Table of Contents
Working of Slip Ring Induction Motor When a three-phase power supply is given to the stator of a three-phase motor. An RMF is produced which rotates in the air gap present in the stator. This RMF cuts the rotor windings I,e whenever a current-carrying conductor is influenced by a magnetic field an emf will be induced.
What is the principle of slip ring induction motor?
This motor runs on the principle of Faraday’s law of electromagnetic induction. When a stator winding is excited with an AC supply, the stator winding produces magnetic flux. Based on faraday’s law of electromagnetic induction, the rotor winding gets induced and generates a current of magnetic flux.
What is slip ring in 3 phase induction?
A wound-rotor motor, also known as slip ring-rotor motor, is a type of induction motor where the rotor windings are connected through slip rings to external resistance. Adjusting the resistance allows control of the speed/torque characteristic of the motor.
What is principle of 3 phase induction?
The stator of an induction motor consists of a number of overlapping windings offset by an electrical angle of 120°. When the primary winding or stator is connected to a three phase alternating current supply, it establishes a rotating magnetic field which rotates at a synchronous speed.
What is the method of starting a 3 phase slip ring induction motor?
The three-phase induction motor may be started by connecting the motor directly to the full voltage of the supply. The motor can also be started by applying a reduced voltage to the motor. The torque of the induction motor is proportional to the square of the applied voltage.
Is slip ring a commutator?
A commutator is a specialized slip ring typically used on Direct Current motors and electrical generators to transfer electrical power between the stationary housing and the rotating armature with the added purpose of reversing the electrical current direction.
Why slip rings are used in induction motor?
In a version of the AC induction motor referred to as a wound rotor motor, slip rings are used not for transferring power, but for inserting resistance into the rotor windings. As the slip rings turn with the rotor, the brushes maintain constant contact with the rings and transfer the resistance to the rotor windings.
What is the difference between slip rings and commutator?
The main difference is that commutator is used for the conversion of AC to DC. Slip rings are used in AC motors to provide a continuous transfer of power whereas the commutators are used in DC motors to reverse the polarity of the current in the armature windings.
What is the purpose of slip rings?
“A slip ring is an electromechanical device that allows the transmission of power and electrical signals from a stationary to a rotating structure. A slip ring can be used in any electromechanical system that requires unrestrained, intermittent or continuous rotation while transmitting power and / or data.
What is slip formula?
If the revolving magnetic flux’s synchronous speed & the speed of rotor are Ns & Nr in the motor, then the speed among them can be equivalent to (Ns – Nr). So, slip can be determined as. S = (Ns – Nr) / Ns.
What are the advantages of 3 phase induction motor?
Unlike synchronous motors, a 3 phase induction motor has a high starting torque, good speed regulation and reasonable overload capacity. An induction motor is a highly efficient machine with full load efficiency varying from 85 to 97 percent.
What are the main parts of 3 phase induction motor?
The stator of the three-phase induction motor consists of three main parts : Stator frame, Stator core, Stator winding or field winding.
What are the applications of 3 phase induction motor?
Application of 3-Phase Induction Motors Pumps and submersible. Pressing machine. Lathe machine. Grinding machine. Conveyor. Flour mills. Compressor. And other low mechanical power applications.
How does a 3 phase induction motor start?
DOL Starter – It is a direct online starter consists of one-way switch simultaneously operates on each phase of the three-phase stator winding. The overload release of this switch protects the motor against overcurrent and No-volt release of this switch protects the motor from sudden three phase supply failure.
Which is the cheapest method of starting 3 phase induction motor?
Direct on line starter is the simplest and inexpensive methods among all other methods for starting induction motor. DOL starter is connected directly between the supply and motor terminal.
Which starting method is best for induction motor?
1. Direct On Line Starter It is simple and cheap starter for a 3-phase induction motor. The contacts close against spring action. This method is normally limited to smaller cage induction motors, because starting current can be as high as eight times the full load current of the motor.
Are slip rings used in DC motor?
As we know, a slip ring is a device that is used to transmit the power and electrical signal from a stator to a rotor. Thus, we can say the slip ring is used in a device which requires the transmission of power to the rotating structure. In a d.c electric motor, the commutators are used instead of slip rings.
Why are slip rings used in AC generators?
The function of slip ring in an AC generator is that these are the hollow rings that are connected to the ends of the armature coil. They help in rotation of the coil. A slip ring in an electric motor is used an electrical joint to transmit power. It acts as a bridge between a still component and a rotating element.
What is slip in DC motor?
Slip is the differentiation between synchronous and asynchronous speed. An AC (Alternating Current) induction motor consists of a stator and a rotor and the interaction of the currents flowing in the rotor bars and the rotating magnetic field in the stator generates the torque that turns the motor.
What type of starter is used in slip ring induction motor?
Rotor resistance starter is used for slip ring induction motors of high ratings.
What is the difference between induction motor and slip ring motor?
In Squirrel cage induction motors the rotor is simplest and most rugged in construction. In slip ring induction motors the rotor is wound type. In the motor the slip rings, brushes are provided. Compared to squirrel cage rotor the rotor construction is not simple.
