| 摘要 |
A clearance pulse is passed from a triggering unit (17) to a generator blocking unit (11), blocking a master generator (2) for a period sufficient for charging of the electrolytic capacitors of the filter of a power supply unit (6), after which the generator (2) is triggered and produces pulses of min. length. A sensor (12) passes a blocking pulse to the generator (2) during absence of an object. During presence of an object for heating, the generator is not blocked and a frequency tuning unit (13) sets the frequency of the generator according to the heated object and its action on an inductive loop (5). A power control unit (20) sets a determined length of pulses from the generator, to establish the required intensity of heating, while a power limiting unit (14) monitors the voltage from a pulsation level determn. unit (16). If the consumption current of an inverter (1) exceeds a set permitted value, the limiting unit (14) reduces the power through the control unit (20), preventing overloading of a set (4) of current switches. On reaching of the set temp, a load temp, sensor (2) is triggered and the temp. is maintained at the required level. After removal of the object from the working zone, the signal from the sensor (12) passes to the blocking unit, disconnecting the heater. |
