Here's one for you (almost like a riddle), have you ever considered what would occur if a tram and large haul truck came together in perfect matrimony? A trolley truck.
Tragic humour I know however, these things are no joke and for many countries with alternative energy sources cheaper (and often cleaner) than diesel, may well be the way of the future.
Their rationale makes perfect sense and the results impressive, including less noise, decreased wear and tear, reduced emissions and importantly, increased productivity, derived from increased haul speeds on steep inclines. So, stay with me, as I explore the wonderful world of Trolley Trucks.
In a previous article 'ACDC', you may remember (or more likely not...) that we discussed electric drive dump trucks. A crash course on how this system works – a diesel engine, coupled with an alternator, creates electricity, that is converted by an inverter into AC current, in turn, driving two electric wheel motors at the rear of the truck. Voila, easy!
Just like a Tesla, they're super quick, have greater power than your mechanical dump truck, generate a more consistent and controlled acceleration curve as well as, stronger braking performance, with greater fuel efficiency. All compelling factors, especially if you're a miner. Like the origin of the first electric wheel motor, this technology was derived from trains and has been adopted by Hitachi, Komatsu and more recently Caterpillar.
So how does it work? If you're running existing AC dump trucks, does that mean you'll have to buy an entirely new fleet of trucks? Depends of course upon your fleet however, in many cases your existing trucks can be retrofitted with a contraption known as a 'pantograph', that mounted on the roof, rise off the truck, to touch overhead electric cables. The catch of course being, that you require specific infrastructure including, a power generation facility as well as overhead wiring, just like the trams you may have seen in Melbourne. Why bother?
While it is not something we're likely to see running around the Valley anytime soon, the results are no less than remarkable, with trucks in 'trolley mode' achieving twice the haul speed of conventional units (mechanical and electric) up steep inclines, reducing cycle times, noise as well as wear and tear, with their engines reduced to idle. So much to love!
If you don't believe me and it all sounds a little like gobbledegook, check it out for yourselves on You Tube searching 'Trolley Assist' or 'Electric Drive Truck on Trolley'.
This article was originally published by the Components Only team in the June - July 2018 issue of "@ The Coal Face" magazine.Published 25 June, 2018