IEE Proceedings B - Electric Power Applications

The authors establish a simplified theoretical model for variable-reluctance stepping motors systems, based on the linearisation of the motor's dynamic torque-producing characteristics about an arbitrary working point. It is shown that, by representing the torque as contours in the speed/switching angle plane, unambiguous stability limits for open and closed-loop operation are clearly defined. The... View full abstract»

A design method for L- and T-connected tapped-winding capacitor motor is presented. This method is fundamentally based on the balanced conditions at the full load for high speed connection. Performance equations for a tapped-winding capacitor motor are derived by the method of the two-phase symmetrical component. Characteristics of the motor, obtained by the suggested design method, are discussed ... View full abstract»

The authors introduce an unusual form to DC-to-DC convertor using an unregulated inverter, which is transformer coupled to a high frequency cycloconvertor. They give a brief description of a prototype system and present some practical waveforms. The main content of the paper is devoted to the development of a modulation law for the square wave cycloconvertor, which is done by comparison with conve... View full abstract»

Certain ferrites, referred to as temperature-sensitive magnetic semiconductors (TMS), exhibit marked temperature dependence in both magnetic and electrical fields. The temperature dependence of TMS resistance is similar to a semiconductor thermistor at low voltages. At higher voltages, three states are observed in the symmetric bidirectional characteristics: a cut-off state; a negative resistance ... View full abstract»

The authors review the disturbance mechanisms which can exist between chopper-controlled DC traction equipment and low-frequency track circuits which commonly operate at 50 or 60 Hz. They show that disturbance exists due to the various modes of chopper circuit operation, as well as to small mains-frequency AC voltage ripple sources which exist in the traction supply. Models are presented which def... View full abstract»

The authors set out to state clearly the influence of saturation on torque production and energy flow in a doubly salient machine. A comparison is made between the performances of a series of switched reluctance motors, which are identical in all respects except for the iron used. The differences include: the use of ideal nonsaturating iron; the introduction of saturating material in the pole face... View full abstract»