The primary driver is the component that will drive the hydraulic pump and in turn, develop a flow of hydraulic oil. Choice of primary driver will be dictated by the application in which the Hydraulic Power Pack is to be used. For mobile applications typically we utilise the combustion engine output due to a lack of available electrical power. Industrial power pack applications generally utilise electrical motors as their primary drivers. Electric motors provide instant torque, smooth running and quiet operation.
All primary drivers have to be sized specifically for the particular power pack application; it will be their job to provide sufficient horsepower to drive a hydraulic pump capable of delivering the required flow and pressure for the hydraulic circuit.
To calculate the size of the primary mover (typically an electric motor or engine), we must first establish the size of the hydraulic pump to give the required flow for the system. Once we have sized the pump, we then know the power required to drive the pump and specify the correct size motor or engine.