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The 'field'winding is in the rotor which rotates at the synchronous speed generating AC powerat the right frequency in the stator. That requires DC in the rotor. It is convenient because the DC is supplied to the rotor through slip rings, smooth polished rings which allow the carbon brushes to last a long time.
What else can I help you with?
Why the field windings are placed in rotor of alternator?
In an alternator, field windings are placed on the rotor to create a rotating magnetic field necessary for inducing electrical current in the stator windings. This configuration allows for a more compact design and enables the use of higher magnetic flux densities, improving the alternator's efficiency. By placing the field windings on the rotor, the alternator can generate a strong magnetic field while keeping the stator stationary, which simplifies the design and minimizes wear on the components. Additionally, this arrangement allows for easier cooling of the rotor and better control of the magnetic field strength.
What is over excitation of field windings?
Over-excitation of field windings refers to a condition in synchronous machines, such as generators, where the field current exceeds the rated value, leading to an excessive magnetic field. This can result in increased voltage output and potential overheating of the machine. Prolonged over-excitation can damage the windings and other components due to overheating and insulation breakdown. It is critical to monitor and control the excitation levels to maintain safe and efficient operation.
Does a induction motor need excitation?
The induction motor is the special kind of motor which runs below and above the synchronous speed. which the synchronous motor runs nearly equal the synchronous speed. The operation of synchronous motor runs with dc field excited hence separate dc field current is given to the field circuit. where as the induction motor the field and main field is drawn from the same supply hence no excitation is required. But due to this separate starting mechanism has to be required in case of the single phase induction motor.
Can you use the separately excited shunt generator machine as self excited generator?
You have a seperately excited generator and then you have a shunt generator which has the field winding in parallel with the armature terminals. In DC machines a separately excited generator could be run as a shunt generator provided the field winding is designed to work on the generated voltage. A separately excited alternator needs a DC supply for the field winding. In car alternators that is taken from the main winding via a rectifier and a voltage regulator.
What is a exciter generator?
its creates the magnetic field trough the electricity,which we called exciter for it.we send some electric shocks to the field coils,then it will magnetized the stater of the generator. When Diesel or petrol engine rotates the rotter of the generator, EXCITED stater act as a magnet. Depend on alternator`s design,rotter or stater one always EXITED to be a magnet. When engine turns the Alternator against the magnetic field,electricity is produced.
How is automotive alternator initially excited?
An automotive alternator is initially excited through a process called residual magnetism. When the engine starts, the alternator's rotor, which contains permanent magnets or is electromagnetically induced, generates a small magnetic field due to residual magnetism. This initial magnetic field induces a small alternating current (AC) in the stator windings. Once the engine runs, the voltage regulator takes over, supplying a larger current to the rotor's field windings to increase output.
Why the field windings are placed in rotor of alternator?
In an alternator, field windings are placed on the rotor to create a rotating magnetic field necessary for inducing electrical current in the stator windings. This configuration allows for a more compact design and enables the use of higher magnetic flux densities, improving the alternator's efficiency. By placing the field windings on the rotor, the alternator can generate a strong magnetic field while keeping the stator stationary, which simplifies the design and minimizes wear on the components. Additionally, this arrangement allows for easier cooling of the rotor and better control of the magnetic field strength.
How Synchronous motor work with principal?
A synchronous motor comprises of a stator windings and a rotor with a squirrel cage and inside that is windings(coils). At starting, this motor is an induction motor running with slip. After the rotor has reached a certain speed, a DC current is applied to the windings inside the squirrel cage. A fixed field is induced in these windings. This field locks in with the synchronous rotating magnetic flux of the stator windings. The rotating stator windings then pull the rotor along. The amount of excitation current can be used to control the power factor of the motor, making this a popular type of motor for high power use with a constant mechanical load.
In an alternator what is the initial excitation current from the battery is supplied to?
In an alternator, the initial excitation current from the battery is supplied to the rotor windings. This current establishes a magnetic field necessary for the alternator to generate electricity. Once the rotor starts spinning, the magnetic field induces an alternating current (AC) in the stator windings, allowing the alternator to produce electrical power. The initial excitation is crucial to kick-start the generation process.
Why the synchronous machine rotate at synchronous speed?
The spatial distribution of the windings in the armature is designed in a way such that it produce a rotating field when a three phase source is applied to its terminals. The field windings have a DC field applied to it and it is rotated mechanically by a prime mover. If the prime mover tried to rotate the synchronous machine at speed higher than its synchronous value then the power output of the generator will increase and this causes the speed to "lock" again to the synchronous one. If the prime mover applied less torque then the machine will slow down but the power output will decrease DUE TO DECEASE in the applied torque and this cause the machine to "lock" again to synchronous speed of the grid. The same principle can be applied to synchronous motors except that torque is negative (i.e. the prime mover is applying negative torque)
Where is the magnetic field created alternator?
The magnetic field in an alternator is created by the rotor, which is an electromagnet that produces a rotating magnetic field as it spins. This magnetic field induces an alternating current in the stator windings through electromagnetic induction, which is then converted to usable electrical power.
Working principle of synchronus motor?
A synchronous motor is a three phase motor, which uses a magnetic field created by permanent magnets or a DC electromagnet on the rotor (usually). The stator windings have 3 phase voltages applied, and coupled with the DC field, create a rotating magnetic field that drives the motor at synchronous speed.
What is over excitation of field windings?
Over-excitation of field windings refers to a condition in synchronous machines, such as generators, where the field current exceeds the rated value, leading to an excessive magnetic field. This can result in increased voltage output and potential overheating of the machine. Prolonged over-excitation can damage the windings and other components due to overheating and insulation breakdown. It is critical to monitor and control the excitation levels to maintain safe and efficient operation.
Does a induction motor need excitation?
The induction motor is the special kind of motor which runs below and above the synchronous speed. which the synchronous motor runs nearly equal the synchronous speed. The operation of synchronous motor runs with dc field excited hence separate dc field current is given to the field circuit. where as the induction motor the field and main field is drawn from the same supply hence no excitation is required. But due to this separate starting mechanism has to be required in case of the single phase induction motor.
How a brush type 3 phase alternator works?
A pair of slip rings on the rotor carries current from the stationary brushes to the rotor windings in order to establish a magnetic field. As the alternator rotates, the magnetic field sweeps across the stator windings inducing an electric current in these windings. This current is an alternating current which is rectified via diodes and passed out of the alternator by means of the battery lead and (usually) the grounded alternator case. The battery voltage is sensed and used to vary the amount of current fed to the rotor in order to adjust the amount of current generated.
What is difference between synchronous motor and synchronous condenser?
A synchronous motor is designed to convert electrical energy into mechanical energy to produce rotation, while a synchronous condenser is designed to only regulate voltage and improve power factor on the electrical grid without mechanical output. Both devices are synchronous machines that operate based on the principles of synchronous operation and require a magnetic field to be established.
Working principle of 3 phase alternator?
A three-phase alternator has three sets of windings that produce three currents. The three currents make up the three phases. Together these produce the total AC output of the stator. An alternator is made up of a stator and a magnet rotor which is also known as the flywheel.
