In addition to traditional items of supply like rations and ammunition, the modern battlefield requires electric power. Signal equipment, weapons systems, computers, lighting, heat and air conditioning, and other needs dictate the use of mobile electric generator sets to supply the tactical unit. To meet the need, specialized military generators, called Mobile Electric Power (MEP), have been developed in a range of sizes and capacities. Mobile Electric Power generators are deployed in large numbers wherever the military is operating.
Lend-Lease anti-aircraft searchlight generator sets, mounted on four-wheel trailers, in a depot in England during WW II. The 800 million candlepower searchlights were supplied with their these 15kW generators, manufactured by General Electric and Sperry, powered by 6 cyl. gasoline engines.
The use of generators in the field started in World War I, primarily for signal equipment, anti-aircraft searchlights, and general lighting of fixed positions. By the time of World War II, more extensive use of radio was joined by electrically driven weapons, radar and other electronics that increased the need for field portable, tactical generators. Portable electric generators were fielded in a range of sizes from 2.5kW up. These generators supplied power wherever needed, for everything from radio centers to field dental clinics. Use of generators continued to proliferate as more and more electric powered equipment was introduced and use of radio communications became standard at all unit levels.
By 1960, and during the Vietnam War, over 2,000 generator makes and models were in use in the U.S. military, an unsustainable support challenge. In 1967 the office of the Project Manager Mobile Electric Power (PM-MEP) was established to manage and improve ruggedized power generators for all the Department of Defense (DoD) services. (PM MEP also manages environmental control units for the Army.)
PM MEP designed, developed and deployed the Military Standard (MIL STD) Family of Generators for DoD, using only 37 models to cover all service requirements for gasoline and diesel sets from 0.5kW man-portable to 920kW prime power generators. Over 90,000 MIL STD generators were procured from industry from 1968 through 1987, utilized successfully in Grenada, Panama, Somalia, Desert Storm, and all other operations of the period. Service by the MIL STD generators continued for decades in Reserves and Guard units.
In the early 1980s, The Marine Corps chose eight generators in five sizes from the DoD MIL STD generators to be maintained for use in support of expeditionary Fleet Marine Force (FMF) operations.
The MEP generator family through several generations starting with the original MIL STD generators. Beginning in 1988, the Tactical Quiet Generators (TQG), versions A and B, were developed to enhance the MIL STD sets to provide:
Greater Mobility, Reliability & Maintainability
Reduced Infrared & Acoustic signatures
Lower Cost Operation on Diesel/JP Fuels
The TQG sets began fielding in 1993. By the mid-2000s, the DoD PM MEP was supporting these standardized systems for Military Mobile Electric Power:
Power Units and Power Plants (PU/PP) (Trailer-mounted generator sets)
Advanced Medium Mobile Power Sources (AMMPS) (5-60kW)
Deployable Power Generation and Distribution System (DPGDS) (840kW)
For example, the versitile MEP-831A diesel TQG delivers 3kW of 120V, single phase two-wire or 120/240V single phase three-wire 60Hz power.
IFOR marked USAF M923A1 5-ton 6x6 Cargo Truck with two MEP generators supplying power to TACP (Tactical Air Control Party), 2 ASOS (Air Support Operations Squadron), Operation Joint Guard, Bosnia, 26 December 1996.
Efforts to have a DoD-wide policy standardizing Mobile Electric Power (MEP) Generating Sources were needed, to constantly resist the introduction of non-standard procurement to meet perceived specialized needs. On 13 April 2004, DoD issued DoD Directive 4120.11 reemphasizing the centralization of Mobile Electric Power under the PM-MEP and mandated the use of standardized units rated from 0.5kW to 750kW to provide 60Hz AC, 400Hz AC and DC current. As before, the Secretary of the Army was designated as the Lead Standardization Activity for FSC 6115, instructed to appoint the PM-MEP to manage all aspects of MEP generating sources.
A 2007 census of military equipment in Iraq identified these TQ generators as most widely deployed, with up to several hundred each in the field:
MEP-831 3kW Diesel Generator Set (Skid mounted)
MEP-802A 5kW Diesel Generator Set (PU-797, NSN 6115-01-332-0741, when mounted on M116A3 trailer)
MEP-803A 10kW Diesel Generator Set (PU-798, NSN 6115-01-319-9032, when mounted on M116A2 trailer)
MEP-804A 15kW Diesel Generator Set (PU-802, NSN 6115-01-317-2138, when mounted on M200A1 trailer)
Also widely used in Iraq is the External APU for M1 Series Tanks, NSN 6115-01-369-7465, a small diesel generator that maintains the tank's batteries when its main engine is not running. Dozens of other generator models were used in smaller quantities.
By 2009, PM MEP provided over 125,000 generators totaling 2.1 gigawatts of power to DoD. On 29 May 2008, the U.S. Army celebrated the delivery of the 20,000th 3kW Tactical Quiet Generator (TQG).
Mobile Power Nomenclature and Models
Many model number formats, prefixes and generator series have been used. For Signal Corps use in WW II, many PE-xxx (Power Equipment) and PU-xxx (Power Unit) generators were standardized, eg, the PE-74 15kW system that originally powered the SCR-270 radar, later powered by the PE-138/139. Another common unit in WW II was the 12.5KVA PE-95 series (made by D.W. Onan & Sons, O'Keefe & Merritt or others), hauled on a Ben Hur K-52 generator trailer or on its own 4-wheel trailer base. Post-war, in addition to the DoD standardized generators, the U.S. Air Force EMU-xx (eg, EMU-19) and MB-xx (eg, MB-17) Ground Electrical Power Supplies were two series of service-specific units, distinct from the MIL STD generators.
Most of the different models in the families of generators were subject to revisions, changes, and upgrades due to technological advances and Environmental Protection Agency (EPA) requirements. Because of the evolving development of generators, there are often several model numbers, National Stock Numbers (NSNs) and Identification Numbers (IDs) for each generator size. The generators may be utilized as stand-alone units or, more commonly, are mounted on trailers singly or in pairs. Each combination is designated by its own nomenclature and NSN so a particular generator may be both a stand-alone unit and a component of one or more systems.
Although other prefixes and patterns of naming models have been in use in the past, the nomenclature relationships in use in the 2000s are:
MEP-xxx Generator Set, stand alone or a component of a power unit or power plant (eg, MEP-016A)
PU-xxx Power Unit, usually Trailer Mounted, with 1 generator (eg, PU-797A)
AN/xxx-xx Power Plant, usually Trailer Mounted, with 2 generators (eg, AN/MJQ-35A)
Federal Supply Class (FSC) 6115, "Generators and Generator Sets, Electrical," is used for most MEP equipment and has been since 1949. Therefore, FSN or NSN identifying numbers will begin with 6115. (See U.S. Government National Stock Number (NSN).) Similarly, technical manuals will typically be in the TM 11 series (Signal). Older manuals will be in a form like "TM 11-904" (for the PE-95K generator) while the newer format will usually reflect the FSC in the numbering (eg, TM 5-6115-465-12 for Gen Set, DED, 30 kW, MEP-005A, MEP-104A, MEP-114A). (See Guide to Military Manuals.)
Man-portable Hand Cranked Generators, for field radios, battery charging, and other small power requirements, are covered on the linked Olive-Drab.com page.
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