Force to reckon with

Direct drive motors, both mechanical and electrical, are used where a steady load or fixed speed is required. But for applications such as the car — which relies on a power transmission system based on gears, linkages and a clutch — a more complex solution is needed.

Without some kind of gearing system the rotational speeds required to move a car at any speed beyond the average for London traffic would be so high as to be inefficient and would probably shake an average SUV apart in a matter of months.

Even if an internal combustion engine could be manufactured to produce a suitable output — a typical engine runs at between 600 rpm and 7,000 rpm — the car's wheels typically revolve at around 0-1800 rpm.

The same problems apply to industrial applications where large forces need to be transmitted.

South Africa-based

, for example, has received an order from F L Smidth Minerals to supply a gear weighing some 65 tonnes as part of a contract for Armenia. The gear is so big it will have to be transported in four sections to the republic.