Abstract: A compressor includes a motor driven by a controller and having a rotor and a stator, a compressing unit driven by the motor in a hermetic container in which refrigerant is filled. Driving the motor at a low rpm, the controller practices a feedback control which determines a timing of turning on/off switching elements based on a signal detecting a position of the rotor, and when the motor is driven at a high rpm, the controller practices an open-loop control which outputs a given frequency and drives the motor synchronizing with the given frequency. This structure achieves a compressor working with a fewer noises in PWM driving.

Abstract: The present invention solves a problem that a power controller be large in a refrigerating system, and provides a compact-size as well as an inexpensive power controller. Highly heat-dissipating first board 1 including an inverter circuit mounted thereon and second board including a control circuit mounted thereon are placed in parallel with each other and accommodated by case 9. Case 9 has slits through which heat sink 2 and connector 6 can extend outside case 9, and further has fixing section 11 for fixing case 9 to a compressor. This structure allows the power controller to dissipate heat in an optimum manner and to be downsized, and also allows the compressor to integrate the controller thereinto. A capacity that the controller occupies in the refrigerating system can be substantially reduced.

Abstract: The present invention relates to an electric power unit with a condenser input type rectification circuit which converts an alternating current power source to a direct current voltage, and more particularly, to an electric power unit for inverter-controlled refrigerators. An electric power unit according to the present invention feeds electric power to a load (7), which comprises an alternating current power source (1), a bridge-type rectification circuit (2) having an input from the alternating current power source (1) and consisting of bridge-connected diodes (D1, D2, D3, D4), an auxiliary capacitor (3) connected in parallel to an output of the bridge-type rectification circuit (2), a series circuit of a reactor (4) and a diode (5) connected between one output of the bridge-type rectification circuit (2) and the load (7) so as to flow a load current in a forward direction, and a smoothing capacitor (6) connected in parallel to the load (7).

Abstract: A linear motor comprising prismatic inner yokes each constructed in a manner that a large number of sheets each having a generally rectangular configuration and having a high magnetic permeability are piled up each other and outer yokes each constructed in a manner that a number of sheets each having a generally rectangular configuration and having a high magnetic permeability are piled up each other. Each of coils is wound around a central portion of three magnetic pole portions of the outer yoke to alternately establish different magnetic poles along a direction of an axis of the linear motor. A surface of the outer yoke, holding the magnetic pole portions, is disposed in an opposed relation to the inner yoke to define a predetermined gap therebetween so that the inner yoke and the outer yoke form each of a plurality of yoke blocks. The yoke blocks are placed around the axis so that the sheet piling-up direction is perpendicular to a diametrical direction of a shaft.

Abstract: The present invention relates to an electric power unit with a condenser input type rectification circuit which converts an alternating current power source to a direct current voltage, and more particularly, to an electric power unit for inverter-controlled refrigerators.An electric power unit according to the present invention feeds electric power to a load (7), which comprises an alternating current power source (1), a bridge-type rectification circuit (2) having an input from the alternating current power source (1) and consisting of bridge-connected diodes (D1, D2, D3, D4), an auxiliary capacitor (3) connected in parallel to an output of the bridge-type rectification circuit (2), a series circuit of a reactor (4) and a diode (5) connected between one output of the bridge-type rectification circuit (2) and the load (7) so as to flow a load current in a forward direction, and a smoothing capacitor (6) connected in parallel to the load (7).