Automatic voltage regulator for generator

The AVR ( automatic voltage regulator ) is suitable for supplying power to the fields of either brushless or commutator type exciters and will maintain the A.C generator voltage within plus and minus 1% of the preset value with paralleling.

When the load varies between no load and rated load and with a frequency changes more than plus minus 4%.Upon application or rejection of rated load,the generator voltage recovers to plus and minus 1% within 0.3 second on most AVR exciter in A.C generator combination. read more

Low speed protection for A.C generator

For a given excitation,if speed of an A.C. generator is reduced then the output voltage would reduce also.In practice,this reduction in output voltage is sensed by the AVR ( Automatic voltage regulator ) which increases the excitation current to compensate.

However,the field forcing capabilities of the AVR which are necessary to maintain output voltage during rapid load changes,will permit an “over-excitation” condition to exist.

As the regulator is not speed ( or frequency) sensitive,field forcing would occur damage field windings and rotating diode.In order to safeguard the machine against this condition,particularly where low speed duty or idling is anticipated a LSP ( low speed protection ) unit is available to sense prolonged over-excitation and automatically insert current limiting resistance in the field circuit. read more

Generators in parallel

When generators are operated in parallel condition,it necessary to be arrange for both real power ( kW ) and reactive load ( kVar ) sharing in proportion to their standard rating.Real load output from generator determined by torque applied to the shaft and this can only be controlled by controlling the prime mover driving the generator.

Reactive load is a function of generator excitation.Under parallel operation,adjustment to field excitation does not affect to output voltage.In general,an under-excited machine will generate at a more lagging power factor current.

The three phase sensing regulator operates in similar manner except that the voltage across the reactor carrying a current proportion to one phase current is added to the voltage of that phase. read more

Generator Synchronization

Most of the electricity consumed today is produced by three phase synchronous  generator.Since a huge amount of electricity is consumed every day,AC power networks are generally made up of a large number of synchronous generator all operating in the same frequency.

When the power demand increase,additional generator are connected to the AC power network.Before connecting a three phase synchronous generator to an AC power network,the following conditions are to be observed :-

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Generator Rating

Usually the generator is designed to capable to delivery the power supply required due to time basic ( hour ) to ensure reliable operation and prevent serious breakdown.

Typically a given set can deliver more power for fewer hours per year, or less power continuously. That is a standby set is only expected to give its peak output for a few hours per year, whereas a continuously running set, would be expected to give a somewhat lower output, but literally continuously, and both to have reasonable maintenance and reliability. read more

Diesel Generator

This equipment is very common use in power generator industry or backup power supply system.We can found it at many places likes hotel,construction site,factory,hospital,engineering sites,oil and gas industry,on ship and many more.

It is the combination of mechanical power source with electrical generator or in others name it call an “alternator” to generated the electricity.For the mechanical power source,it use the engine powered by fuel.Normally it use diesel due to price and capability of performance.

Diesel generator is completely design with control panel,base,canopy,diesel tank,engine compartment,distribution box,circuit breaker and starting system in one compact package unit. read more