electric strip heaters and a basic control in the battery box.
Electric governor and electric choke.
No load side overcurrent protection as far as I can tell. Overspeed, overvoltage, overfrequency, and overtemp protection, but not overcurrent.


I think the auto start circuit starts the engine when utility power drop below a preset level, but frequency control is done with a knob, and the load contactor also has to be manually engaged. Don't know why it would start on it's own when someone has to be there to connect the load. The frequency knob has a "start/idle" setting which I think enables the electric choke...so if you leave it set for 60hz, it may be hard starting when cold.

I ordered a new muffler off of e-bay...ironically an exact replacement for $20.00 plus shipping and I need to dig into the oil and cylinder head temp gauges to see why they are not working...I also want to clean out debris (old mouse nests) and such before firing it up again. I also picked up oil, just to have piece of mind of an oil change. I'd also like to dig into where the set gets power for the heaters and see if battery charging can be done when the set is not running...I would kinda assume that heaters would run off of "plug-in" power and not the batteries.

 

[steelypip]

So there was a separate automatic transfer switch as part of the installation. That actually makes sense. The auto transfer switch would wait for good power from the gen set before switching from utility to generator power. I suspect you're right about the heaters all working off utility current. They're there to keep the genset hot and ready all the time, not to preheat before use. Either they were turned on and off manually by an attendant according to crankcase temperature, or there's a thermostatic switch somewhere. I suspect it's like our diesel MEPs - you can pre-set the governor pretty close and have the thing start up and carry load without needing another adjustment.

Battery charging done by the genset also makes sense - there would be a maintainer circuit for the genset batteries when connected to utility power anyway, so why not just switch from utility power to gen head power for the charger when the gen set is running?