MEP-952b 5kw DC generator fuel consumption test.

[90cummins]

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

[LincTex]

How does it compare (fuel/kw/hr) with your other units?

I have an Alliance APU from a semi-truck with a Kubota EA300 and was planning on doing a similar test as yours.