What are the characteristics of 3-phase induction motor?
Three-phase currents flowing within the stator create a rotating magnetic field which induces a current and consequent magnetic field in the rotor. Rotor torque is developed as the rotor slips a little behind the rotating stator field. Unlike single-phase motors, polyphase induction motors are self-starting.
Which of the following is the torque speed characteristic typical of an induction motor?
The induction motor torque-speed characteristic gives information on the dependence of induced mechanical torque on mechanical speed. Sometimes this characteristic is called torque-slip characteristic, where slip is defined as speed relative to synchronous speed expressed as a fraction of synchronous speed.
What are the characteristics of torque?
Torque is proportional to voltage squared and the current is proportional to the voltage. So, if the stator voltage is reduced the speed reduces and similarly if the stator voltage is increased the speed also increases.
What is speed torque?
Torque relates to the rotational force of an electric motor while speed refers to the rate that the motor can rotate. This means that torque is associated with rotational force while speed relates to the rate of rotation which can be calculated by examining the RPMs, or revolutions per minute.
What do you understand by slip and torque speed characteristics of induction motor?
The graph plotted between the torque and slip for a particular value of rotor resistance and reactance is known as torque-slip characteristics of the induction motor. From the eqn. (1), it can be seen that if R2 and X2 are kept constant, the torque depends upon the slip ‘s’.
What is speed control of induction motor?
Induction motor speed control is a process of manipulating currents in an induction motor to regulate speed. While often used in fixed frequency applications, induction motors are popular for variable frequency applications such as industrial drives and electric vehicles.
What is torque speed curve?
The torque speed curve of a load is a plot showing its torque requirement on the y- axis versus the speed on x-axis. It’s the torque requirement of the load from zero speed to full speed. Its application/load specific and varies with different load types.
What is characteristics induction motor?
1. Characteristic of Induction Motor. ¥ The induction motor is classified into a single-phase motor and a three-phase motor according to the using power source. This motor always uses both auxiliary winding and condenser not only when starting but also during operation.
How is speed and torque related?
The relation between torque and speed are inversely proportional to each other. The torque of a rotating object can be mathematically written as the ratio of power and angular velocity.
What are the characteristics of induction motor?
Rotating Speed and Torque 2.40 shows the characteristics of induction motors. When a motor is designed in such a way that impedance of the aluminum conductor of the rotor is reduced, its efficiency is increased in a high-speed range.
What is the relation between torque and speed in induction motor?
The relation between torque and speed are inversely proportional to each other.
What is the relation between torque and speed in three phase induction?
It gives the information about variation in the motor torque with the change in its speed. As the torque of three-phase induction depends upon its speed but the relationship between them cannot be expressed by a simple equation.
Why is a three phase induction motor called a constant speed motor?
Due to this, three phase induction motor is practically said to be ‘constant speed’ motor as drop in speed from no load to full load is not significant. The unstable region of operation is shown dotted in the Fig.1.
What is the starting torque of an induction motor at 0?
At N = T s, the motor stops as it can not produce any torque, as induction motor can not rotate at synchronous motor. At N = 0, the starting condition, motor produces a torque called starting torque. For low slip region, i.e. speeds near the region is stable and the characteristics is straight in nature.
Why does the slip rate of an induction motor depend on torque?
The rotational speed N of an induction motor, and thus the slip, depends on the operating point, which depends on a load torque requirement (so, for a motor, if torque is higher, speed is lower). The same is true for a generator; an equilibrium point is reached when the torque demand on the shaft is fulfilled by the generator prime mover.