Patent ID: 7664615

Claim:
A method for determining a critical reduction in shaft speed in a work machine having at least one monitored shaft driven by a crankshaft of an engine, comprising: (a) determining an actual rotational speed of said crankshaft; (b) determining an actual rotational speed of a first monitored shaft; (c) determining a filtered rotational speed of said first monitored shaft based on an algorithm that utilizes said actual rotational speed of said first monitored shaft, said actual rotational speed of said crankshaft, and a reference rotational speed of said crankshaft; (d) comparing said filtered rotational speed of said first monitored shaft to said actual rotational speed of said first monitored shaft; (e) determining whether said actual rotational speed of said first monitored shaft deviates from said filtered rotational speed of said first monitored shaft by a predetermined amount; and (f) activating an alarm if said actual rotational speed of said first monitored shaft deviates from said filtered rotational speed of said first monitored shaft by said predetermined amount; and wherein acts (a) through (e) are performed for a predetermined time, and if said actual rotational speed of said first monitored shaft deviates from said filtered rotational speed of said first monitored shaft by said predetermined amount at the end of said predetermined time, then activating said alarm.