POWER CABLE DISCONTINUITY DETECTING DEVICE FOR ELECTROSTATIC SPRAY GUN WITH BUILT-IN HIGH VOLTAGE GENERATOR

摘要

PURPOSE: To quickly find the discontinuity of a power cable by inserting a resistance between a DC power source and an inverter in series so that when potential difference across the resistance is larger than a set value, an on signal may be outputted, and when a power source voltage detector also outputs an on signal, an abnormal signal may be outputted. ;CONSTITUTION: When a power source is normally operated and a power cable 6 is not disconnected, the electric current flows in a resistance 7 to produce potential difference across it. The potential difference is amplified a differential amplifier 8 and inputted to a comparator, where it is compared with a set value. At this time, since the detected potential difference is larger than the set value, the comparator outputs an off signal. Therefore, an abnormal signal is not outputted. When the power cable 6 is disconnected, however, the electric current does not flow in the resistance 7, and there is no potential difference across it and the detected potential difference is smaller than the set value, allowing the comparator to output an on signal. As a result, an abnormal signal output device is operated to alarm abnormality.;COPYRIGHT: (C)1996,JPO