Abstract: The present invention is designed to detect instantaneous variations in the current flowing through a motor (5), instantaneous variations in the rotation of an agitating body (4), or instantaneous variations in the rotation of the motor (5) to thereby detect the washing load size. On the basis of the detection signal, the washing process is controlled to make it possible to properly set the washing bath ratio, detergent concentration, washing time, and number of revolutions of the fabrics being washed.

Abstract: A plurality of switches each is provided in the vicinity of each of a plurality of heater coils of an induction heating apparatus, and responsive to removel of a cooking implement from a corresponding heater coil for being rendered open. A plurality of timers each is connected to each of the switches and causes the heater coil to be de-energized when the cooking implement is kept away from the heater coil for more than a predetermined time period.

Abstract: A protection device for a thyristor inverter circuit of an induction heating cooking oven wherein commutation failure of a thyristor is detected by determining that the conduction period of the thyristor is outside a predetermined period or that a voltage applied to the thyristor is outside of a predetermined magnitude. The protection device deactuates the inverter to prevent breakdown of the thyristor and reduces the number of operations of the circuit breaker which is a final protection device. Additionally provided are linked switch actuator apparatus for placing a switch for actuating a thyristor control circuit in a state in which it is always actuated in advance of the actuation of a switch for a heating coil in order to prevent occurrance of a transient high voltage due to the switching of an inductive load in the inverter circuit, and an overheating protection circuit for detecting an abnormal temperature rise of the heating coil and an abnormal load condition to deactuate the inverter.

Abstract: An induction heating apparatus includes a saturable reactor having a pair of rectangular ferrite cores. An air gap is provided in each ferrite core to provide a gradually increasing saturation characteristic on the magnetization curve of the cores. A pair of series-connected load windings is coiled around each core and a control winding is coiled around a common magnetic path of the cores. A power control circuit produces a DC control current that passes through the control winding. The high frequency energization current is passed through the load windings. Means are provided to control the DC control current at a desired setting. Preferably, the actual power level is detected to control the DC current through a feedback loop.

Abstract: A hot air drying machine for drying materials, such as clothes or the like, includes a drum for materials to be dried rotatably supported in a housing, a fan casing communicated with the drum and enclosing therein a fan rotated simultaneously with the drum by a driving motor, and heaters for heating air sucked into the housing from exterior thereof. The drying machine further includes an electrical control circuit connected to a first temperature sensing element for hot exhaust air and a second temperature sensing element for the cool outside air sucked into the housing with the operational ratio of the first sensing element to the second sensing element adapted to vary depending on the power source voltage fluctuation for achieving uniform drying rates regardless of the variations of the power source voltage.