After the motor attains maximum speed, DC is applied to the rotor coils. This creates a strong and ongoing magnetic field in the rotor that matches the rotating magnetic field. As a result, the rotor rotates at the same speed as the rotating magnetic field (or synchronous speed). Therefore, there is no slip.
Why does the rotor of an induction motor rotate?
The rotor is a moving component of an electromagnetic system in the electric motor, electric generator, or alternator. Its rotation is due to the interaction between the windings and magnetic fields which produces a torque around the rotor’s axis.
How does an induction motor rotate?
The interaction between the two fields causes the rotor to turn. As the magnetic field alternates between the red and blue coils, it effectively rotates around the motor. The rotating magnetic field makes the rotor spin in the same direction and (in theory) at almost the same speed.
Why does the rotor of the induction motor rotate in the same direction as the rotating magnetic field?
The polarity of these rotor poles is such that they are attracted to the poles of the stator’s magnetic field, so they cause the rotor to follow the rotating magnetic field around in the same direction as the rotating magnetic field in the stator.
What is rotating magnetic field in induction motor?
A rotating magnetic field is a magnetic field that has moving polarities in which its opposite poles rotate about a central point or axis. … Rotating magnetic fields are often utilized for electromechanical applications, such as induction motors and electric generators.
Why do motors rotate?
Large AC motors (used in things like factory machines) work in a slightly different way: they pass alternating current through opposing pairs of magnets to create a rotating magnetic field, which “induces” (creates) a magnetic field in the motor’s rotor, causing it to spin around.
What is the function of a rotor in a motor?
Rotors are the moving part in an Alternator that have permanent magnets that move around the Stator’s iron plates to generate an Alternating Current (AC). Rotors require existing motion to function, so only once the engine or turbine is already running will a Rotor work with a Stator to provide a charge.
Do induction motors have brushes?
AC induction motors have no brushes and have a much longer life expectancy. DC motor speed is controlled by varying the armature current, while AC motor speed control is achieved by varying the frequency of the alternating current, often with a variable frequency drive(VFD).
What are the applications of induction motor?
AC induction motors are the most common electric motors in the world. These simple, reliable and economical motors are found in refrigerators, washing machines and furnaces, as well as conveyors, pumps, winders, wind tunnels and other industrial equipment.
What is 3phase induction motor?
The three-phase AC induction motor is a rotating electric machine that is designed to operate on a three-phase supply. This 3 phase motor is also called as an asynchronous motor. These AC motors are of two types: squirrel and slip-ring type induction motors.
When a motor is short circuited what causes the motor to still rotate?
A magnetic field with the poles facing out is produced in the rotor due to the stator induced current. This causes the rotor (motor shaft) to rotate. As long as the stator is supplied to a stable voltage supply, the motor shaft will continue to rotate. During a short circuit condition the system voltage will decay.
Why does the magnet rotate in an AC motor?
The rotating magnetic field is produced radially around the rotor by the varying currents in the stator windings. The rotating magnetic field induces eddy currents in the squirrel cage’s vertical bars causing it to rotate.
Which type of motor has high starting torque?
DC Series motor has high starting torque. We can not start the Induction motor and Synchronous motors on load, but can not start the DC series motor without load. DC motor has high starting torque.In a series motor the same current flows through the armature and the field winding.
What are the advantage of rotation magnetic field?
Rotating field makes the overall construction very simple. With simple, robust mechanical construction and low inertia of rotor, it can be driven at high speeds. So greater output can be obtained from an alternator of given size. If field is rotating, to excite it from external dc supply two slip rings are enough.
What is the working principle of induction motor?
The motor which works on the principle of electromagnetic induction is known as the induction motor. The electromagnetic induction is the phenomenon in which the electromotive force induces across the electrical conductor when it is placed in a rotating magnetic field.
How does a rotating motor work?
Thus, every brushed DC motor has AC flowing through its rotating windings. Current flows through one or more pairs of brushes that bear on the commutator; the brushes connect an external source of electric power to the rotating armature. … The force between the two magnetic fields tends to rotate the motor shaft.