Table of Contents
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 the advantage of slip ring induction motor?
Speeds can be adjusted in the case of slip ring (wound rotor) induction motor by inserting an resistance. Hence slip ring motors are considered as variable speed motors. Slip ring motors have high over loading capacity, smooth acceleration under heavy loads, and no abnormal heating during starting.
How can you increase the phase difference between current and voltage in a slip ring induction motor?
To increase the phase difference the motor is provided with some rings through which high resistance is connected in series with the circuit. Because of this high resistance, he inductive reactance is decreased such that the phase difference the current and voltage is also decreased.
How is a slip ring motor started?
Slip-ring motors are invariably started by rotor resistance starting. Slip-ring motors are invariably started by rotor resistance starting. In this method, a variable star-connected rheostat is connected in the rotor circuit through slip rings and full voltage is applied to the stator winding as shown in Fig: 3.27.
How does a slip ring work?
HOW DOES A SLIP RING WORK? A slip ring passes electrical signals and power across a rotating interface using sliding electrical contacts. These contacts are typically a rotating ring and a stationary brush, or wiper, that slides along the ring surface during rotation.
What is the function of slip ring in motor?
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 rotation while transmitting power or signals.
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.
What type of starter is used in slip ring induction motor?
Rotor resistance starter is used for slip ring induction motors of high ratings.
How do you control the speed of a slip ring motor?
Speed Control by Rotor Rheostat Control With the same rheostat added to the rotor circuit, it is possible to regulate the speed of slip ring motors. The resistance is engaged maximum during starting and slowly cut-off to increase the speed of the motor.
What is the difference between squirrel cage and slip ring induction motor?
The slip ring motor has brushes for transferring the power whereas the squirrel cage motor is brushless. The copper loss in the phase wound motor is high as compared to squirrel cage motor. The efficiency of the slip ring motor is low whereas the squirrel cage motor has high efficiency.
What is difference between commutator and slip rings?
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 function of slip ring 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.
Is slip ring and commutator the same thing?
Physically, a slip ring is a continuous ring, whereas a commutator is segmented. Functionally, slip rings provide a continuous transfer of power, signals, or data. Commutators, on the other hand, are used in DC motors to reverse the polarity of current in the armature windings.
Which starter is used in induction motor?
The star delta starter is used for starting of induction motor above 5 H.P. Auto Transformer – The necessity of reduction of starting current to avoid failure of motor can be effectively done by auto transformer which consists of a single winding.
Which starter is suitable for 3 HP slip ring induction motor?
Solution: Slip ring induction motor Squirrel cage induction motor The rotor resistance starter can be used Rotor resistance starter cannot be used Starting torque is high Starting torque is low Brushes are present Brushes are absent Frequent maintenance is required Less maintenance required.
Which starter is used for slip ring induction motor for high ratings?
For slip ring induction motors with high ratings, a rotor resistance starter is utilised.
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.
Why is squirrel cage induction motor preferred?
Advantages of Squirrel Cage Induction Motor They are low cost. Require less maintenance (as there are no slip rings or brushes) Good speed regulation (they are able to maintain a constant speed) High efficiency in converting electrical energy to mechanical energy (while running, not during startup)Aug 19, 2020.
What are the two types of rotors?
There are two types of induction motor rotors: Squirrel-cage rotor or simply cage rotor. Phase wound or wound rotors.
What is the slip?
Slip is the differentiation between synchronous and asynchronous speed. The difference between the synchronous speed of the electric motor magnetic field, and the shaft rotating speed is slip – measured in RPM or frequency. Slip increases with increasing load – providing a greater torque.
What is the function of the brushes?
A brush or carbon brush is an electrical contact which conducts current between stationary wires and moving parts, most commonly in a rotating shaft. Typical applications include electric motors, alternators and electric generators.
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 are the types of DOL starter?
Direct On Line (DOL) Motor Starter Direct Online Motor Starter – Square D. DOL part -Contactor. DOL part – Termal Overload Relay. Direct On Line Starter – Wiring Diagram. DOL – Wiring scheme.
What are 3 types of motor controls?
There are mainly there are three types of motor control circuits: Direct On Line Starter (DOL starter) Star Delta Starter. Auto Transformer Starter.
What are the types of starter?
What is Motor Starter? Types of Motor Starters and Motor Starting Methods Manual Starter. Magnetic Starter. Direct Online (DOL) Starter. Stator Resistance starter. Rotor Resistance or Slip Ring Motor Starter. Autotransformer Starter. Star Delta Starter. Soft Starter.
