摘要:

A new analysis of the induction motor is presented. The machine equations are re-expressed as integral equations, which are solved to yield analytical expressions for the stator and rotor currents and the motor torque. Experimental and theoretical results are compared for both slip-ring and squirrel-cage machines.

DOI:10.1049/ip-b.1982.0033

出版商:IEE    

年代:1982

数据来源: IET

摘要:

Under conditions of variable-frequency supply, the induction motor is known to exhibit regions of lightly damped or oscillatory motion. An investigation of this problem is presented which utilises the integral equation method to solve the machine equations. The instability is explained in terms of the mechanism of parametric action.

DOI:10.1049/ip-b.1982.0034

出版商:IEE    

年代:1982

数据来源: IET

摘要:

A study is presented of the relationships which govern the power flow in induction motors. Equivalent circuits and the Manley-Rowe equations are employed to demonstrate that the frequencies of the current components define the ratios in which supply frequency power is transformed to other frequencies. General relationships are formulated, for the first time, which specify the steady-torque and damping-torque contributions of each current component.

DOI:10.1049/ip-b.1982.0035

出版商:IEE    

年代:1982

数据来源: IET

摘要:

A self-commutating thyristor convertor, fed from a DC supply, drives an induction motor which is provided with excitation capacitors. The frequency of the alternating voltage at the convertor output, and the corresponding speed of the induction motor, can be controlled by varying the values of capacitance, direct voltage, and inverter control angle. The motor operates satisfactorily when loaded. A method of analysis is put forward.

DOI:10.1049/ip-b.1982.0036

出版商:IEE    

年代:1982

数据来源: IET

摘要:

Rare-earth magnet materials offer the possibility of slotless designs for miniature motors. Comparative analyses of slotted and slotless designs are presented for 2-pole permanent-magnet synchronous motors where the magnet has a linear demagnetisation characteristic. Experimental results are given for the magnet field of the slotless design in which the magnet end effect is considered. Results from an experimental slotless motor having a plastics-bonded rare-earth magnet rotor are included.

DOI:10.1049/ip-b.1982.0037

出版商:IEE    

年代:1982

数据来源: IET

摘要:

The input and output conditions for a regenerative thyristor-bridge convertor can be improved in many respects by adopting the controlled flywheeling technique. This paper reports an investigation into the performance of a current-fed inverter and induction-motor system when controlled flywheeling is applied to the supply convertor. It is concluded that the system and motor efficiency, supply-power factor and VAr requirement can be improved, particularly for applications such as traction which use a single-phase supply.

DOI:10.1049/ip-b.1982.0038

出版商:IEE    

年代:1982

数据来源: IET

摘要:

The theory of linear induction motors (LIMs) on steel reaction plates for low-speed applications is presented. The difference in operation of LIMs on steel and aluminium (nonferromagnetic) reaction plates are highlighted using the derived goodness factor for LIMs on steel reaction plates. The specific design parameters for LIMs operating with steel reaction plates are derived. Comparison between the measured ‘dynamic test’ results and predicted results show the validity of the theory for low-speed applications.

DOI:10.1049/ip-b.1982.0039

出版商:IEE    

年代:1982

数据来源: IET

摘要:

Abstract: This paper presents a method of calculation of currents and potentials, excited by the electromagnetic effects of an AC-electrified railway system, along two infinitely long earth-return circuits buried in parallel in the vicinity of the tracks. Inductive and conductive coupling, exists within the railway system, and the earth-return circuit is taken into account, as well as interaction between currents flowing in both underground conductors, whereas the reaction of the conductors' currents on the track current is disregarded. The analysis given is applicable to any railway system in which the tracks may be represented by a single conductor with earth return. The technical applications of the method are illustrated by examples.

DOI:10.1049/ip-b.1982.0040

出版商:IEE    

年代:1982

数据来源: IET

摘要:

Lack of simple methods for predicting some of the losses in a machine in service has limited the theoretical work on additional losses in DC motors with armature current ripple to the prediction of additional copper losses. The additional core losses of a machine fed from the asymmetrical single-phase bridge are predicted from equivalent circuits which contain elements for the core. A method is developed for predicting the additional ‘skin effect’ losses in armature conductors. It is proposed that, by the use of generalised charts developed, the derating of a ‘standard’ bridge-fed DC motor at a specified operating condition can be estimated from look-up tables of additional losses measured on a standard machine.

DOI:10.1049/ip-b.1982.0041

出版商:IEE    

年代:1982

数据来源: IET