Controlling of AC Lamp Dimmer through Mobile phone

The project aims in designing a system which is capable of controlling the AC lamp dimming operation through Mobile phone using DTMF technology. As the world gets more and more technologically advanced, we find new technology coming in deeper and deeper into our personal lives even at home. Home automation is becoming more and more popular around the world and is becoming a common practice.
The process of home automation works by making everything in the house automatically controlled using technology to control and do the jobs that we would normally do manually. It is much easier to install home automation in a house while it is still being built, since you have the ability to put things inside the walls to save space. Though, people who have houses already built can still have home automation done in a less intrusive ways.

The controlling device of the whole system is a Microcontroller. DTMF decoder and Triac to which AC lamp is connected are interfaced to the Microcontroller. The user need to call the mobile phone present in the system which will be in auto answer mode. When the call got lifted, the user need to press the predefined intensity keys assigned to control the lamp dimming operation of AC lamp. This system also has an LCD display which shows the intensity level of the lamp. The Microcontroller used in the project is programmed using Embedded C language. A Triac and optically isolated diac based circuit controls the intensity of the high voltage 230volts lamp. This system also employs a zero crossing detector for smooth operation of lamp intensity. This project consists of a Microcontroller that takes input from mobile phone and processes the request. Then it processes the data and takes necessary action and updates the status on LCD. The optical isolation system safeguards the microcontroller-based system fro

m high voltages.

Electrical Interview Questions and Answers,

Electrical interview question:why, when birds sit on transmission lines or current wires doesn't get shock?
Answer:Its true that if birds touch the single one line (phase or neutral) they don't get electrical shock... if birds touch 2 lines than the circuit is closed and they get electrical shock.. so if a human touch single one line(phase) then he doesn't get shock if he is in the air (not touching - standing on the ground if he is standing on the ground then touching the line (phase) he will get a shock because the ground on what we standing is like line (ground bed - like neutral)। and in the most of electric lines the neutral is grounded..so that means that human who touch the line closes the circuit between phase and neutral.

Electrical interview question:what is meant by armature reaction?

Answer:The effect of armature flu to main flux is called armature reaction. The armature flux may support main flux or opposes main flux.

Electrical interview question:what happen if we give 220 volts dc supply to d bulb r tube light?

Answer:Bulbs [devices] for AC are designed to operate such that it offers high impedance to AC supply. Normally they have low resistance. When DC supply is applied, due to low resistance, the current through lamp would be so high that it may damage the bulb element.

Electrical interview question:Which motor has high Starting Torque and Staring current DC motor, Induction motor or Synchronous motor?

Answer:DC Series motor has high starting torque. We can not start the Induction motor and Synchronous motors on load, but can not start the DC series motor without load.

Electrical interview question:what is ACSR cable and where we use it?

Answer:ACSR means Aluminium conductor steel reinforced, this conductor is used in transmission & distribution.

Electrical interview question:What is vaccum currcuit breaker.define with cause and where be use it Device?

Answer:A breaker is normally used to break a ciruit. while breaking the circuit, the contact terminals will be separated. At the time of seperation an air gap is formed in between the terminals. Due to existing current flow the air in the gap is ionised and results in the arc. various mediums are used to quench this arc in respective CB's. but in VCB the medium is vaccum gas. since the air in the CB is having vaccum pressure the arc formation is interrupted. VCB's can be used upto 11kv.

Distributed Control System (DCS) in Power Plant

Usage of Single Computer for control of all the process variables of plant would result in the loss of control action in the plant if failure occurs to the master single computer. Also, time required for accessing large data, processing the received data and controlling of the entire plant by single computer will takes more time and slows down the process system

Distributed Control System:

In distributed control system, different process systems in the plant will have their control system loop. Thus in distributed control system number of individual control loops will be present. Several Microprocessors were employed at the different locations of the power plant and dedicated to provide services for individual process system of the plant and monitor and control each process of the plant (This is unlike SCADA master-slave architecture, in DCS all microprocessors will be masters). Every processor at different locations of the plant acquire the data from its process system, process the received data and provides control functions and also stores the required data. These microprocessors are connected to each other and also connected to the station master computer through which operator can see the information and take control actions if necessary. Control system in power plant will have distribution in both topologically and functionally. Functional distribution such as operation of boiler side values, fans, turbine values, boiler oil firing, boiler coal firing for carrying out such different functions Microprocessors are distributed.

Topological distibutuion is achieved by employing closed loops for operation of different equipment such as boiler steam A equipment, boiler steam B equipment, boiler oil firing AB/CD/EF elevations will have dedicated control loop

This type of distribution results in increase in speed and reliability of the control system.