Patent ID: 9746510
Date: 2017-08-29
CPC Classifications: F27B,F27D,G01R,H05B,Y02P

Claim:
1. An installation comprising: two induction furnaces, two respective resonant load circuits each including a respective induction-furnace coil in a respective one of the furnaces, two respective parallel or series connected inverters that are connected to and each supply a respective one of the resonant load circuits, a respective electrical supply line connecting each of the parallel or series connected inverters to a common rectifier connected to an AC current source, a respective ground-fault sensor associated with each induction furnace and connected to the respective electrical supply line and to the respective induction-furnace coil, a ground-leak sensor connected to the inverters, and an additional ground-fault sensor measuring at the same location as the ground-leak sensor and injecting an AC current of low frequency into the furnace circuit and measuring the magnitude of this low-frequency circuit.