| 摘要 |
<p>PURPOSE:To securely detect a phase of an unconnected line by performing operation for actuating a main circuit, closing two phases with a servo motor and confirming a current flow on the circuit with respect to all combinations of the two phases. CONSTITUTION:First, a low voltage at a main circuit DC voltage is charged by a thyrister 1 in order to prevent a large torque from appearing on a servo motor 7. Then power transistors 3U1, 3V2 and 3V1, 3U2 are ignited so that current flows from a U-phase to a V-phase and from the V-phase no the U-phase to check an actual flow of the current by a current detector 6. Similarly the current is made to flow from the V-phase to a W-phase, from the W-phase to the V-phase, from the U-phase to the W-phase and from the W-phase to the U-phase to detect 6 the actual flow of the current. Then a CPU 4 inputs and determines the results on the current flow to the respective phases, and if current flows in all cases, processing is completed as all of the phases have been connected. If current does not flow on any phase, the current flow on combinations of the respective phases is determined from data to have unconnected wires detected.</p> |
