Abstract: There are provided a motor for an injection molding machine, and a rotor of a buried magnet motor. In a plate 22 constituting the rotor 20 of a servo motor, a columnar portion 25 formed between adjacent holding holes 24, 24 serves, at a portion between the inner circumferential end 25a and the intermediate portion 25c, as a holding portion 30 coming into line contact with a permanent magnet 23, which is thereby locked even during acceleration/deceleration of the servo motor. Consequently, the permanent magnet 23 does not butt against a specific part of the columnar portion 25. The gap between the holding portion 30 of the columnar portion 25 and the permanent magnet 23 may be filled with a filler to close the gap between them. Consequently, the permanent magnet 23 does not move in the holding hole 24 even during acceleration/deceleration of the servo motor.

Abstract: A motor driving system for driving an induction motor with a rotation frequency detector. The induction motor drives a load, and the rotation frequency detector detects a rotation frequency of the induction motor. The motor driving system includes a variable speed driving unit and an inverter control unit. The variable speed driving unit is connected to the induction motor and has a capacitance at output. The variable speed driving unit rectifies first 3-phase AC power to produce DC power, and converts the DC power into second 3-phase AC power with a frequency, and drives the induction motor with the second 3-phase AC power. The inverter control unit generates a frequency instruction and a temporary current instruction based on the detected rotation frequency and a rotation frequency instruction at least.

Abstract: The inverter device includes an inverse conversion circuit which converts a supplied direct-current electricity into a alternating-current electricity having a predetermined frequency, and is designed to drive a motor for a rotary machine, at various speeds, in which the switching control of the inverse conversion circuit is performed by a digital processor. In this inverter device, a timer interrupt process having an independent constant processing cycle which is not directly related to the processing cycle of the system control in the digital processor is assigned. In the timer interrupt process, whether or not switching of the inverse conversion circuit is required is determined, and the switching control is carried out on the basis of the determination.

Abstract: A motor driving system drives an induction motor with a rotation frequency detector. The induction motor drives a load, and the rotation frequency detector detects a rotation frequency of the induction motor. The motor driving system includes a variable speed driving unit, and an inverter control unit. The variable speed driving unit is connected to the induction motor and has a capacitance at output. The variable speed driving unit rectifies first 3-phase AC power to produce DC power, and converts the DC power into second 3-phase AC power with a frequency, and drives the induction motor with the second 3-phase AC power. The inverter control unit generates a frequency instruction and a temporary current instruction based on the detected rotation frequency and a rotation frequency instruction at least.

Abstract: The inverter device includes an inverse conversion circuit which converts a supplied direct-current electricity into a alternating-current electricity having a predetermined frequency, and is designed to drive a motor for a rotary machine, at various speeds, in which the switching control of the inverse conversion circuit is performed by a digital processor. In this inverter device, a timer interrupt process having an independent constant processing cycle which is not directly related to the processing cycle of the system control in the digital processor is assigned. In the timer interrupt process, whether or not switching of the inverse conversion circuit is required is determined, and the switching control is carried out on the basis of the determination.