In this mode of operation, supply is given to the stator sides and the motor always rotates below the synchronous speed. The induction motor torque varies from zero to full load torque as the slip varies. The slip varies from zero to one. It is zero at no load and one at standstill.
What is normal slip of an induction motor?
Because of this speed difference, the motor rotates at a speed slightly slower than the synchronous speed. Slip is normally expressed in percentage. Slip of a power induction motor is 2 to 3% when the motor is operated under the rated load.
What are motor characteristics?
Electric motor speed-torque characteristics may be classified into three main groups:
- Absolutely Hard (flat) Speed-Torque Characteristic: A characteristic exhibiting no change in speed with change in load torque. …
- Hard Speed-Torque Characteristic: …
- Soft Speed Characteristic:
What are induction motors used for?
Single-phase induction motors are used extensively for smaller loads, such as household appliances like fans. Although traditionally used in fixed-speed service, induction motors are increasingly being used with variable-frequency drives (VFD) in variable-speed service.
What is the basic 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.
What happens if the slip of induction motor is one?
Slip = 1, means that rotor is stationary. Negative value of slip in induction motor can be achieved when the rotor speed is more than the synchronously rotating magnetic flux.
What is the importance of slip in induction motor?
The slip of the motor is kept low when the induction motor is running at no-load. The small slip produces the small torque on the motor. The value of the induction motor slip is adjusted according to the requirement of the driving torque at the normal working condition.
Why is the DC motor preferred over AC motor?
AC motors are generally considered to be more powerful than DC motors because they can generate higher torque by using a more powerful current. However, DC motors are typically more efficient and make better use of their input energy.
What are the types of motors?
Types of Electric Motors
- AC Brushless Motors. AC brushless motors are some of the most popular in motion control. …
- DC Brushed Motors. In a DC brushed motor, brush orientation on the stator determines current flow. …
- DC Brushless Motors. …
- Direct Drive. …
- Linear Motors. …
- Servo Motors. …
- Stepper Motors.
What are characteristics of dc motor?
Generally, three characteristic curves are considered important for DC motors which are, (i) Torque vs. armature current, (ii) Speed vs. armature current and (iii) Speed vs.
What is difference between induction motor and synchronous motor?
A three phase Synchronous motor is a doubly excited machine, whereas an induction motor is a single excited machine. The armature winding of the Synchronous motor is energized from an AC source and its field winding from a DC source. The stator winding of Induction Motor is energized from an AC source.
Which motor is used in fan?
Which type of winding is induction motor?
The most used winding type for medium-size induction motors is a double layer winding with pitched winding step, for example pitched for two stator slots (Fig. 2). Significant advantage of the aforementioned winding is a smaller mass of inserted copper because of shortest winding-ends.
What is the 3 phase 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.
What is advantage and disadvantage of induction motor?
A single phase induction motor, unlike a 3 phase induction motor, does not have a self starting torque. Auxiliaries are required to start a single phase motor. During light load conditions, the power factor of the motor drops to a very low value.
What is the principle of a motor?
The principle of an electric motor is based on the current carrying conductor which produces magnetic field around it. A current carrying conductor is placed perpendicular to the magnetic field so that it experiences a force.