Three Phase Induction Machine

Introduction

The three-phase induction machine is the most widely used rotating machines. An induction machine offers an almost constant speed within its normal operating range when operated off a constant-voltage, constant-frequency, and electric power source. Economically, the cost of purchasing these machines can be considered very low, and they require little maintenance. However, controlling the speed of this type of machine is difficult and can be considered very expensive. In this paper, several topics related to the squirrel cage rotor, working principles, speed control, as well as simple examples will be discussed.

Squirrel Cage Rotor

Construction:
Squirrel cage rotor is considered as an example of a

Currents in the bars are set up by induced voltages which create a field in the rotor core. Torque is developed as a result of the rotor field reacting with the stator field, hence causing the rotor will rotate (Chu, Chung, Thomas, Tuttle & Lee, 2003). The stator synchronous speed is always faster than the speed of the rotor. Motors are designed so that there is an increased efficiency in a high-speed range. With high-speed the motor will have an increased torque in a low-speed range.

Main characteristics:
The speed regulation characteristic of the squirrel-cage induction motor can certainly be considered an advantage. The speed machine performance can be measured by using percent slip. When measuring the speed machine performance, the synchronized speed of rotating field of the stator has to be used and due to the operating frequency, the synchronous speed will also be constant. However, at full load, the number of revolutions per second due to slipping behind of the rotor can be obtained when the stator field is rotating, and the rotor speed is

Motors play an important role in many areas of industry such as air conditioning, water pumping, and many others. The simplicity of AC motor makes it widely used in various fields. AC cooling fans are used as it can supply a stream of air to help maintain a certain temperature or to cool down the temperature.
The fan work in the same way that a thermostat interacts with an air conditioning unit so as to maintain the temperature. The AC fan will supply the machine with an increased air once the computer/sensor detects a warmer environment. It will also help to maintain A certain value of temperature, so that the device can function at the ideal levels. Figure 2, represent a flow chart of the working mechanism of the AC cooling fan.

Figure 2: Logic flow chart of AC cooling fan

The processing unit (CPU) chips used in most electronic devices (including sensors) can reach very high temperatures when the machine is working, and taking away the heat requires a lot of effort to pass air over the CPU. The heat sink is designed so that it conducts heat. The bottom of the sink is flat to provide the large contact area with the CPU. The upper part has several fins with numerous air channels between them. The surface area of this section is increased by these fins, thus increasing cooling efficiency and also to increase the amount of heat that is taken away from the