Patent ID: 7171879

Claim:
For use on power equipment having at least one dangerous portion, a method of detecting dangerous proximity between a person and the dangerous portion, the method comprising: generating a high voltage; applying the high voltage to the dangerous portion, where the high voltage is sufficient to cause an electrical discharge arc between the dangerous portion and the person's body when a portion of the person's body comes within a predetermined distance from the dangerous portion, and where the high voltage on the dangerous portion has an expected amplitude; providing an electronic circuit adapted to detect when an electrical discharge arc between the dangerous portion and the person's body occurs by monitoring the voltage amplitude on the dangerous portion; detecting through the electronic circuit when an electrical discharge arc between the dangerous portion and the person's body occurs by monitoring the voltage amplitude on the dangerous portion and comparing that voltage amplitude with the expected amplitude; and triggering an action to mitigate potential injury when the monitored voltage amplitude departs from the expected amplitude greater than a predetermined threshold amount.