The blowers are usually driven from the engine cranks shaft by mean of Spur, helical or herringbone
gears, silent chains or V-belts at a speed 2-3 times the engine speed. In the case of turbo-supercharger,
the super charger is coupled to a gas turbine in which the exhaust of the engine is expanded.
The positive displacement types are used for low and medium speed engines with speeds not
over 4000 rev/min. Positive displacement type used with many reciprocating engines in stationary plants,
vehicles and marine installations.