The ZEXEL RHD 10 governor is a hydraulic engine governor used primarily on diesel engines — especially large industrial or marine diesel engines (such as ship main engines and generator sets). Its main job is to control and regulate engine speed by adjusting fuel delivery based on load and speed demand It’s manufactured by ZEXEL Corporation (Japan), known for diesel fuel injection and engine control system components. ✔ Monitors engine speed and load changes ✔ Adjusts the fuel supply to maintain a stable RPM ✔ Helps prevent overspeeding or surging ✔ Can operate in isochronous mode (no speed droop) or with adjustable droop for load sharing in multiple-engine setups