weewew

Comments

Post a Comment

Popular posts from this blog

Electrical Circuit Theorems for Circuit Analysis

Electrical Circuit Theorems: To solve problems in electrical networks, there are number circuit theorems have been developed like (1) Kirchhoff's laws (2) Superposition theorem (3) Thevenin theorem (4) Norton Theorem (5) The maximum power transfer theorem In this post we have listed all these theorems. We believe that this post will serve as a ready reference for you. Kirchhoff's laws: (a) Current Law:  At any junction in an electric circuit the total current flowing towards that junction is equal to the total current flowing away from the junction, i.e. I =0 (b) Voltage Law:  In any closed loop in a network, the algebraic sum of the voltage drops (i.e.products of current and resistance) taken around the loop is equal to the resultant e.m.f. acting in that loop. Superposition Theorem: In any network made up of linear resistances and containing more than one source of EMF, the resultant current flowing in any branch is the algebraic sum of the currents that would flow in that ...
Read more

Electrical Machines Viva Questions and Answers: Part-1

Electrical Machines Viva Questions and Answers [1] How to reverse the direction of rotation of dc motor? To reverse direction of rotation of dc motor, either direction of main field produced by the field winding is reversed or direction of the current passing through the armature is reversed. By changing the direction of current passing through the field winding,the direction of the main field can be reversed. [2] What are the functions of yoke? what is the choice material for the yoke? It serves the purpose of outer most cover of the dc machine. so that the insulating material get protected from the harmful atmospheric environmental like noise, dust and various gases like SO2, acidic fumes etc. It provides mechanical support to the poles. It forms a part of the magnetic circuit. It provides a path of low reluctance for magnetic flux. It is prepared by using cast iron. For large machines, rolled steel, cast steel, silicon steel is used which provides high permeability. [3] Why generato...
Read more

Power system Analysis

Q: Write the most important mode of operation of power system and mention the major problems encountered with it.  Symmetrical steady state is the most important mode of operation of power system. Three major problems are encountered in this mode of operation. They are,  1) Load flow problem  2)  Optimal load scheduling problem 3) Systems control problem Q: Why power flow analysis is made? Power flow analysis is performed to calculate the magnitude and phase angle of voltages at the buses and also the active power and reactive voltamperes flow for the given terminal or bus conditions. The variables associated with each bus or node are, a. Magnitude of voltage |V|  b. Phase angle of voltage δ  c. Active power, P d. Reactive voltamperes, Q Q: What is power flow study or load flow study?  The study of various methods of solution to power system network is referred to as load study. The solution provides the voltages at various buses, power flowing in Vari...
Read more