Equivalent Circuits and Their Application in Designing Shaded Pole Motors

Improved estimation of induction machine parameters

Expressions for the saturation factors for the leakage reactance of induction motors with skewed rotors are derived. Saturation is taken into account by the effect of the combined slot-, zigzag-, and skew-leakage flux on the permeances of the flux leakage paths. Curves of saturation factors and leakage reactance of a standard motor are compared with test.

Saturation Factors for Leakage Reactance of Induction Motors with Skewed Rotors

The paper presents a method for synthetising the equivalent-circuit parameters of double-cage induction motors to attain specified levels of starting, accelerating, breakdown torque and running performance. New equations are derived, avoiding certain approximations which have commonly been made hitherto, and these equations are used to relate the equivalent-circuit parameters to the motor performance. A new synthesis procedure is then developed, based on these equations and relationships. The procedure includes a number of sections which are essentially iterative, and it is consequently most conveniently embodied in a digital-computer program. Since the reduction of leakage reactances owing to magnetic saturation is an important factor in motors with arduous starting duties, a method is proposed for taking this effect into account. Using, as a starting point, an approximate representation of the shape of typical curves of leakage reactance against current, equations are derived to represent the saturation effect in a form which isconveniently incorporated in the computer program. Only two additional items of input data are required to specify the saturation effect, these being the current at which saturation commences and the ratio of saturated to unsaturated starting currents. The successful operation of the synthesis procedure is demonstrated by a number of examples, including some in which the computed design is compared with a prior manual design to the same specification.

Design synthesis of double-cage induction motors

Significant improvements in the performance of the triac voltage control of split-phase fan motors can be achieved by increasing the rotor resistance and winding ratio. These improvements include a reduction in the maximum main winding current and an increase in the speed stability throughout the control range. The analysis of the motor performance with triac control of the main winding voltage only, is based on independent consideration of the functional (supply) frequency and harmonic content of the applied chopped sinusoidal voltage. Excellent agreement with measured results is obtained and comparision with variac control can be made directly.

The design optimisation of a split phase fan motor with triac voltage (speed) control

The Equivalent Circuit of the Capacitor Motor

Saturation Effect of Leakage Reactance

A Design Method for Capacitor Start Motors

IN AN A-C series motor, the flux pulsation in the field is predominantly at line frequency. The field iron loss can be computed easily and represented by a loss component in the magnetizing current. However, due to the rotation of the armature, the gap flux is rotating relative to the armature, as well as pulsating. The armature iron loss depends on both the line frequency and the speed. Part of the iron loss is supplied electrically by a loss component in the magnetizing current, while the remaining part is supplied mechanically as a load on the shaft. The accurate calculation of motor performance is dependent upon the correct determination and also the correct allocation of these losses.

Armature Iron Losses in Series Motors

POWER COMPANIES are usually particular about the starting current and running power factor of an induction motor. However, induction-motor manufacturers cannot possibly supply a motor much better in these respects than the present National Electrical Manufacturers' Association Design C standards, even though ideal materials should be discovered in the future.

http://ieeexplore.ieee.org/iel5/4763772/5060012/05060064.pdf

Sheldon S. L. Chang

Papers

The Equivalent Circuit of the Capacitor Motor

Saturation Effect of Leakage Reactance

A Design Method for Capacitor Start Motors

Armature Iron Losses in Series Motors

General Theory of Multiple Cage Induction Motors