US Patent 7669393 Stall detection system for mower blade clutch engagement

A stall detection system for mower blade clutch engagement determines if there is a stall condition by sensing one or more operating conditions such as engine deceleration or blade spindle rotation. If a stall condition is detected, a microcontroller shuts off actuating current to the electric clutch coil and automatically disengages or discontinues engagement of the clutch. The microcontroller may also provide a signal to inform the operator of the stall condition, and prevent repeated activation of the clutch until the stall condition is corrected.