In a single-phase as well as three-phase transformer the windings are placed on the core structure which is made up of a laminated steel core. This core structure which supports the two windings of the transformer is placed insid…
What is Leakage Flux in a Transformer ? We know that all the flux linked with primary winding is also linked with the secondary winding. But, in the actual transformer the total flux created does not link with the primary and se…
Why Sumpner's Test or Back to Back Test? For a transformer, the temperature rise is an important factor to be noted before making it into operation. The temperature of a transformer changes in proportion to the load. Because…
Electricity generated at all the power plants is alternating i.e., ac, in order to generate direct current i.e., dc, a commutator is used to convert the generated ac supply into dc supply. Hence, an electrical generator with a co…
The performance (efficiency, regulation, losses) of a transformer is best judged if the following four parameters of its equivalent circuit are known, The equivalent resistance R 01 is referred to as primary, and the equivalent…
The blocked rotor test, it is quite opposite of the no-load test of the induction motor. Usually in transformer tests, if we want to find the behavior of a transformer on loading and on no-load, it can be done by using open circu…
What is Ideal Transformer? An ideal transformer is one that has no losses i.e., its windings have no resistance, there is no magnetic leakage, and hence it has no iron and copper losses. It may, however, be noted that it is impo…
As we know that most electrical power plants are located far away from the load centers. Because the electrical energy generated by thermal and hydro or any other power plants are located at a distance from the consumers. To tran…
Necessity of Starting a Three-phase Induction Motor : In a 3-phase Induction motor, the magnitude of rotor induced emf depends upon slip. The equation for Rotor current of induction motor is given by, At starting, the magnitud…
As we know that a single-phase induction motor is not a self-starting motor. In order to make it self starting, changes are to be done to the construction. Let us see the construction and working principle of the shaded pole indu…
In a dc motor, speed will depend on armature current and field voltage. So to control dc motor speed, field voltage or armature current should be changed. In a dc series motor or universal motor, the speed is indeterminate and i…
The phasor diagram of a synchronous motor is shown below. From the phasor diagram, let, V = Supply voltage/phase I a = Armature current/phase R a = Armature resistance/phase α = Load angle Φ = Power factor angle. Input Power …
We know that in a synchronous generator or alternator when the conductors of the rotor cuts the alternating magnetic flux lines produced by the stator or field winding an EMF will induce in the rotor conductors (according to the …
The performance characteristics of a synchronous motor are obtained by v-curves and inverted v-curves. Synchronous machines have parabolic type characteristics (the graph drawn is in the shape of parabolic). If the excitation i…
Synchronous Condenser or Synchronous Capacitor : If a synchronous motor is on no-load and over-excited (E b > V) then the current drawn by it leads the voltage by nearly 90°. The phasor diagram of the motor at no-load is sh…
