Abstract
A means of preventing a work machine (100 fig.1) from contacting an overhead power line (109 fig.1) has a electric field sensors (120 fig.1) and position or movement sensors (122 fig.1) that may be associated with an implement such as a bucket (114 fig.1). The sensor outputs are continuously monitored and at 420 if a combination of the sensor data, such as a dot product of the electric field with the implement or machine velocity, exceeds a predetermined threshold an alert is issued 430. If a second, higher, predetermined threshold is reached 450 a further alert may be issued 460 and control of the machine may be started which may include derating the performance of the machine by reducing the velocity of the machine or implement or stopping it entirely. The operator may override the controls to regain movement of the machine or the system may control a safe exit from the hazardous area, possibly by reversing the machine movement, the history of which may have previously been stored.