In most offerings, all items except the piping and hydraulic motor are housed in a sound insulated cabinet. The swash plate pump is driven by an electric motor running efficiently at fixed speed.

The oil flow from the pump is determined by the swash-plate angle, which is controlled by a signal from the control system. Starting in an unloaded, neutral condition, the system ramps the flow up to the required direction and rate and pressure is determined by the load up to the limit set at the compensator. If pressure reaches compensator setting the pump will destroke, stopping the drive, so eliminating heat buildup but maintaining the set pressure and therefore torque at the drive. The pump will stay in this condition until the system is unloaded where upon the pump will immediately ramp up to the set Flow rate or until the control is adjusted. The pump and the hydraulic motor are connected together by flexible hoses and piping if necessary.

At the motor the oil is distributed through the valve plate to the pistons in the cylinder block 50% of them with high pressure and 50% with charge pressure. The oil pressure forces the piston assemblies radially outwards against the cam-ring. This produces a balanced and smooth rotation with extremely high torque which drives the machine. The speed of the motor is controlled by the flow of oil from the pump. Drive motor speed is therefore proportional to the swash plate angle of the pump.If the swash plate is controlled over-centre, the flow is reversed and the motor direction is therefore reversed.

Both the hydraulic motor and the pump have a very low moment of inertia, which makes it possible to change speed and stop or reverse direction quickly.

A proportion of the return flow is used to provide oil conditioning by cooling and filtering. The oil in the motor and pump case which provides lubrication and local cooling is fed back to tank via an adequately sized drain line.