The Caterpillar 3508 mechanical generator and engine package powers many of the locomotives that are used for freight and passenger trains throughout the world. It has also been adapted for use as a backup electrical power generator in data centers and hospitals. The engine, which runs on diesel fuel, powers a flywheel generator that produces the electricity which is needed to operate the equipment.
The Caterpillar 3508 measures 194 inches (16 feet 2 inches) long by 67 inches (5 feet 7 inches) wide by 78 inches (6 feet 6 inches) high. It weighs 24,290 lbs. (12 tons, 290 lbs.) and its cast metal casing is painted in the trademark Caterpillar orange-yellow color.
Engine Size and Capacity
The Caterpillar 3508 has a 8 cylinder, 4-stroke diesel engine. The engine bore measures 6.7 inches and it produces a 7.5 inch long piston-cylinder travel stroke. Its displacement size is 2,105 cubic inches (34.5 liters) and its aspiration method is turbocharged-aftercooled. The cooling system of the Caterpillar 3508 has a capacity of 30 gallons and the engine requires 112 gallons of motor oil for lubrication. Its fuel usage is one gallon per hour at idle speed and 50.6 gallons at peak speed.
The flywheel meets SAE (Society of Automotive Engineers) No. 00 specifications as does its housing; the flywheel has 183 teeth. It rotates in a counterclockwise direction according to SAE standard rotation and its maximum speed is 1,800 revolutions per minute (rpm). It is rated at 1,000 brake horsepower or 746 brake kilowatts. At low idle, the speed of the flywheel of the Caterpillar 3508 reduces to 600 rpm and its operating range is 1,200 rpm between idle and peak. It can operate at full capacity when used at altitudes up to 5,000 feet, and at altitudes higher than that it loses power at the rate of 30 brake horsepower per 1,000 feet of additional altitude.
Alternator (Electrical) Power and Characteristics
The Caterpillar 3850 is equipped with a KATO 8P6.5-1900 alternator that produces 700 volts DC at 6,000 ADC intermittent power or 4,000 ADC continuous power. This main alternator has two bearings and it is close coupled to the engine and viscous coupled to the flywheel. It is common base mounted and includes a single-stage internal cooling fan as well as 3-phase AC power rectification components.
The 3850 is equipped with a KATO 6P2.5-1450/6P2-0500 dual auxiliary alternator for 3-phase 220 volt AC, 150 kilovolt-ampere power. The auxiliary alternator also has a boost circuit for equipment such as cooling fans and compressors. It also includes internal rectification to convert the AC output to 74 volts DC at a minimum of 18 kilowatts for battery charging.