Electricity has changed the world. life becomes easier after the invention of electricity. no work can take place without electricity. In this evolution, electric machines also played their major role and serving humans effortlessly. Electrical machines are the electromechanical conversion device. These machines are divided into two categories
- Dynamic
- Static
Dynamic machines contain stator and rotor as the major part. these are called dynamic because they have moving parts in them. Dynamic machines are further classified into
- Electric motor
- Electric generator
Static machines contain no moving parts in them. A transformer is a static device, not an energy
conversion but changes the magnitude of voltage/current of an AC quantity. The working principle of the transformer is mutual induction. the main two types of transformer are step-up transformer and step-down transformer. a step-up transformer increases the voltage and a step-down transformer decreases the voltage at the output.
Electric motor
It is a conversion device that converts electrical energy into mechanical energy. The motors are divided into three types AC motors, DC motors, special motors.
Ac motors
as clear from name use AC quantity for the working of motors. these are divided into two types as induction motors(asynchronous) and synchronous motor.
Induction motors are singly excited motors. which means they only require a single AC quantity for their operation. the field windings are excited by the AC supply rotating magnetic field produces which produces the current in the rotor of the motor and the rotor starts rotating. Induction motors are also called a generalized transformer. two types of rotors are used in the motor, squirrel cage rotor and wound rotor. the induction machines are classified into single-phase and three-phase induction motor. these motors are mainly used in the industries.
Synchronous motors are doubly excited motors. they use DC supply for the field excitation and AC quantity is produced. the speed of the rotor is synchronized with the frequency of applied the applied current. synchronous motors are used where constant speed is required. these are works on the law of electromagnetic induction. if the motor is unable to maintain synchronous speed, it will eventually stop.
synchronous motors are also classified into single-phase and three-phase synchronous motors.
DC motors
Separately excited DC motor this motor use external DC source for the excitation of the field winding. so the armature has no relation with the external DC source.
Series excited motor in these types of motors field winding is in series with the armature winding. the current in the field winding depends on the armature current, so this series field is also called a current operated field.
Shunt excited motor in these motors the field winding is in parallel with the armature winding called a shunt. the voltage across both armature and shunt is the same, which means the voltage across the field is depends on the armature voltage. this shunt field is also called voltage-operated field.
Compound motor this motor use both series winding and shunt winding. is the shunt winding is in parallel with armature then the motor is short shunt compound motor, but if the shunt field is in series with armature then the motor is long shunt compound motor.
PMDC permanent magnet DC motors use a permanent magnet in place of a field winding.
Special motors
besides these motors, there are some special motors like servo motors used in Arduino projects, stepper motors, brushless DC motor, hysteresis motor, etc.
Electric Generator
An electrical generator is a device that converts mechanical energy into electrical energy. the prime mover is rotated by turbines in thermal power plants, hydropower stations, or using wind energy.
there are two types of generators AC generators and DC generators. DC generator or dynamo converts mechanical energy into electrical energy. when the rotor rotates in the magnetic field the alternating current is produced in the rotor. this alternating current then further converted into DC with the help of commutator. these generators are also classified into single-phase and three-phase generators.
AC generators are also of two types of induction generator and synchronous generator, but a mainly synchronous generator is used for the generation of AC supply. The synchronous generator is also called because it converts mechanical energy to AC.
In this article, I only covered the basics from this you can't understand the working of all the different machines. So from now onwards, we gonna discuss all these machines in detail.
0 Comments