Electrical Articles Archive
Basic concept calorific value of fuel
Fuel is defined as any combustible material, obtained in bulk, containing carbon as a major constituent and when burnt in presence of oxidant evolves heat which can be economically used for domestic and industrial heating or power
What is 3 ph induction motor
3 phase inductions motor consists of two main parts Stator Rotor The stator is stationary frame and rotor is rotating armature. The stator is made up of made up a large number of stampings these stampings are
What is a failure of shunt generator to build up?
Causes of failure of voltage build-up or armature heating: No residual magnetism Without any residual magnetism, voltage build-up cannot start. Due to again in transportation, the machine may lose residual magnetism. This difficulty can be overcome by
Effect of variation of rotor resistance
Rotor resistance can be changed in case of wound rotor induction motor with help of external resistances connected and to brushes through slip rings provided a supply voltage and load remains constant. The starting torque hence speeds
What is squirrel cage rotor
In this type of rotor, the rotor drum is provided with a number of circular holes, which are parallel to the shaft. Solid copper or aluminium bars are placed in these holes and all bars are welded
Working principle of sodium vapour lamp
Scientists have long been familiar with fact high luminous efficiency could be obtained by the use of sodium resistant glass, the sodium vapour lamp has now reached the practical stage. Working and construction Principally the sodium vapour
What is wound rotor induction motor
The rotor windings are star-connected like a three-phase star connected transformer. Rotor winding is present inside rotor drum. Rotor drum is placed on the motor shaft. Motor shaft carries three slip rings which are circular in shape
Why is single phase induction motor not self-starting?
When single-phase AC supply is given to stator winding. It produces alternating flux.i.e. which alternates along one space axis only. It is not synchronously revolving (or rotating) flux, as in case of 3 phase stator winding, the
What is split phase induction motor
Split phase inductions motor: resistance star induction run Two winding are connected in parallel to supply to make 1 phase induction motor self-starting. One is main winding and other is staring winding. both these winding are 900
Explain role of back of emf in controlling armature current
Back of emf in controlling armature current [ back emf as a current register] voltage eqn for dc motor is Ia(V-Eb)/(Rb) Back EMF is the system in the coil of an electric motor that opposes the current