What is an exciter?
An exciter is a type of electrical equipment that generates either alternating current (AC) (or) direct current (DC).
It operates by inducing an electrical current in a series of windings using a magnetic field.
The exciter is usually a tiny equipment that supplies field current to a bigger generator or motor.
Types of an Exciter
Exciter are 2 types
1). AC Exciter
2). DC Exciter
1). AC Exciter
The windings of an AC exciter are placed in such a way that the magnetic field generated by the exciter spins.
This produces a spinning magnetic field, which is utilised to generate an alternating current voltage in the generator or motor’s stator windings.
The frequency of the exciter’s AC output is normally varied by modifying the exciter’s speed or increasing the number of poles in an exciter.
2). DC Exciter
A voltage regulator generally controls the output voltage of a DC exciter.
The voltage regulator measures the exciter’s output voltage and regulates the exciter’s field current to maintain the constant voltage.
The DC exciter’s output voltage is often used to power the field winding of a larger generator (or) motor.
Construction of an Exciter
The construction of an exciter varies depending on its type and use, however can overview of an AC exciter.
A conventional AC exciter consists of a rotor & a stator, which are comparable to the rotor & stator of a generator.
The rotor is attached to a shaft that connects to the engine (or) turbine that powers the generator. The rotor is made up of a series of field windings installed on a laminated steel core.
The field windings are made of insulated copper wire & are intended to generate a strong magnetic field when an electrical current is delivered through them.
The stator is a fixed collection of windings that surrounds the rotor. The stator is made up of two (or) more windings that are 90 degrees apart.
When electrical power is applied to the exciter, these windings are coupled in series (or) parallel to form a revolving magnetic field.
The exciter’s output voltage is normally collected from the stator windings & controlled by a voltage regulator.
The voltage regulator monitors the exciter’s output voltage and regulates the exciter’s field current to maintain a constant voltage.
This keeps the voltage provided to the primary generator consistent.
The design of an AC exciter varies according to its use and size.
For optimal functioning and extended life, certain exciters may have extra components such as a cooling system (or) bearing.
Working of an exciter
The operation of an exciter is determined by its type, since various exciters are employed for different purposes.
In this can overview a simple AC exciter, which is often used in generators, works.
When the exciter is powered up, the rotor spins, generating a magnetic field that revolves around the stator.
This spinning magnetic field creates an alternating current voltage in the stator windings, which supplies the field current to main generator.
The frequency of the exciter’s AC output voltage is commonly varied by modifying the exciter’s speed or changing the number of poles in an exciter.
A voltage regulator normally controls the exciter’s output voltage.
The voltage regulator measures the exciter’s output voltage and regulates the exciter’s field current to maintain a constant voltage. This keeps the voltage provided to the primary generator consistent.
The exciter is a critical component of a generator because it generates the initial magnetic field needed for the generator to create electrical power. The generator cannot create any electrical power without an exciter.
Applications of an Exciter
Exciters are often used to adjust the output voltage of generators and motors in power plants & other industrial applications.
They’re also found in various electrical test equipment, such as AC & DC power sources.