Abstract: Disclosed herein is a method of controlling the current of a high-speed Switched Reluctance Motor (SRM) using an inverter circuit including a first switching element, a second switching element, a first diode, a second diode and a reactor, wherein the first switching element and the first diode, the second diode and the second switching element are connected to a bridge circuit, and one end of the reactor is connected to the junction of the first switching element and the first diode, and the remaining end of the reactor is connected to the junction of the second diode and the second switching element; and excitation mode, free-wheeling mode-1, the excitation mode, and free-wheeling mode-2 are sequentially performed in a unit period T, and, when the control is terminated, demagnetization is performed.

Abstract: Embodiments of the present invention include a composite electromechanical machine which can operate as a motor, a generator (including dynamo or alternator), or any combination thereof. In an aspect, the present composite electromechanical machine comprises at least a double-sided magnetic plane (e.g., rotor or stator) to form two rotor/stator pairs, together with a controller to configure the multiple rotor/stator pair. The controller can configure or convert the multiple rotor/stator pairs into motors, generators, or nonoperation, and also can change the windings characteristics of the magnetic planes. The controller can add new functionality and characteristics to the present composite electromechanical machine. Other embodiments can also be included.

Abstract: A motor having windings normally energizable by electric power from an AC power supply is stopped in case of an emergency such as a failure of the AC power supply. The motor has a rotor rotatably supported by magnetic bearings out of contact therewith. The windings of the motor are normally energized by a motor driver with the electric power from the AC power supply. When the AC power supply fails, a battery power supply supplies electric power to the windings of the motor to brake the rotor and also to the magnetic bearings to continuously operate the magnetic bearings. A switching controller which includes timers and logic circuit elements controls times to supply the electric power from the battery power supply to the windings of the motor and the magnetic bearings. The switching controller has timers for controlling the times.

Abstract: A hard disk drive having a plurality of disks mounted on the rotor of a current limited, electronically commutated dc motor. Windings on the stator of the motor are divided into serially connected run and start sections and first and seconds drive circuits are provided to operate the motor by alternatively enabling the first drive circuit to pass currents serially through the two sections of the winding and enabling the second drive circuit to pass currents through only the run sections of the windings. During spin up of the disk drive to operating speed, the first drive circuit is enabled and the second drive circuit is disabled to drive the disks to the speed at which the back emf limits on the acceleration of the motor using both sections of the windings reduces the acceleration to the maximum acceleration achievable at the current limit using the run sections alone. Spin up is then completed by enabling the second drive circuit and disabling the first drive circuit.

Abstract: In a drive system for a grinding mill the load torque plus frictional torque may increase considerably as a loaded mill is inched from its rest position and will suddenly decrease when the load tumbles or cascades. The applied torque or driving torque must increase at a corresponding rate and should also decrease when the load cascades. If the applied torque exceeds by a significant amount the load torque plus frictional torque, a destructive hammering will occur in the gear train and this will be generally proportional to the excess of applied torque for a synchronous motor drive. The drive system has a DC source which is commutated by a commutating device to provide a low frequency stepped alternating voltage to the stator windings of the synchronous motors of the drive system for inching. The output of the DC source has an alternating current component which varies as the difference between the applied torque and the load torque plus frictional torque.

Abstract: In the propulsion system of an electric locomotive, a-c wayside power is converted to direct current for the traction motors by means of several phase-controlled rectifying bridges having serially connected outputs. The bridges are controlled sequentially so that their respective output voltages are introduced in stages as increasing amounts of voltage are required at the motors of an accelerating locomotive. Normally certain thresholds of speed need to be attained before the second bridge, and later the third bridge, are permitted to be phased on. Means is provided for changing the bridge control sequence in response to faults in the first or second bridges.