| 摘要 |
PURPOSE:To detect a load abnormality, by obtaining specific relations between the plate input current and the grid current of an oscillating circuit at the operation start time and after the secular change in an electron tube type oscillating device used in an industrial heating equipment or the like. CONSTITUTION:For example, an output obtained by rectifying an AC power source AC by a rectifier RE is supplied to an oscillating circuit OSC in an industrial heating equipment, and a work coil WC is loaded. The circuit OSC uses an oscillating tube B to self-oscillates. A load abnormality detecting part 1 is controlled by a control part 11, and an operation command Re is inputted to the detecting part 1, and an abnormality output (o) is outputted. The command Re reads a plate input current Ip0 and a grid current Ig0 at the operation start time of the oscillating tube V and instructs the operation. The operation result is stored in a storage part 15, and a signal L of an abnormality detection level determined by expression is inputted to an operating part 14. At the operation time, a plate input current Ip and a grid current Ig are read out and are operated to detect load abnormality. |
