Forage Harvester

A processing system for a forage harvester, comprising:

• an input for receiving power from a prime mover;
• a cutting system for cutting crop material;
• a drive system for driving the cutting system;
• an accelerator for generating a flow of the cut crop material;
• a controllable flap along the flow path between the cutting system and the accelerator, having an open position to allow relatively large objects to pass through and a closed position;
• and
• a hydraulic circuit, wherein the hydraulic circuit comprises:
• a primary hydraulic pump and a coupled hydraulic charge pump, actuated by the power received at the input;
• and
• a hydraulic actuator for controlling the position of the controllable flap,
• wherein the controllable flap is configured to move to its open position when the input power received at the input is interrupted and wherein the hydraulic actuator is supplied with a supply pressure from the hydraulic charge pump.