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Messages - 90cummins

#1
Mep-952b Test


9/21/2015
I purchased this unit awhile back to provide an additional support system for my emergency battery backup system.
It was built for the Military to provide 180 amps at 28v DC power (5kw) for the US Army's Tracked Armored Command Center so the main engine does not need to be idled.
It has a German Farymann 43F diesel engine rated at 15hp @ 3000rpm and drives a Niehoff alternator rated at 280 amps @ 28v.
I chose unit because it is fully enclosed (quiet) and has low oil pressure and over temp shutdowns.
It can be set up for remote operation and being DC I can vary the engine speed to meet my electrical loads for fuel savings.
I have performed fuel consumption tests on all my generators to determine how much fuel I need on hand for a day, week or month long outage.
Thru this testing I know which generator to put into service depending on my needs.
This is my second test on this unit and the results are encouraging.
My first test on 7/1/2015 was performed with this generator as I received it. It was running at full rated speed which was advertised as being 3000rpm.
The first test at full speed gave me run time of 2.67 hours per gallon with a 1kw AC load.
I then modified the governor system to allow a high and low speed setting so another test was needed.
That brings us to today.
The changes I made allow the engine to run at 3000rpm or at a reduced speed of 2550 rpm no load and 2342rpm with a load of 1.8kw.
I used an optical tachometer for checking the rpm during the test.
My test procedure is as follows;
I connected the APU to my whole house inverter and switched over to my 24v battery back-up system.
I used a portable heater to create a stable load which in this case was 1.8kw's.
I started the engine and applied the load and allowed the engine to stabilize for several minutes before starting the test.
I then recorded the following;
Time, Engine rpm, AC kw's, DC Kw's, Fuel consumed in Oz's
I started the test at 30 ounces and recorded various data points as the fuel was consumed.
I stopped the test when there was 6 ounces left.
24 ounces of fuel were consumed in 39 minutes with an average load of 1.8kw's.
I was pleased with today's results which were much better with a run time 3.47 hours per gallons with the engine running at 2342 rpm and a 1.8kw AC load versus 2.67 hours with a 1kw load.
I will continue to tweek things and perhaps make a variable speed controller that will respond like the Honda EU series inverter generators.
90cummins


#2
I have 2 Military Surplus MEP-952b 28 volt DC APU's rated 5.5kw that were used to power the M1068 tracked command center.
My plan is to use them to support my 28v whole house battery backup system.
Very nice German air cooled engines rated 15hp @ 3000rpm. They can be easily started with a hand crank if needed. Fully enclosed, quiet & armored.
The alternator is a Niehoff  N1379-1 rated at 280A.
Currently working on a two speed throttle control system that will allow operation at 3000 or 1800~2000 rpm to reduce fuel consumption depending on load.
Will post pictures when I get the new throttle control installed.
90cummins

#3
General Discussion / Re: Power Outage
September 03, 2015, 05:32:40 AM
Quote from: Carlb on June 27, 2015, 12:52:06 PM
We had some very high straight line winds come through here on early Tuesday evening and a tornado warning (doesn't happen here in southern new jersey often) and it took out a lot of trees and power lines.  My neighbors trampoline who is about 400 yards away went through his vinyl fence and ended up in my back yard wedged against a large tree.   When I saw that I quickly got a large piece of rope and tied it to the tree so it wouldn't go any further.

Power went out at around 6pm on Tuesday and they didn't restore power until around noon Friday.  I am pleased to say that the Listeroid performed flawlessly averaging 14to 16 hours straight per day average load was only about 1700 to 1800 watts. 

My listeroid is a hybrid using diesel for pilot ignition and natural gas.   In the aproximatly 45 to 50 hours of run time it only used a little over three gallons of diesel,  I have no idea how much natural gas it used but who cares I didn't have to go find a open gas station that sold diesel since i normally keep 15 to 20 gallons on hand.

Hi Carlb;
Your listeroid's performance no doubt moved you up to Hero Status!
I recently built a 28v DC generator using a Yanmar L100 running at 2750 rpm driving a Niehoff N1603-2 Military Surplus alternator. Recent fuel consumption tests I performed gave me a 5 hour per gallon run time while supporting the entire house in a simulated winter environment.
The electrical load included running the heat, 1 fridge and 2 small chest freezers and the deep well pump operating while watering the garden.
While this is good I'm looking for more.
You posted this in June so you have received your gas bill by now, could you follow up and calculate the natural gas consumed to determine the cost/hour??
Do you know how much diesel it would take to operate 24 hours?? 
Thanks
90cummins (new guy)