What is cogeneration

Cogeneration refers to the generation of both electricity and heat from a power plant.  This improves the overall efficiency of the power plant.  The efficiency of such plants can reach 85%.

In an normal power plant driven by a boiler and a turbine, all the thermal heat is not converted into electricity.  This heat is recovered in a cogeneration plant.  This heat can be used for industrial process and also for domestic heating in places which are cold.  

In plants driven by steam turbines, the hot steam is used to drive the turbine.  The outlet steam of the turbine is then used to heating homes.  


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What is a Captive Power Plant ?

A captive power plant is a power plant owned by an factory for its own power consumption.  That is, all the power generated in the captive power plant is consumed by the factory itself.

Many industries such as textile units, cement factory and petrochemical industries require cheap and reliable power.  The utility may not always meet their needs.  Hence, they set up their own power plants.  These plants do not supply power to the grid.  

These plants are mostly less than 50 MW.


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The Alternator in a Car

The Alternator in a car generates power for all the electrical equipment in the car.  The Alternator is driven 
by the engine by means of a belt known as the serpentine belt.  The belt drives the shaft of the alternator.  

The rotor of the Alternator contains the field windings.  The field windings are excited by a Voltage regulator. 

The exciting supply to the field windings is through slip rings.  This supply is taken from the batteries.  The 
power is generated on the stator of the alternator which makes evacuation easier.  

The output of the Alternator is AC.  This AC supply is converted into DC by means of diodes.  The DC supply is used to charge the battery and to supply power to all the electrical fitments in the car. 


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What is an Anti Fuse ? Where is it used

An Anti fuse is a device which fuses when there is a high voltage across it.  Just as a fuse opens the circuit in the case of an abnormality, the antifuse closes the circuit in the event of an abnormality.

An example of an antifuse can be a serial light connected to the domestic supply voltage.  The individual bulbs are not rated for the domestic voltage.  However, as they are connected in series, they are able to withstand and function in the domestic supply voltage.

A series of 48 lamps of a rating of 2.5 volts can withstand 120 volts.  A series of 96 lamps can withstand 240 volts.

When one lamp in the series fails, there is a risk of the other lamps not getting the supply as the circuit is open circuited.

This is avoided by having an antifuse below the filament which fuses when the bulb filament fails.  This happens as the system voltage is applied across the single bulb.

Once the antifuse operates and closes the open circuit, the current flows as usual to the remaining lamps.

In Electronics, antifuses function by modifies the circuit in microchips depending on the logic to be programmed.  An antifuse is typically an insulating layer sandwiched between two conducting layers.  When the chip is to be programmed, a voltage is impressed across the layer which fuses.

Posted by: Electrotechnik