摘要:

The paper presents measurements and calculations of the stray loss in several solid-rotor versions of British Rail's tubular-axle induction motor (TAIM) of 150 kW capacity. The use of a large airgap and of narrow slot openings as means of reducing the loss to manageable levels are investigated, and it is found that the large gap approach is more successful.

DOI:10.1049/ip-b.1982.0026

出版商:IEE    

年代:1982

数据来源: IET

摘要:

Some aspects of the design of a toroidal-stator, permanent-magnet, salient-pole-rotor type of limited rotation, double-acting rotary actuator are examined. Curves are presented which show how important design parameters are affected by the airgap size. Analysis leading to the prediction of stator self inductance, for a variety of types of rotor configuration, is presented. Test results are compared with theoretical predictions.

DOI:10.1049/ip-b.1982.0027

出版商:IEE    

年代:1982

数据来源: IET

摘要:

The operation of a group of parallel-connected, nominally identical switching transistors is prone to difficulties owing to spread in switching times. The fastest and slowest transistors in the group are liable to fail through excessive power dissipation. A method of regulating transistor operation is described in which the application and removal of base current is phase controlled to compensate for differences in switching speeds. The transistors therefore appear identical, in so far as the emitter currents within a group of devices rise and fall in synchronism during switching transitions. This approach offers certain advantages over more conventional solutions to the problem of parallel operation, by allowing higher switching frequencies to be used and by allowing the transistors to pass nearly full-rated current.

DOI:10.1049/ip-b.1982.0028

出版商:IEE    

年代:1982

数据来源: IET

摘要:

To realise the full output potential of a PWM inverter, it is necessary to make the transition from a PWM output waveform to a square-wave output. This is usually achieved by dropping pulses from the PWM waveform, which results in step changes in the output voltage. It is shown that, generally, pulse dropping is unavoidable except with one particular type of inverter circuit. A waveform generation strategy is proposed for this type of inverter which allows the transition from PWM to square-wave output to be made without voltage-waveform discontinuities of any kind.

DOI:10.1049/ip-b.1982.0029

出版商:IEE    

年代:1982

数据来源: IET

摘要:

If a stepping motor is operated under closed-loop control, then, for maximum torque production, the switching angle must vary with the stepping rate. This variation is investigated theoretically for a variablereluctance stepping motor and a low-cost method of implementing a speed-dependent switching-angle control is described. Experimental results indicate that this type of control enables the motor to produce a high torque at low speeds, but to still operate at speeds up to the pull-out rate.

DOI:10.1049/ip-b.1982.0030

出版商:IEE    

年代:1982

数据来源: IET

摘要:

The performance characteristics of a small-scale wind-power system with a separately or self-excited DC generator are analysed and experimentally confirmed. The relations between output and wind speed are derived, and their effect on performance is discussed.

DOI:10.1049/ip-b.1982.0031

出版商:IEE    

年代:1982

数据来源: IET

摘要:

A theory of control in state space is applied to an electrotechnical process associating an asynchronous motor and a static convertor. The object is to realise current regulation for an induction machine. The process is inherently nonlinear and a classic regulator cannot ensure the same performances over all the operating range. A mathematical model of the process to be controlled is presented and a compensator determined. An observer and the desired regulation are chosen through the imposition of the system dynamics in a closed loop.

DOI:10.1049/ip-b.1982.0032

出版商:IEE    

年代:1982

数据来源: IET