Abstract: A casing for electrical equipment has a drip-proof structure and includes a first plate and a second plate. The first plate has a plurality of first openings and a plurality of tongue-shaped louvers disposed in the respective first openings. Each louver has a lower end continuous to the first plate. The upper end side of each louver is folded to a back side of the first plate, The second plate is disposed on a front of the first plate. The second plate has a plurality of second openings each having a smaller area than each first opening. The first and second plates are overlapped with each other so that the first and second openings communicate with each other, forming a louver structure. The first and second plates are coated in the overlapped state with a result that a gap between them is filled with a paint.

Abstract: A stored electric power discharging circuit for an inverter device includes a group of series resistors configured to be connected in parallel to a plurality of main circuit capacitors in a normal operation, a voltage stabilization circuit configured to stabilize interterminal voltages of the respective main circuit capacitor according to a divided voltage of the series resistors during the normal operation, and a control switch having a control input and configured to cut the direct connection between the series resistors at a time of power-off, thereby breaking a voltage stability state of the main circuit capacitors by the voltage stabilization circuit.

Abstract: A voltage balancing circuit includes (n?1)-number of voltage stabilization circuits configured between k-th reference nodes of n-number of groups of resistances and k-th output nodes of the n-number of groups of main circuit capacitors respectively where 2?k?n. The k-th voltage stabilization circuit is configured in such a manner that the first transistor is connected via a first resistance to a (k?a)-th output node serving as the source node and the second transistor is connected via a second resistance further connected to a (k+b)-th output node serving as the destination node, where 2?k?n, 1?a?k?1 and 1?b?n+1?k.

Abstract: An inverter device includes an inverter main circuit to which a load is connected, an input unit configured to receive an input operation by a user, a connector into which a hot-pluggable external storage device is insertable, and a control unit configured to control writing of a log to the external storage device inserted into the connector. When the external storage device is inserted in the connector, the control unit switches the external storage device to a connected state in which the log is allowed to be written to the external storage device. When the input unit receives the input operation during the connected state of the external storage device, the control unit stops writing of the log to the external storage device and switches the external storage device to a disconnected state in which the external storage connector is removable from the connector.

Abstract: A motor control device includes an inverter driving an electric motor, a vector controller determining an output frequency and a command output voltage to drive the inverter, a speed controller determining a torque command value, a current command calculation unit and an inertia moment estimation unit obtaining a load torque estimate value and estimating inertia moment that is a combination of inertia moment of a motor rotor and inertia moment of a load apparatus, based on a deviation between an acceleration/deceleration torque output value obtained by subtraction of the load torque estimation from motor torque and an acceleration/deceleration torque estimate value obtained by multiplying a variation amount in the speed estimate value per unit time by an inertia moment estimate value. The speed controller is configured to be capable of adjusting a control parameter based on an inertia moment estimate value estimated by the inertia moment estimation unit.

Abstract: A stored electric power discharging circuit for an inverter device includes a plurality of series resistors configured to be connected in parallel to a plurality of main circuit capacitors in a normal operation, a voltage stabilization circuit configured to stabilize interterminal voltages of the respective main circuit capacitors according to a divided voltage of the series resistors during the normal operation, and a control switch having a control input and configured to divide energization current supplied to the series resistors at a time of power-off, thereby breaking a voltage stability state of the main circuit capacitors by the voltage stabilization circuit.

Abstract: A voltage balancing circuit includes (n?1)-number of voltage stabilization circuits configured between k-th reference nodes of n-number of groups of resistances and k-th output nodes of the n-number of groups of main circuit capacitors respectively where 2?k?n. The k-th voltage stabilization circuit is configured in such a manner that the first transistor is connected via a first resistance to a (k?a)-th output node serving as the source node and the second transistor is connected via a second resistance further connected to a (k+b)-th output node serving as the destination node, where 2?k?n, 1?a?k?1 and 1?b?n+1?k.

Abstract: A motor control device includes an inverter driving an electric motor, a vector controller determining an output frequency and a command output voltage to drive the inverter, a speed controller determining a torque command value, a current command calculation unit and an inertia moment estimation unit obtaining a load torque estimate value and estimating inertia moment that is a combination of inertia moment of a motor rotor and inertia moment of a load apparatus, based on a deviation between an acceleration/deceleration torque output value obtained by subtraction of the load torque estimation from motor torque and an acceleration/deceleration torque estimate value obtained by multiplying a variation amount in the speed estimate value per unit time by an inertia moment estimate value. The speed controller is configured to be capable of adjusting a control parameter based on an inertia moment estimate value estimated by the inertia moment estimation unit.

Abstract: An inverter device includes an inverter main circuit to which a load is connected, an input unit configured to receive an input operation by a user, a connector into which a hot-pluggable external storage device is insertable, and a control unit configured to control writing of a log to the external storage device inserted into the connector. When the external storage device is inserted in the connector, the control unit switches the external storage device to a connected state in which the log is allowed to be written to the external storage device. When the input unit receives the input operation during the connected state of the external storage device, the control unit stops writing of the log to the external storage device and switches the external storage device to a disconnected state in which the external storage connector is removable from the connector.