Abstract: A motor driving apparatus capable of detecting during operation a ground fault and a phase-to-phase short circuit by distinguishing one from the other is provided while minimizing an increase in cost. The sum of three-phase AC currents supplied from a three-phase AC power supply to an AC/DC converter is detected by a current sensor. When overcurrent is detected by an overcurrent detector, if the sum of the currents detected by the current sensor is zero, it is determined that the fault is a phase-to-phase short circuit, but if the sum is not zero, it is determined that the fault is a ground fault.

Abstract: Disclosed is a motor driving apparatus in which provisions are made so as to easily isolate the cause of a fault in the event of the occurrence thereof. The voltage and current in each phase of the AC power being supplied to a converter are detected, and the most recently detected data are stored in a power supply monitoring unit for a predetermined period of time. If an alarm occurs in the converter, inverter, or controller, the data currently held in the power supply monitoring unit are recorded in a recording unit. By displaying the thus recorded data, one can easily identify whether the cause of the alarm is due to the power supply or the motor driving apparatus itself.

Abstract: A motor driver for a machine tool, which comprises a fan motor, configured to drive a cooling fan for cooling a radiator or the interior of the motor driver, estimates a rate of heat release within a heating element or the motor driver, based on information obtained from a motor current detector used for motor control or from an input current detector of the motor driver, and adjusts a fan motor power supply voltage to control a rotational speed of the fan motor in accordance with the estimated heat release value.

Abstract: Signals from a plurality of sensors (vibration sensors, temperature sensors, and humidity sensors) disposed at places on a machine are input through a communication circuit to a numerical controller that controls the machine. The numerical controller uses vibration information, temperature information and humidity information obtained from these sensors to determine whether the machine is in an abnormal state.

Abstract: Disclosed is an insulation deterioration detection device that can accurately detect insulation deterioration in multiple motors by a simple circuit configuration. When detecting insulation deterioration, one end A of a smoothing capacitor is connected via a first switch to ground, and the other end B is connected via a second switch to motor windings; in this condition, link voltage is measured by a voltage measuring circuit provided in a converter unit, and the measured link voltage value is transmitted to a microcomputer in each inverter unit via serial communication. Current flowing via motor insulation resistance Z1, Z2 is measured by a current measuring circuit provided in each inverter unit, and the microcomputer calculates the value of the insulation resistance Z1, Z2 from the link voltage value and the current value.

Abstract: A motor driving apparatus for driving and braking a motor equipped with a brake comprises a motor/brake driving DC power supply which is used both as a motor driving power supply and as a brake driving power supply, wherein when the motor/brake driving DC power supply is being used as the motor driving power supply, a voltage conversion circuit via which a voltage supplied from the motor/brake driving DC power supply is applied to the brake feedback-controls the voltage applied to the brake. This configuration serves to reduce the loss (due to temperature rise) in the brake coil of the motor being driven to move a robot arm.

Abstract: Disclosed is an insulation deterioration detection device that can accurately detect insulation deterioration in multiple motors by a simple circuit configuration. When detecting insulation deterioration, one end A of a smoothing capacitor is connected via a first switch to ground, and the other end B is connected via a second switch to motor windings; in this condition, link voltage is measured by a voltage measuring circuit provided in a converter unit, and the measured link voltage value is transmitted to a microcomputer in each inverter unit via serial communication. Current flowing via motor insulation resistance Z1, Z2 is measured by a current measuring circuit provided in each inverter unit, and the microcomputer calculates the value of the insulation resistance Z1, Z2 from the link voltage value and the current value.

Abstract: A servo amplifier for a robot capable of avoiding an excessive capacity for dealing with a regenerative power to achieve downsizing, cost reduction and energy saving of the device. A servo amplifier for driving servomotors of a robot to perform an operation using an electric power from a power source. The servo amplifier comprises a changeable converter connected with the power source and a plurality of inverters electrically connected with the converter and the servomotors. The changeable converter is selectively provided as a converter having a regenerative function of returning a regenerative power generated in the servomotors to the power source, or a converter having a regenerative function of discharging the regenerative power through a resistor, depending on conditions of the operation by the robot.

Abstract: A die cushion drive system provided with a servo motor serving as a source of drive power for a die cushion of a press machine and a power circuit with a regeneration function which regenerates energy from the servo motor and returns it to an AC power supply, whereby it is possible to power the die cushion drive system by a servo motor and return the regenerated energy of this servo motor to the power source so as to save on energy.

Abstract: A motor insulation deterioration detection device wherein a capacitor provided in a power supply section is utilized as a power supply for motor insulation deterioration detection, with provisions made to be able to detect insulation resistance regardless of the value of the voltage developed across the capacitor. The motor insulation deterioration detection device includes: a first contact which connects one end of the capacitor to ground; a second contact which connects the other end of the capacitor to a motor coil via a detection resistor; a unit which, using the detection resistor, detects a current flowing through a closed circuit formed by the first contact, capacitor, second contact, detection resistor, motor coil, and ground; a unit which detects the voltage developed across the capacitor; and a unit which calculates the insulation resistance value based on the current detection value and the voltage detection value.

Abstract: A motor driving apparatus for driving and braking a motor equipped with a brake comprises a motor/brake driving DC power supply which is used both as a motor driving power supply and as a brake driving power supply, wherein when the motor/brake driving DC power supply is being used as the motor driving power supply, a voltage conversion circuit via which a voltage supplied from the motor/brake driving DC power supply is applied to the brake feedback-controls the voltage applied to the brake. This configuration serves to reduce the loss (due to temperature rise) in the brake coil of the motor being driven to move a robot arm.

Abstract: An insulation-resistance degradation detecting device capable of selecting one of a plurality of motors and detecting its insulation-resistance degradation. A power source unit is connected with a plurality of motor drive amplifiers which drive two motors, individually. The motor is selected by selecting means, and a contactor S1 or S2 is turned on. When a smoothing capacitor C of the power source unit reaches a predetermined voltage after an electromagnetic contactor is turned off, contactors SW1 and SW2 are turned on, whereupon one end of the smoothing capacitor C, contactor SW2, resistors R1 and R2, contactor S1 or S2, coil of the motor, insulation resistor Rx of the motor, grounds G2 and G1, contactor SW1, and the other end of the smoothing capacitor C form a closed circuit. The voltage of the smoothing capacitor C is applied to this closed circuit. A potential difference across the detection resistor R1 is obtained and compared with a reference voltage to detect insulation-resistance degradation.

Abstract: A motor driver capable of detecting the insulation deterioration of a motor easily and inexpensively is disclosed. The voltage supplied from an AC power supply (1) is rectified by a first rectifying circuit (D1 to D6) and smoothed by a capacitor (C) in a power supply unit (6). The output voltage of the power supply unit (6) is converted into an AC voltage of a frequency and a motor (M) is driven by a motor drive amplifier (8). Elements (R1, C2, R11, C21) are connected between at least one of the positive electrode (4) and the negative electrode (5) of the output line (4, 5) of the power supply unit (6) and the ground (G2, G4). An insulation deterioration circuit (10, 11, 12) detects at least one of the voltage between the elements and the current flowing through the elements.

Abstract: The drive of the motor is stopped, the electromagnetic switch contacts are switched OFF, and thereafter the first and second contact points are closed to form a closed circuit of the smoothing capacitor, second contact point, first and second resistors, motor coil, ground 1, ground 2, first contact point, and smoothing capacitor. Charging voltage of the smoothing capacitor is applied to the closed circuit. If an insulation resistance of the motor deteriorates, a current flowing through the closed circuit is increased. The increase of the current is detected by means of the potential difference across the first resistor R1 in the closed circuit, to detect insulation resistance deterioration of the motor.

Abstract: A motor driving apparatus capable of drivingly controlling a plurality of inverter units with a single motor driving command from a motor control unit, and thereby control a large-capacity motor or the like. The motor control unit sends out a single motor driving command (torque command) S. An intermediary unit obtains motor driving commands S×A1 to S×A4 for the inverter units by multiplying the motor driving command S by each of coefficients A1 to A4 set in advance. The inverter units are fed with the motor driving commands S×A1 to S×A4 individually and drive a single motor. Since the motor is driven by the total current supplied by the inverter units, the motor can generate a large torque. The motor control unit only needs to generate a single motor driving command S, and hence only needs to operate a single processing part. Hence, the motor control unit can generate and send out motor driving commands for other motors to drive them.

Abstract: A circuit system that includes a sensor circuit for a sensor that detects the state of a motor is provided in an inverter unit for driving the motor. A 0V of the circuit system is connected with a shield braid of a shielded cable that connects the sensor circuit and the sensor. Further, the shield braid of the shielded cable is connected to an earth plate.

Abstract: In the motor driving system, a unit to predict the separation of the wire is built into the power semiconductor module thereby to predict that the time of separation of the wire is approaching before the actual separation of the wire. Thus, the time to replace the power semiconductor module used for power devices such as the motor driving system is clarified to prevent an operation failure of the motor driving system from occurring. The power semiconductor module (1) has a power semiconductor chip (2) mounted thereon, and the power semiconductor chip (2) includes a main circuit wire (4) and a dummy wire (5) connected to the electrode (3) of the power semiconductor. The dummy wire is set to a lower connection strength than the main circuit wire.

Abstract: The drive of the motor is stopped, the electromagnetic switch contacts are switched OFF, and thereafter the first and second contact points are closed to form a closed circuit of the smoothing capacitor, second contact point, first and second resistors, motor coil, ground 1, ground 2, first contact point, and smoothing capacitor. Charging voltage of the smoothing capacitor is applied to the closed circuit. If an insulation resistance of the motor deteriorates, a current flowing through the closed circuit is increased. The increase of the current is detected by means of the potential difference across the first resistor R1 in the closed circuit, to detect insulation resistance deterioration of the motor.

Abstract: A die cushion drive system provided with a servo motor serving as a source of drive power for a die cushion of a press machine and a power circuit with a regeneration function which regenerates energy from the servo motor and returns it to an AC power supply, whereby it is possible to power the die cushion drive system by a servo motor and return the regenerated energy of this servo motor to the power source so as to save on energy.

Abstract: In a control apparatus, a “characteristic value calculation” block calculates a characteristic value (such as amplitude value, offset value, or waveform distortion for each phase of two-phase sinusoidal signals optically input from an encoder, or phase difference between the two phase signals) for each of the two-phase sinusoidal signals, and an “alarm detection” block checks the presence or absence of an excursion outside a predetermined allowable range and, if such an excursion is detected, produces an alarm indication or the like. Each time the “present characteristic value” is input, a “characteristic value comparison” block compares it with “previous characteristic values”, and analyzes the result of the comparison. That is, the difference between the present value and each previous data is calculated, and the largest amount of variation (with plus or minus sign) is obtained; if this amount is larger than a predetermined value, a signal indicating an “imminent failure” is output.