Electrical engineering

Many of us know that, in electrical power generation the frequency must be kept constant for satisfactory operation of power system. But, the question is, why the frequency is to made constant?  Before this, let us first understand the basic operation of the alternator. Operation of alternator: An alternator (synchronous generator) is a machine which converts mechanical energy into electrical energy at a particular voltage but at a constant frequency. The rotor part consist of field winding and stator part consist of armature winding. The field winding is excited with D.C supply. The turbine is mechanically coupled with the rotor to give the mechanical power input to the alternator. Now, when rotor rotates the flux due to field winding cuts armature conductors and according to the faraday's law of electromagnetic induction, an emf is induced in the armature conductors. The frequency of induced emf is given by: So, to generate constant frequency, the machine must always be driven at

Which are the must conditions to be fulfilled for the operation of an Electric Motor? An electric motor is an electro-mechanical energy conversion device i.e converts electrical energy into mechanical energy. The motors are generally classified as: D.C motors. A.C motors. Operating principle It works on the principle of lorent'z force law i.e " Whenever a current carrying conductor placed inside a magnetic field experiences a force". Conditions for the operation of an electric motor For any type of motor, the two conditions are must to be satisfied. They are as follows: There must be the interaction of two magnetic fields. Both the magnetic field must be stationary with respect to each other i.e relative speed between two fields must be zero. The number of stator poles and rotor poles must be same. What happens if this conditions are not satisfied? The operation of an electric motor depends on the presence of electromagnetic torque. The expression for electromagnetic torq

How to measure an inductance of a coil without using LCR meter? To measure the inductance of a coil , one can use a LCR meter. But, measuring the inductance of the coil without LCR meter is also not a difficult task. We can do it in a simple way by using some mathematical expressions. Consider a coil as shown above whose inductance is to be measured and then follow these steps:- 1) Take a battery and an ammeter and connect them in series with coil. Take a voltmeter and measure the battery voltage. The ammeter will give current through the coil. The voltmeter will give voltage across the coil. Then find resistance of the coil by using mathematical expression 2) Disconnect the battery and connect an A.C source of some frequency "f" hz across the coil. Then using voltmeter and ammeter reading, find the impedence of the coil by using mathematical expression Now, as we have the impedence of the coil and resistance of the coil, we can now find the inductive reactance of the coil us