[en] The steady-state theory of the motor is presented. The main parameters of a 1.5 Mw induction motor are calculated. The starting torque is proportional to the conductor normal resistance which can be adjusted to the operational requirement by selecting an appropriate high resistivity conductor matrix. 4 refs

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[en] Stepper Motor Controlling System is developed using electro-mechanical and digital electronic components such as stepper motor driver and stepper motor, and Control Processing Unit (CPU) respectively. Purpose of the system is to control angular movement of stepper motor from a point to another point. This movement can be either for Clock Wise (CW) or Counter Clock Wise (CCW) direction. Stepper motor can be controlled through parallel port that was ready made allocating in CPU. This port had a role as a communication bridge between stepper motor and CPU. It allows the digital signals that have been setup up from CPU to operate the stepper motor. (author)

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[en] A variable-speed axial-gap motor with a stator consisting of four liquid helium cooled superconducting electromagnets (two pole pairs) was built and proof tested up to 608 rpm in November 1990 as a tool for joint industry-laboratory evaluation of coils fabricated from high-temperature oxide superconductors. A second rotor was fabricated with improved material, winding configuration, and wire type, and the drive system was modified to eliminate current spiking. The modified motor was characterized to design speed, 188 rad/s (1800 rpm), to acquire a performance baseline for future comparison with that of high-temperature superconducting (HTS) wire. As it becomes commercially available, HTS wire will replace the low-temperature electromagnet wire in a stator modified to control wire temperatures between 4 K and 77 K. Measurements of the superconducting electromagnetic field and locked rotor torque as functions of cryocurrent and dc current through two phases of the rotor, respectively, provided data to estimate power that could be developed by the rotor. Back emf and parasitic mechanical and electromagnetic drag torques were measured as functions of angular velocity to calculate actual rotor power developed and to quantify losses, which reduce the motor's efficiency. A detailed measurement of motor power at design speed confirmed the developed power equation. When subsequently operated at the 33-A maximum available rotor current, the motor delivered 15.3 kW (20.5 hp) to the load. In a final test, the cryostat was operated at 2500 A, 200 A below its critical current. At rotor design current of 60 A and 2500 A stator current, the extrapolated developed power would be 44.2 kW (59.2 hp) with 94% efficiency

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