Mind map
Principles of electrical
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Principles of electrical
- How does contactor works ? Contactor works by connecting on one side by live and other side by neutral when energised it creates a magnetic affect which pulls connections in making contact when low voltage or no voltage. Occurs it automatically let's go and the circuit breaks.it's a safety feature
- How a storage heater works correct It used economy 7 tariff which is cheaper at night ,it uses heating elements to heat special heat retaining bricks which are also heavily insulated they retain the heat and release it slowly throughout the day by means of radiation and convection/electricity is used to heat thermal bricks in the heater. This heat can then be released as required
- How much power in star connection compared to delta? Both capable of giving 230/400v,equal to each other but star also provides neutral and earth whereas delta doesn't
- How do you improve the power factor? There are three methods of improving the power factor 1.Connecting capacitors across the loads will improve the power factor, as the capacitor has the opposite effect to an inductor. 2. The second way to improve power factor is to connect capacitors across the total supply at the intake position. This is called bulk correction. 3.The third method is to use a synchronous motor, which can be run with a leading power factor this will improve the lagging power factor. This is expensive and is only used in large industries.
- 2 types of losses in a transformer correct? Iron loss and copper
- How many connections in a star/delta starter correct Star-delta starters must be connected to three-phase motors, which have six connection points at the motor.
- Low pressure mercury lamp operating It's uses electricity to excite mercury vapour.the excited mercury atoms produce short wave ultra-violet light that then cause a phosphor to fluoresces, producing visible light Applications They are used in commercial environments, such as offices where large areas needs to be illuminated other in domestic and industrial Purpose of the ballast? It's provides extra kick, start and starts regulating the current.
- High pressure mercury lamp operating The arc tube which contains mercury when high voltage is applied to the electrodes, which causes arc to form which heats the mercury which produces a vapour of mercury,the arc now passes through the vapour.the light produced is a direct result of the discharge through the vapour Applications Used where colour rendering is not a issue for example street lighting,car parks,flood light of buildings,general outdoor commercial and industrial uses
- Low pressure sodium lamp operating principles An arc tube which is filled with neon gas-a small amount of sodium is placed in when the strike take place the sodium vaporises and gives a pinkish reddish light within few minutes the light turns yellow the light will come up to its rated light out in approximately 10 minutes Applications Used where colour rendering is not an issue like roadways, motorways and for general outdoor lighting
- High pressure sodium lamp operating principles The Arc Tube is the light producing source. Heat from the arc vaporises the liquid mercury into a gas and the mercury enters the arc stream. The arc constricts and gets brighter generating more heat. Heat from the mercury arc vaporises the sodium into a gas when this happens it produces light Applications Street lighting, indoor plants
- Tungsten halogen lamp operating principle It has a tungsten coil in a vacuumed glass and has a higher like iodine bromine added the halogen redeposits the evaporated tungsten back on the coil-this is called the halogen cycle Application Auto headlight, home interior lighting, security lamps that are activated by motion sensors Domestic and commercial lighting of small areas, suitable for dimmer circuits
- With regard to illumination, briefly explain the inverse square law? The inverse square law, The intensity of light is inversely proportional to to the square of the distance
- With regard to illumination, briefly explain the cosine law? The illumination produced on a surface by a point source is proportional to the cosine of the angle of the incidence
- What does hid stand for. High intensity discharge
- Explain what is meant by the term power factor? Power factor is the relationship between true power and apparent power. power factor is a measure of how efficiently electrical power is consumed
- How a Immersion heater works? Emersion heater heat water directly from inside the tank. A strong electric current is passed through the element which heats the water around it.
- Identify the various voltages is used for generation, transmission and distribution? The generation voltage 25000volts(25kv The three transmission voltages are 400kv 275kv 132kv The three distribution voltages are 33kV 11kv 400/230v
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- Mind Map on Principles of electrical, created by Jammy Khan on 26/03/2019.
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- Jammy Khan
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