Patent ID: 7816903
Filing Date: 2010-10-19
Classification: G01R

Abstract:
1. A single-phase 3-wire power line connection determination apparatus comprising: a voltage detection circuit that detects a voltage between a ground probe terminal, which is brought into contact with a ground potential body and is at near-ground potential, and a hot probe terminal, which is brought into contact with either of a pair of terminals of a power outlet that is connected to a single-phase 3-wire power line, and that identifies the terminal at which a high potential difference has been detected as the hot terminal that is connected to either a first outer wire or a second outer wire of said single-phase 3-wire power line; a zero cross detection circuit that compares the potential of the AC voltage of the hot probe terminal contacting said hot terminal of the power outlet with a standard potential of the ground probe terminal at near-ground potential, and that detects a zero cross time at one of a rising zero cross point at which the AC voltage crosses the standard potential when rising and a falling zero cross point at which the AC voltage crosses the standard potential when falling; timing means that measures the elapsed time from a first zero cross time, which is detected when said hot probe terminal is brought into contact with said hot terminal of a first power outlet, to a second zero cross time, which is detected when said hot probe terminal is brought into contact with said hot terminal of a second power outlet; and a connection determination means that, if the elapsed time from said first zero cross time to said second zero cross time is an integral multiple of the cycle of said AC voltage, determines that said hot terminals of said first power outlet and said second power outlet are connected to a common first outer wire or second outer wire.