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…
A device that converts electrical energy into mechanical energy running at synchronous speed is called Synchronous Motor . Its speed is constant irrespective of load. It is a doubly excited machine because its field winding is ex…
As there is no constructional difference between dc generator and dc motor, similarly, there is no difference between the construction of a synchronous motor and a synchronous generator (alternator). The construction of a synch…
Power Transfer Stages of Induction Motor : An induction motor converts electrical power supplied to it into mechanical power. The various stages in this conversion are called power transfer stages in an induction motor. The 3-ph…
Most of the motors used for household and commercial purposes are induction motors. The use of an induction motor as an induction generator is insignificant. An induction motor has nearly constant speed motor characteristics. Oth…
This test is similar to the no-load test performed on a transformer. The purpose of this test is to determine the no-load losses , no-load power factor, and constants R o and X o of the equivalent circuit. The no-load losses i…
The various types of starters used for starting a 3-phase induction motor are, Full Voltage Starting, Direct-on-line (DOL) starter (full voltage starting). Reduced Voltage Starting, Autotransformer starter. Star-delta starter (re…