公开(公告)号：US3657602A

公开(公告)日：1972-04-18

申请号：US3657602D

申请日：1971-04-05

Applicant: INDUCTOTHERM CORP

Inventor： BOEHM PAUL C ,  KENNEDY THEODORE R

IPC: H02H7/16

CPC classification number: H02H7/16

Abstract: Incipient failure of a capacitor operating as a part of an induction furnace circuit is detected by monitoring the capacitor to determine the presence of high-frequency signals generated by the capacitor as its dielectric material deteriorates. The lower limit of the frequencies of such signals is in the range from 50 to 200 kHz. The sensing apparatus for a 3 kHz induction heating circuit includes detector means for converting the generated signals exceeding about 150 kHz into a control signal whose level exceeds a predetermined value when the generated signals are representative of incipient deterioration of the dielectric. Indicator means responsive to the control signal is operated when the latter signal exceeds said predetermined value, and may disconnect power from the capacitor.

Abstract translation: 通过监测电容器来检测作为感应电炉电路的一部分操作的电容器的初始故障，以确定当电介质材料劣化时由电容器产生的高频信号的存在。 这种信号的频率的下限在50至200kHz的范围内。 用于3kHz感应加热电路的感测装置包括检测器装置，用于当所产生的信号代表电介质的初始劣化时，将产生的超过约150kHz的信号转换成电平超过预定值的控制信号。 响应于控制信号的指示装置在后一信号超过所述预定值时被操作，并且可以断开电容器的电源。