Alternate Currents

From DC/AC Power Converters to "More Electric"

By Richard LeFrancols, President, Equipment Maintenance Innovators

August 2004

 

In 1987, which was early in my career of selling truck equipment, I was introduced to the DC/AC Power
Inverter. These devices, when mounted on a vehicle, allow users to power up an AC hand tool, a roof
mounted air conditioner, a coffee maker or a microwave.

Many a lineman ln the utility or cable TV industry will attest to this fact: having clean electrical power
Independent of the truck's engine and electrical system is crucial to those involved in the fiber optic cable
splicing business.

During this time I was fortunate to have the pleasure of working with a gentleman by the name of Paul
Mitchell, President of Mobile Power, Hackettstown, N.J. To this day in the DC/AC Power Inverter industry,
most people that know Paul would consider him the foremost authority on making a DC/AC Power Inverter
work on the multitude of engine/electrical system combinations available in the marketplace.

Paul is the only guy I know of that could look at an engine compartment and the pulley assembly to figure
out how to mount not one, but sometimes two, additional alternators off a truck engine.

He would also design the mounting brackets, figure out the proper belt size, and determine how many extra
batteries he had to add to the system to make it all work.

The downside is that you have a high maintenance system and add weight to the truck. That's something all
of us would like to get away from!

But, companies such as Tele-Communications (now Comcast), Verizon and a multitude of other cable TV,
Telephone and utility companies utilize PauI‘s services to "make those things work."

Now, let us fast fonvard to today where the demand for power off the truck engine has increased with the
addition of electronics associated with vehicle tracking systems, driver management systems, and the ever
present pumps, compressors, alternators and other engine accessories. Spare is not only a huge problem but
all these accessories working together via the pulleys and bolts steal from a truck engine's horsepower and
fuel economy.

One effort to address the above issue is a program launched by the U.S. Department of Energy, titled "More
Electric Truck." The program, administered by the Argonne National Laboratory, consists of industry partners
Caterpillar, Inc., Kenworth Truck Company, Emerson, and Engineered Machined Products ( EMP).

According to a U.S. Department of Energy FreedomCar and Vehicle Technologies Program document, the
project is a Collaborative $4.8 million government-industry cost-shared team effort.

Caterpillar provided engine technology, mechanical design, electronics, controls and overall systems
integration, Kenworth supplied truck expertise, test vehicle and testing capabilities; Emerson offered its
electric motor and power electronics knowledge; and FMP developed the new electically driven water and oil
pumps," according to the U.S. Department of Energy.

The project introduces new technology that would take the load off the engine, utilizing eIectricaIly-powered
accessories in lieu of mechanically-powered ones, to reduce weight and minimize costs.

Such a system would allow accessories to operate independently of the engine and allow them to perform at
their required rate, be it flow, pressure or speed.

The heart of the system is a new concept. The More Electric Truck powers electricaIIy-driven accessories
through a generator located inside the flywheel housing. This generator is also utilized as the starter motor
for the engine. Systems converted by the technology to electrical power are HVAC, brake air compressor and
the oil and water pumps.

The package offers "electrically driven heating, ventilating, and air-conditioning (HVAC) plus a high-efficiency
30Kw generator," according to the U.S. Department of Energy. In addition, the unit includes an integrated
auxiliary power unit ( APU) and a "shore power" capability to take advantage of the current initiatives to offer
electricity at parking spaces for trucks at truck stops. This permits the truck to have the same electrical
capability as a recreational vehicle at a campground.

According to David Orr, commercial manager, Caterpillar Electronics Business Unit, "The technology uses
critical enablers from the hybrid vehicle industry. Hybrid vehicles need 270-400v to launch a car at start. Our
system utilizes a 340v power leverage to drive the electrical system."

According to the U.S. Department of Energy, "These and future electrically driven devices, once commercially
developed and validated, will start to appear on vehicles throughout the trucking industry."