squirrel cage induction motor torque-speed characteristics

T Nakamuraet al rotor bar end ring Figure 1. Schematic diagram of the rotor windings. motors in electric trains have been fabricated by means of the squirrel-cage-type induction motor in Japan.

The full-load speed is a function of the motor design and power and is usually in the range of 94–99% of the synchronous speed; the difference is the “slip.” 

The principal advantages of the squirrel-cage induction motor are its simplicity of design and robust construction. Its torque/speed and current/speed characteristics are such that, on

Squirrel cage induction motors have mostly been used for their small capacity because the starting torque is smaller than the starting current during start-up.

Our article all about induction motors explains the specifications for all types of induction motors and is a good place to see all the different induction motor characteristics. This article will focus on what needs to be specified for squirrel cage induction motors, which involves phase, speed, torque, and current.

A squirrel-cage motor with this type of rotor construction is called NEMAdesign class D. Its torque-speed characteristic is also shown in Figure 7-26. Deep-Barand Double-Cage RotorDesigns, Both of the previous rotor designs are essentially similar to a wound-rotor motor with a set rotor resistance.

Torque-Speed Characteristics of Three Phase Squirrel Cage Induction Motor Aim, To obtain the torque-speed characteristics (T-N, r) of a three phase squirrel cage induction motor using 1. Variable voltage control 2. Variable voltage variable frequency (V/F) control, Theory,

The construction of squirrel cage induction simple and rugged. Construction of slip ring induction motors needs slip rings, brushes, short-circuiting device, etc. This type of motor has less overhang and better space factor in slots. These motors have the highest overhang and poor space factor in slots. Cost and maintenance are less.

FIGURE 7 Induction motor torque-speed characteristic. The maximum torque that the motor can produce is called the breakdown torque. The motor cannot operate in the steady-state at

Torque Speed Characteristic is the curve plotted between the torque and the speed of the induction motor. · At the maximum torque, the speed of the rotor is 

In a double-cage induction motor, it is assumed that the two cages develop two separate torques. Thus, the total torque developed in the double-cage induction motor is equal to the sum of the two cage torques. The torque-slip characteristics of the two cages and the total torque of the motor is shown in the figure.