Posts

Induction Machines

Image
A motor with only a continuous set of armature winding is called an induction motor Such motors are called induction machines because the rotor voltage is induced (which produces the rotor current and the rotor magnetic field) in the rotor wingdings rather than being physically connected by wires.The distinguishing feature of an induction motor is that no dc field current is required to run it. The induction machine is by far the most common type of motor used in industrial, commercial and residential settings. The main reasons for its commonality in these arenas are that it is inexpensive and highly robust. Induction machines can be operated in either generation mode or as a motor (i.e. load).  An induction motor always runs at speed less than synchronous speed. Because the rotating magnetic field produced in the stator will create flux in the rotor and hence will make the rotor to rotate. Due to the lagging of flux current in the rotor with flux current ...
Post a Comment
Read more

Fuse

Image
Fuse is an electrical element that is used to break the circuit in abnormal conditions. Fuse is basically a wire means a wire that has low melting point is called fuse. There are many circuit breakers that is used to break the circuit but fuse is very simple and cheap circuit breaker. Fuse is used in home wiring and many home appliances. It can be easily replaceable. The concept behind fuse is that when a current more than particular limit of that wire (fuse) is passed through fuse, Fuse melts and circuit breaks.
Post a Comment
Read more

The Synchroscope

Image
Synchroscope is used to determine the right instant at which the switch connecting alternator and power station busbars should be closed. this synchronizing process is very cruicial while connecting a new alternator with bus in order to share the load. there are follwing criterias for correct synchronizing which are as follows busbar and incoming machine should have same voltage magnitude. should be in phase. should have same frequency. phase sequence should also be same. The main function of synchroscope is to  show difference  in  phase  and  frequency  of voltages of busbar and the machine which is to be connected. Electro-dynamometer type : It has three limbed transformer one of outer limb is excited by busbar second outer limb is excited by alternator to be connected and the central limb is connected with a lamp.The resultant flux through the central limb is the phasor sum of the fluxes of two outer limbs. The outer ;imb winding are so...
Post a Comment
Read more

AC and DC

Image
DC  means direct current. it has a constant direction intensity of current can vary with time but the direction of movement stays the same at all times this type of sources are produced by solar cells, batteries and thermocouples etc DC power is widely used in low voltage applications such as charging batteries, automobiles etc. alternating current (AC) is an electric current which periodically reverse direction in contrast to direct current which flows only in one direction alternating current magnitude changes with time
Post a Comment
Read more

Electrical Power System

Image
Electric power system is a network of electrical components used to supply, transmit and use electric power. An example of an electric power system is the network that supplies a region's home and industry with power for sizable regions, this power system is called the grid and can be broadly divided into the generators that supply the power, the transmission system that carries the power from the generating stations to the load centers and the distribution system that feeds the power to nearby homes and industries. Small power systems are also found in industry, hospitals, homes and commercial buildings. The majority of these systems relay upon "three-phase AC power' the standard for large scale power transmission and distribution across the modern world. Specialized power systems that do not rely upon the three-phase AC power are found in aircraft, electric rail systems, automobiles etc.
Post a Comment
Read more

How do we measure resistors ?

Image
So there are two ways to measure resistor. 1) Using multimeter In which You connect probe to both end of resistor and switch the knob of multimeter to indicated resistance value. 2) Using colour coding Let suppose  A resistor colored  Yellow-Violet-Orange-Gold  would be 47 * 10^3 Ω with a tolerance of +/- 5%. example (2) A resistor colored  Green-Red-Gold-Silver  would be 52 * 10^-1 Ω with a tolerance of +/- 10%.
Post a Comment
Read more