| 主权项 |
1. A resistance measuring apparatus, comprising:
a voltage injector that injects a testing AC signal into a measured circuit by applying an AC voltage to an injection coil; a current measurer that detects and measures an AC current, which is flowing in the measured circuit due to injection of the testing AC signal, using a detection coil; a processor that calculates a resistance value of the measured circuit based on a voltage value of the injected testing AC signal and a measured value of the AC current; and a single clamp-type housing that houses the injection coil and the detection coil, wherein: the voltage injector applies a signal that is synchronized to a reference signal as the AC voltage, the current measurer converts a current flowing in the detection coil due to the injection of the testing AC signal to a voltage signal, carries out synchronous detection on the voltage signal using the reference signal, and measures a current value of the AC current based on a signal obtained by the synchronous detection, the single clamp-type housing includes a first housing and a second housing that respectively house the injection coil and the detection coil, the first housing and the second housing each has a three-piece structure divided in three separate parts in a thickness direction thereof, the three parts including a middle housing and a pair of side housings that are disposed in the thickness direction, the middle housing includes a first plate-shaped member formed with the same planar shape as a planar shape of a corresponding one of the first housing and the second housing, a first wall portion that is positioned on one surface of the first plate-shaped member along an outer edge of the first plate-shaped member, and a second wall portion positioned on the other surface of the first plate-shaped member in the opposite direction to the first wall portion along the outer edge of the first plate-shaped member, one side housing of the pair of side housings includes a second plate-shaped member formed in the same planar shape as a planar shape of a corresponding one of the first housing and the second housing, and a third wall portion that is positioned on a surface of the second plate-shaped member that faces the middle housing along an outer edge of the second plate-shaped member, the other side housing of the pair of side housings includes a third plate-shaped member formed in the same planar shape as a planar shape of a corresponding one of the first housing and the second housing, and a fourth wall portion that is positioned on a surface of the third plate-shaped member that faces the middle housing along an outer edge of the third plate-shaped member, the first housing and the second housing are constructed so that in a state where the third wall portion and the first wall portion have been joined and the fourth wall portion and the second wall portion have been joined, the pair of side housings are disposed on both sides of the middle housing so as to sandwich the middle housing and gaps are respectively formed between the middle housing and the pair of side housings, the injection coil and the detection coil are disposed in the respective gaps of the housing, stacked in a thickness direction of the injection coil and the detection coil, and the housing is composed of an insulating resin material. |
