摘要:

Accurate and consistent data on railway-track quality is required from which track-maintenance action can be scheduled. In recent years two recording vehicles have been designed by British Rail: a high-speed track-recording coach (HSTRC) to provide maintenance data for the Civil Engineering Department, and a self-propelled diesel multiple unit used by the Research and Development Division for investigative work. For HSTRC a measuring system was needed which would be reliable under intensive running conditions, and which could be fitted to a standard coach with the minimum of mechanical modification. Conventional multiwheel or multiprobe systems were rejected because of the considerable mechanical complexity of the undergear, in favour of a single-point system using inertial techniques and measuring in the vertical plane through the running wheels and in the horizontal plane through noncontacting optical-scanning equipment. The inertial measuring system uses transducers, including accelerometers, rate gyroscopes and displacement transducers which provide inputs to special-purpose electronic processing networks which provide the required profiles. Onboard computer systems analyse the data to form track-quality estimates which are listed and recorded on magnetic tape for transfer to a central mainframe data bank. Operation of the track-recording coach is controlled by an automatic route-definition procedure using data stored on a central track-route data bank.

DOI:10.1049/ip-b.1984.0012

出版商:IEE    

年代:1984

数据来源: IET

摘要:

A general relation for the instantaneous torque developed by a convertor-fed synchronous motor for known phase current waveform and the field flux distribution is formulated. The influence of these quantities, together with other parameters such as phase number, on torque ripple is discussed with the aid of tabulated predictions for a number of typical cases. Techniques for the achievement of low values of torque ripple are outlined.

DOI:10.1049/ip-b.1984.0013

出版商:IEE    

年代:1984

数据来源: IET

摘要:

A computer-based solution of the equations arising from the application of optimal control theory to a wide-speed-range DC drive reveals the manner in which the control should operate to achieve minimum error-squared performance. An examination of simulated conventional spillover schemes confirms that these are least able to approach the optimal performance in the spillover field-weakening control itself. An alternative field-weakening signal using a mix of speed reference, speed error and current signals is proposed which, simulation indicates, performs more closely to the optimised system in the upper speed ranges. Practical results from a laboratory implementation of this controller suggest that the modest performance improvement is achievable on industrial drives.

DOI:10.1049/ip-b.1984.0014

出版商:IEE    

年代:1984

数据来源: IET

摘要:

A novel two-phase inverter-fed induction-motor drive for essentially constant-speed operation is described, and an example of a 30 W drive is used to demonstrate its performance characteristics and to provide experimental results. The performances of the 30 W motor with two-phase sine wave and inverter supplies are compared, and the speed variation of the inverter drive caused by a supply voltage change is shown to be less than that for a comparable DC motor. A method of predicting the drive performance is presented and is validated by comparisons of theoretical results and test measurements.

DOI:10.1049/ip-b.1984.0015

出版商:IEE    

年代:1984

数据来源: IET

摘要:

The evaluation of steady-state performance and the design methods for variable-speed inverter-fed induction-motor drives suitable for different industrial applications are complex. The nonlinear variation of the drive-system performance indices with frequency and filter parameters, the presence of special performance indices such as pulsating harmonic-torque components, the depletion of breakdown torque, and deterioration in the performance as low frequencies are approached etc. necessitate a completely different approach to the design of these drive systems as compared to the design of conventional single-speed machines. This paper is an attempt to evaluate and compare two types of optimal inverter-fed variable-speed induction-motor drives suitable for two different industrial applications. Digital-computer solutions for the results are presented.

DOI:10.1049/ip-b.1984.0016

出版商:IEE    

年代:1984

数据来源: IET

摘要:

The increasing availability of powerful low-cost microcomputer and graphics facilities should, in the future, allow interactive computer-aided design (CAD) to play an increasingly cost-effective role in the design of variable-speed drives (VSD).In recognition of these developments this paper describes the detailed development of a steady-state current-fed PWM VSD CAD package which offers the designer the possibility of investigating a wide range of PWM operational modes. Demonstrations of the capabilities and potential uses of the CAD package, using typical operational modes, are provided and compared with experimental results from a microprocessor controlled VSD.

DOI:10.1049/ip-b.1984.0017

出版商:IEE    

年代:1984

数据来源: IET