Abstract: A multi-motor system includes motor assemblies, each including a motor, a communication circuit to receive a command transmitted from outside, a control circuit to generate a control signal that rotates the motor with a controlled variable that is designated by the command; and a motor driving circuit that causes a current to flow in the motor based on the control signal. The command includes control data indicating the controlled variable of the motor in fixed data length, the controlled variable being expressed at least with an integer, and position-designating data designating a position of the radix point in the control data. The position-designating data is independently determined for each motor assembly.

Abstract: A motor assembly includes a motor, a control circuit to generate a control signal, a motor driving circuit to cause a current to flow in the motor based on the control signal, a storage to store a first identifier uniquely identifying itself and a second identifier uniquely identifying another motor assembly within the communications network, and a communication circuit. The communication circuit transmits a data frame, in which the first identifier indicates a transmitting end, the second identifier indicates a receiving end, and a request are stored. The communication circuit receives from the other motor assembly a data frame including the second identifier indicating a transmitting end, the first identifier indicating a receiving end, and a request. In response the communication circuit transmits a data frame including the second identifier indicating a receiving end added thereto and the first identifier indicating a transmitting end added thereto.

Abstract: A multi-motor system includes motor assemblies, each including a motor, a communication circuit to receive a command transmitted from outside, a control circuit to generate a control signal that rotates the motor with a controlled variable that is designated by the command; and a motor driving circuit that causes a current to flow in the motor based on the control signal. The command includes control data indicating the controlled variable of the motor in fixed data length, the controlled variable being expressed at least with an integer, and position-designating data designating a position of the radix point in the control data. The position-designating data is independently determined for each motor assembly.

Abstract: A motor assembly includes a motor, a control circuit to generate a control signal, a motor driving circuit to cause a current to flow in the motor based on the control signal, a storage to store a first identifier uniquely identifying itself and a second identifier uniquely identifying another motor assembly within the communications network, and a communication circuit. The communication circuit transmits a data frame, in which the first identifier indicates a transmitting end, the second identifier indicates a receiving end, and a request are stored. The communication circuit receives from the other motor assembly a data frame including the second identifier indicating a transmitting end, the first identifier indicating a receiving end, and a request. In response the communication circuit transmits a data frame including the second identifier indicating a receiving end added thereto and the first identifier indicating a transmitting end added thereto.

Abstract: A motor drive system includes motor units to operate in accordance with a unified operation command transmitted from an outside to cause an operation to be accomplished by the motor drive system as a whole. Each motor unit includes a communication circuit to receive the unified operation command, a motor, a storage device to store data representing a rotation direction of the motor associated with the unified operation command, a control circuit, and a drive circuit to cause an electric current to pass through the motor based on a control signal. The control circuit is configured to refer to the data, and generate a control signal to cause the motor to rotate in the rotation direction associated with the unified operation command.

Abstract: According to one embodiment, there is provided a magnetic disk apparatus including an actuator, a shock detection circuit, a temperature measurement circuit, and a controller circuit. The actuator holds a magnetic head that accesses a magnetic disk. The shock detection circuit includes an acceleration sensor that detects acceleration during driving of the actuator. The temperature measurement circuit measures a temperature during driving of the actuator. The controller circuit changes sensitivity of the shock detection circuit according to a temperature change rate obtained from the measured temperature.

Abstract: According to one embodiment, a magnetic disk drive includes a disk, a first microactuator, a second microactuator and a servo controller. The disk comprises a first surface and a second surface. The first and second microactuators allow first and second heads associated with the first and second surfaces to make micromotion based on first and second operation amounts, respectively. The servo controller provides a third operation amount to the first microactuator as the first operation amount and provides an operation amount obtained by inverting a polarity of a frequency component with a particular frequency contained in the third operation amount, to the second microactuator as the second operation amount, if the third operation amount is generated as an operation amount to be provided to the first microactuator in a particular mode in which the first surface is used as a tracking surface.

Abstract: According to one embodiment, a magnetic disk drive includes a disk, a first microactuator, a second microactuator and a servo controller. The disk comprises a first surface and a second surface. The first and second microactuators allow first and second heads associated with the first and second surfaces to make micromotion based on first and second operation amounts, respectively. The servo controller provides a third operation amount to the first microactuator as the first operation amount and provides an operation amount obtained by inverting a polarity of a frequency component with a particular frequency contained in the third operation amount, to the second microactuator as the second operation amount, if the third operation amount is generated as an operation amount to be provided to the first microactuator in a particular mode in which the first surface is used as a tracking surface.

Abstract: In a storage device, before activating a spindle motor (SPM) or continuously from activation until the SPM is stabilized at a target number of rotations, a voltage and temperature monitoring unit monitors the temperature in a disk enclosure unit and the voltage to be applied to an SPM driver. A current limit value calculating unit calculates an optimum current limit value not exceeding a rated current of the SPM driver, and a motor controlling unit controls the SPM driver and changes the current to be applied to the SPM so that the current does not exceed this optimum current limit value.

Abstract: In a storage device, before activating a spindle motor (SPM) or continuously from activation until the SPM is stabilized at a target number of rotations, a voltage and temperature monitoring unit monitors the temperature in a disk enclosure unit and the voltage to be applied to an SPM driver. A current-amount limiting value calculating unit calculates an optimum current-amount limiting value not exceeding a rated current of the SPM driver, and a motor controlling unit controls the SPM driver and changes the current to be applied to the SPM so that the current does not exceed this optimum current-amount limiting value.

Abstract: In a storage device, a BEMF control is not performed on a motor and the motor is stopped if the motor is in a BEMF-control possible state. Once the motor has completely stopped, a start-up control is performed on the motor.

Abstract: In a storage device, a BEMF control is not performed on a motor and the motor is stopped if the motor is in a BEMF-control possible state. Once the motor has completely stopped, a start-up control is performed on the motor.