Induction Motor Protection System Circuit and Its Working

The electric motor is a most crucial drive in the modern era of automation. These motors are used in various industrial applications. But these motors can be protected from the different mechanical and electrical faults for helping their purposes. This article discusses about a protection system for induction motor from emerging faults using embedded microcontroller. The induction motor experiences various kinds of electrical faults such as over voltage or under voltage, unbalanced voltage, overload, earth fault, phase reversing and single phasing. Due to these faults, the windings in the motor gets heated which lead to reduce the life of the motor. The faults in motor may occur due to faults in the motor or in the driven plant, conditions executed by the external power supply n/w.The degree of the induction motor depends on the applications and costs of the motor.

Induction Motor Protection System
Induction Motor Protection System

What is an Induction Motor?

Induction motor or asynchronous motor is the most commonly used motor in various applications. Because, these motors always run at a lower speed than synchronous speed.Synchronous speed can be defined as, the speed of the magnetic field which is rotating in the stator. Induction motors are classified into two types based on the sort of input supply such as single phase induction motor and three phase induction motors. Induction motors are classified into four types namely; split phase induction motor, capacitor start induction motor, capacitor start capacitor run induction motor and shaded pole induction motor.And also based on the type of rotor three phase induction motors are classified into two types such as wound type, slip ring motor squirrel cage motor.

Induction Motor
Induction Motor

Working Principle

In a DC motor, supply is required to be given for the rotor winding as well as the stator winding. But in this motor only an AC supply is fed with the stator winding.

Alternating flux is formed around the stator winding because of the AC supply. This flux rotates with synchronous speed that is called as RMF (Rotating Magnetic Field). An induced emf can be caused by the comparative speeds between rotor conductors and stator RMF. According to the Faraday’s electromagnetic induction law, the rotor conductors are short circuited, and later the rotor current is generated because of an induced emf. That’s why these motors are called as induction motors.

Induction Motor Working Principle
Induction Motor Working Principle

Now, the current which is induced in the rotor will also create an alternating flux around it. According to Lenz’s law, the direction of induced rotor current is, it will tend to oppose the cause of its production.

Induction Motor Protection System Circuit and Its Working

The main goal of this project is to design an induction motor protection system for guarding the motors from any faults happening from single phasing and over voltage conditions.

Induction Motor Protection System Circuit by Edgefxkits.com
Induction Motor Protection System Circuit by Edgefxkits.com

The induction motor is an essential device in various industrial applications. These motors work on 3-phase supply and a standard temperature to keep the loads at preferred conditions. But; if any phase goes lost or there is a growth in the temperature of the windings it harms the motor. Thus, the proposed system helps to give a protection to the motors in the industries by eliminating the power to the electric motor immediately if any of the phases misses out of the 3-phases, or if the motor’s temperature exceeds the threshold value.

The proposed system uses 3-phase power supply, where 3 single-phase transformers are allied to it. The project has a set of operational amplifier which is used as comparators for relating input voltages. A thermistor is used to sense the temperature of the induction motor by connecting with the body of the induction motor. This motor is functioned by switching the main relay, which is worked by another set of relays by detecting single phasing & over temperature conditions.

Induction Motor Protection System Project Kit by Edgefxkits.com
Induction Motor Protection System Project Kit by Edgefxkits.com

In future, this project can be developed by using current sensors and phase-sequence sensor for protecting the overloads and also the motor from applying wrong phase sequence.

Induction motor Protection system from single phasing, over voltage, under voltage, overheating and phase reversal provides the smooth running of the induction motor expands its lifetime and also efficiency. Generally, these faults occur when supply system is violating its rating. When the motor is running at rated current, load and voltage then these faults will not be generated. Generally, the smooth running of the motor can be depends on the supply voltage under the set limit & load which is determined by the motor should also be under the stated limit.

Therefore, this is all about induction motor protection system project and its working. We hope that the information which is provided in this article is very useful for you for a better understanding of this concept. Furthermore, any help in implementing electrical and electronic projects or others, you can approach us by commenting below.

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8 Comments

  1. Hi.Can anyone provide me circuit diagram for this project.I have to submit my project next month.

  2. In this project which type of microcontroller ic used?

  3. any type of starter is needed or not needed?

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