Abstract: A resonance type high frequency heating apparatus comprising; a direct current power supply; a series connection circuit consisting of a pair of semiconductor switching elements connected in parallel to the direct current power supply; another series connection circuit having a primary coil of a leakage transformer and a capacitor connected to both ends of one of the pair of semiconductor switching elements; and a drive means for driving each of the pair of semiconductor switching elements; wherein a variable dead time preparation circuit is provided in the drive means, and the variable dead time preparation circuit enables dead time to remain constant at below a predetermined frequency and causes the dead time to increase sharply at a point above a predetermined frequency.

Abstract: An object of the present invention is to provide an inverter circuit in which soft start can be implemented by a simple circuit added thereto. In high-frequency heating apparatus for driving a magnetron, a DC power supply is chopped by two semiconductor switching devices, and this is output as an AC current through a resonance circuit. The high-frequency heating apparatus includes a dead time generation circuit for turning off the semiconductor switching devices concurrently. In the high-frequency heating apparatus, a drive unit for driving the aforementioned semiconductor switching devices has a function of limiting the lowest frequency of a frequency with which the semiconductor switching devices are driven. The aforementioned lowest frequency is set to be high at the beginning of operation of the high-frequency heating apparatus, and the aforementioned lowest frequency is set to be lower gradually thereafter.

Abstract: A purpose of the present invention is to provide an inverter circuit capable of suppressing an overshooting phenomenon of an input current at an instantaneous time when an initiating operation of the inverter circuit is switched to the normal operation thereof, and thus, capable of preventing damages of IGBTs and a magnetron.

Abstract: A drum type washing machine includes a housing; a rotary drum having a substantially horizontal or slanted rotational axis; a water tub, suspended in the housing, for accommodating therein the rotary drum; a controller for controlling an operation of the washing machine; and a displacement detecting unit disposed between the water tub and a base portion of the housing, for detecting displacement of the water tub. The displacement detecting unit has a primary coil wound around a bobbin; a first secondary coil without overlapping the primary coil and a second secondary coil overlapping the primary coil, the first and the second secondary coils being wound coaxially with the primary coil; and a magnetic body vertically movable inside the bobbin corresponding to a displacement of the water tub.

Abstract: A resonance type high frequency heating apparatus comprising; a direct current power supply; a series connection circuit consisting of a pair of semiconductor switching elements connected in parallel to the direct current power supply; another series connection circuit having a primary coil of a leakage transformer and a capacitor connected to both ends of one of the pair of semiconductor switching elements; and a drive means for driving each of the pair of semiconductor switching elements; wherein a variable dead time preparation circuit is provided in the drive means, and the variable dead time preparation circuit enables dead time to remain constant at below a predetermined frequency and causes the dead time to increase sharply at a point above a predetermined frequency.

Abstract: A washing machine includes a rotary drum for accommodating therein laundry, the rotary drum having a horizontal or slanted rotational axis; a water tub supported in a vibratable manner in a washing machine main body, the rotary drum being installed in the water tub in a rotatable manner; a motor for driving the rotary drum; an input setting unit for setting an operation of the washing machine; a control unit for controlling the motor and the operation of the washing machine set by the input setting unit, the control unit including a microcomputer; and a displacement detection unit for detecting a displacement of the water tub. The displacement detection unit includes an excitation coil, at least two detection coils having an axis coaxially aligned with the excitation coil and a core which can move along the axis.

Abstract: A purpose of the present invention is to provide an inverter circuit capable of suppressing an overshooting phenomenon of an input current at an instantaneous time when an initiating operation of the inverter circuit is switched to the normal operation thereof, and thus, capable of preventing damages of IGBTs and a magnetron.

Abstract: A washing machine includes a rotary drum, a water tub, a supporting metallic part, a washing machine base, a motor, a controller, and a vibration detecting unit. The vibration detecting unit, inclusive of a differential transformer having a plurality of coils and a magnetic body, is disposed between the supporting metallic part and the washing machine base and detects a vibration of the water tub.

Abstract: An object of the present invention is to provide an inverter circuit in which soft start can be implemented by a simple circuit added thereto. In high-frequency heating apparatus for driving a magnetron, a DC power supply is chopped by two semiconductor switching devices, and this is output as an AC current through a resonance circuit. The high-frequency heating apparatus includes a dead time generation circuit for turning off the semiconductor switching devices concurrently. In the high-frequency heating apparatus, a drive unit for driving the aforementioned semiconductor switching devices has a function of limiting the lowest frequency of a frequency with which the semiconductor switching devices are driven. The aforementioned lowest frequency is set to be high at the beginning of operation of the high-frequency heating apparatus, and the aforementioned lowest frequency is set to be lower gradually thereafter.

Abstract: There is constructed a constitution such that a shunt resistor 30 is interposed in series with a portion capable of measuring an output current of a unidirectional power source portion 1 of a high frequency heating apparatus and a voltage generated at the shunt resistor 30 is outputted by a buffer 31. Further, an operational amplifier 3101 having a high input impedance is used for the buffer 31. Further, a diode bridge 101 and a semiconductor switching element 205 are fixed to a common heat radiating plate 33, the heat radiating plate 33 is formed with a notched portion 33a to thereby ensure insulating distances to the diode bridge 101 and the semiconductor switching element 205, and the shunt resistor 30 is arranged on a straight line the same as that between the diode bridge 101 and the semiconductor switching element 205.

Abstract: A drum type washing machine includes a housing; a rotary drum having a substantially horizontal or slanted rotational axis; a water tub, suspended in the housing, for accommodating therein the rotary drum; a controller for controlling an operation of the washing machine; and a displacement detecting unit disposed between the water tub and a base portion of the housing, for detecting displacement of the water tub. The displacement detecting unit has a primary coil wound around a bobbin; a first secondary coil without overlapping the primary coil and a second secondary coil overlapping the primary coil, the first and the second secondary coils being wound coaxially with the primary coil; and a magnetic body vertically movable inside the bobbin corresponding to a displacement of the water tub.

Abstract: A washing machine includes a rotary drum, a water tub, a supporting metallic part, a washing machine base, a motor, a controller, and a vibration detecting unit. The vibration detecting unit, inclusive of a differential transformer having a plurality of coils and a magnetic body, is disposed between the supporting metallic part and the washing machine base and detects a vibration of the water tub.

Abstract: A washing machine includes a rotary drum for accommodating therein laundry, the rotary drum having a horizontal or slanted rotational axis; a water tub supported in a vibratable manner in a washing machine main body, the rotary drum being installed in the water tub in a rotatable manner; a motor for driving the rotary drum; an input setting unit for setting an operation of the washing machine; a control unit for controlling the motor and the operation of the washing machine set by the input setting unit, the control unit including a microcomputer; and a displacement detection unit for detecting a displacement of the water tub. The displacement detection unit includes an excitation coil, at least two detection coils having an axis coaxially aligned with the excitation coil and a core which can move along the axis.

Abstract: Since the exposed collector part 32 of one semiconductor switching element 29 is attached to the heat radiating fin 42 by coating and filling a thermal conducting filler therebetween via spacers 33, 34 and 35, and the exposed collector part 37 of another semiconductor switching element 36 is directly attached to the same heat radiating fin 42 by coating the thermal conducting filler 41 thereto without any spacer, heat resulting from switching losses can be effectively transmitted to the heat radiating fin 42 and can be radiated therefrom. To effectively transmit heat, which results from switching losses, to a heat radiating fin and to radiate the same even if two semiconductor switching elements are connected in series, a collector part is exposed on the rear side thereof, and the two semiconductor switching elements are attached to a single heat radiating fin.

Abstract: Since the exposed collector part 32 of one semiconductor switching element 29 is attached to the heat radiating fin 42 by coating and filling a thermal conducting filler therebetween via spacers 33, 34 and 35, and the exposed collector part 37 of another semiconductor switching element 36 is directly attached to the same heat radiating fin 42 by coating the thermal conducting filler 41 thereto without any spacer, heat resulting from switching losses can be effectively transmitted to the heat radiating fin 42 and can be radiated therefrom. To effectively transmit heat, which results from switching losses, to a heat radiating fin and to radiate the same even if two semiconductor switching elements are connected in series, a collector part is exposed on the rear side thereof, and the two semiconductor switching elements are attached to a single heat radiating fin.

Abstract: A primary winding (1) and a secondary winding (2) are layered concentrically with a magnetic substance forming a main magnetic circuit (13) and the magnetic resistance of a subordinate magnetic circuit (14) placed between the primary winding (1) and the secondary winding (2) is adjusted, whereby a concentric multilayer winding transformer having an arbitrary coupling coefficient can be provided.

Abstract: In a microwave heating oven, a safety switch 301 is disposed in an external position relative to a heating chamber 100. A displacement rod 302, which is made of polyprophylene or the like low dielectric constant plastic substance, is disposed through and across the heating chamber 100. Displacement rod 302 serves as a thermal switch, so that at an abnormally high temperature displacement rod 302 melts down, thereby opening the safety switch 301 and disengaging the microwave generator.