Titanic truck moves thanks to multiple massive motors
There are tires that are capable of supporting 110 tons of weight. This is necessary, because eight of them are supporting a vehicle that weighs 397 tons, and the operators would like some allowance to move massive amounts of coal and iron in addition to their amazing truck. The BelAZ 75710 also sports five motors to power it’s dinosaur-sized bulk around, but that’s not just to get more credit with the “bigger is better” crowd. Four of those motors are electric, enabling this huge truck run 25% more efficiently than its smaller predecessors.
At 65.6 feet long, it’s not terribly surprising that this truck can only reach 40 miles-per-hour. It’s clearly not worried about speed as much as carrying the equivalent weight of seven fully loaded Airbus A320-200 airplanes, or around two-and-a-half adult blue whales, for the zoologically inclined. This much weight obviously requires a lot of power, and so it’s driven by four electric motors, capable of cranking out the equivalent of 1,800 horsepower each.
Too big to plug in
Heavy construction companies, like the BelAZ mining company in Siberia that commissioned the truck, have used electric vehicles before. The catch is that they’ve been more like trolleys, requiring access to overhead electric lines to operate. This is where the truck’s fifth engine comes into play, as it’s actually there to simply power generators for the electric motors. Even as a diesel engine, this arrangement ends up being more efficient than using combustion engines to power the truck’s movement directly.
Some of that efficiency is just due to the nature of internal combustion engines. The fans, pistons, air compressors and pumps all need energy to operate, and at low throttle that might be a net loss, which is why most engines drive at a few thousand rpm. By powering a generator, the diesel engine can stay at it’s most efficient operating range, even when the truck wants to slow down. For movement, the electric motors don’t need to spin up parts to get going, offering close to full torque at 0 rpm, which is great when you’re moving a super-heavy machine without a need for tons of speed.
Oddly, even in discussions of moving this much weight around at reasonable speeds, nobody ever mentioned what the brakes looked like.
Source: The World’s Biggest Dump Truck is Electric by Melissa C. Lott, Plugged In