The load has a counteracting torque that resists the torque supplied by the motor. That resistance to the motor torque is seen electrically by the rotor as additional resistance in the rotor circuit in series with the actual very low resistance of the rotor bars.
What is load in a motor?
For example, when a motor is turning a water pump, the water pump is the load. The water pump is the mechanical device that the motor must move. This is the definition of a motor load. As with electrical loads, the mechanical load connected to a dc motor affects many electrical quantities.
What is full load in induction motor?
Synchronous and full load speed of amplitude current (AC) induction motors
|Number of Poles||Frequency (Hz, cycles/sec)|
What is load test of induction motor?
The load test on induction motor is performed to compute its complete performance i.e. torque, slip, efficiency, power factor etc.
What happens when load increases in induction motor?
If the load on the induction motor is increased the current will increase to deliver the demanded power. The slip of the motor will increase with an increase of loading on the motor, and the speed of the motor will decrease accordingly. A 3 phase induction is running at 1740 rpm on a 60 Hz supply.
What is type of load?
Types of loads acting on a structure are:
Imposed loads. Wind loads. Snow loads. Earthquake loads. Special loads.
Which type of load is applied on motor?
The three main electric motor load types are: Variable-torque loads – eg fans and pumps where the speed varies. With this type of load, reducing the speed of the motor by even a small amount can save a lot of energy. Constant-torque loads – eg conveyors, screw and reciprocating compressors, and crushers.
What is 120 in motor speed formula?
The equation for calculating synchronous speed is: S = 120 f/P speed = constant (120) times frequency of power source (60 Hz) divided by number of poles used in the motor (P).
What is full load torque in 3 phase induction motor?
Torque of a three phase induction motor is proportional to flux per stator pole, rotor current and the power factor of the rotor.
What is the full load speed?
The speed at which a motor will turn (in rpm) when the rated voltage is supplied.
What is no load test of induction motor?
The no-load test of an induction motor is similar to the open-circuit test of a transformer. The motor is not connected from its load, and the rated voltage at the rated frequency is applied to the stator to run the motor without a load. The 2-wattmeter method measures the input power of the system.
Why no load test is performed in induction motor?
As the name suggest no load test is performed when rotor rotates with synchronous speed and there is no load torque. … This test gives the information regarding no-load losses such as core loss, friction loss and windage loss. Rotor copper loss at no load is very less that its value is negligible.
What is synchronous speed?
: a definite speed for an alternating-current machine that is dependent on the frequency of the supply circuit because the rotating member passes one pair of poles for each alternation of the alternating current.
What is the function of induction motor?
An induction motor or asynchronous motor is an AC electric motor in which the electric current in the rotor needed to produce torque is obtained by electromagnetic induction from the magnetic field of the stator winding. An induction motor can therefore be made without electrical connections to the rotor.
What is rotor induced emf?
3 Rotor induced e.m.f. and current. The rate at which the rotor conductors are cut by the flux, and hence their induced e.m.f., is directly proportional to the slip, with no induced e.m.f. at synchronous speed (s = 0) and maximum induced e.m.f. when the rotor is stationary (s = 1).
Why does motor current increase with load?
The electrical loads are normally connected in parallel, whenever the load(impedance) is increased means the additional load (or you can say impedance) is connected in parallel to the existing load. The parallel combination always reduces the equivelent impedance. Hence the current is increases.