An engine driven fan unit was put together using a used 50hp Typhoon centrifugal fan unit and a used 6cylinder Perkins diesel engine from a combine.
A chassis was designed and built for the engine with screw adjustment to tension the belt drive to the fan.
The bottom pulley was especially made to take a slip clutch that allows the fan to continue running when the engine stops. With this arrangement the engine needs to have a significantly larger power output than the fan requires so that the engine, on starting, can turn the fan over. A sprung loaded jockey pulley is also included in the drive arrangement to take up any snatch in the belts on starting.
An alternative arrangement which provides for a gradual take up of the drive to the fan would be to use a centrifugal clutch. Although this is a more expensive option it does allow for a smaller engine or is suitable for larger fan units.
The engine is supplied with a control panel that provides for engine protection if overheating or lack of oil pressure occurs.