Squirrel-cage rotor

About: Squirrel-cage rotor is a research topic. Over the lifetime, 12602 publications have been published within this topic receiving 142767 citations.

Analysis of direct torque control in permanent magnet synchronous motor drives

Abstract: This paper describes an investigation of direct torque control (DTC) for permanent magnet synchronous motor (PMSM) drives. It is mathematically proven that the increase of electromagnetic torque in a permanent magnet motor is proportional to the increase of the angle between the stator and rotor flux linkages, and, therefore, the fast torque response can be obtained by adjusting the rotating speed of the stator flux linkage as fast as possible. It is also shown that the zero voltage vectors should not be used, and stator flux linkage should be kept moving with respect to the rotor flux linkage all the time. The implementation of DTC in the permanent magnet motor is discussed, and it is found that for DTC using available digital signal processors (DSPs), it is advantageous to have a motor with a high ratio of the rated stator flux linkage to stator voltage. The simulation results verify the proposed control and also show that the torque response under DTC is much faster than the one under current control.

Cause and analysis of stator and rotor failures in three-phase squirrel-cage induction motors

Abstract: The authors attempt to identify the various causes of stator and rotor failures in three-phase squirrel cage induction motors. A specific methodology is proposed to facilitate an accurate analysis of these failures. It is noted that, due to the destructive nature of most failures, it is not easy, and is sometimes impossible, to determine the primary cause of failure. By a process of elimination, one can usually be assured of properly identifying the most likely cause of the failure. It is pointed out that the key point in going through this process of elimination is to use the basic steps of analyzing the failure class and pattern, noting the general motor appearance, identifying the operating condition at the time of failure, and gaining knowledge of the past history of the motor and application. >

Rotary and linear motor

Abstract: A rotary and linear motor having a rotor, a casing and a plurality of stator coils mounted to the interior of the casing spaced from the rotor and radially spaced apart around the rotor. A rotary and linear motor control circuit is operative to receive input data signals and to process these data signals so as to produce a plurality of pulse width modulated output control signals. A multi-phase inverter circuit is coupled to an output of the rotary and linear motor control circuit and is responsive to the plurality of output control signals to drive the stator coils and produce a desired z-axis displacement, z, and rotor angular displacement, θ.

Torque compensated electrical motor

Abstract: An electric motor having a cage pivotally mounted at one end to a post interior a housing by a first bearing and at its other end by a second bearing between the exterior of the cage and the interior of the housing. A first stator is mounted to the interior of the cage and has an output shaft and first rotor interior thereto. A second rotor is mounted to the exterior of the cage and interior a second stator which is mounted interior the housing. The second stator is driven with a control signal which is a function of the measure reaction torque experienced by the first stator to produce a counter torque to balance the reaction torque. A consistency transmitter mounted on the output shaft produces torque on the first stator as a function of the consistency of the material in which it is rotated.

Three-phase self-excited induction generators: an overview

Abstract: Induction generators are increasingly being used in nonconventional energy systems such as wind, micro/mini hydro, etc. The advantages of using an induction generator instead of a synchronous generator are well known. Some of them are reduced unit cost and size, ruggedness, brushless (in squirrel cage construction), absence of separate dc source, ease of maintenance, self-protection against severe overloads and short circuits, etc. In isolated systems, squirrel cage induction generators with capacitor excitation, known as self-excited induction generators (SEIGs), are very popular. This paper presents an exhaustive survey of the literature over the past 25 years discussing the process of self-excitation and voltage buildup, modeling, steady-state, and transient analysis, reactive power control methods, and parallel operation of SEIG.