What is damper winding?
: a short-circuited squirrel-cage winding placed in the pole faces and around the pole shoes of synchronous machines, the currents induced in the winding by the periodic variations in synchronous speed having the effect of a damper. — called also amortisseur.
What is synchronous motor?
A synchronous motor is one in which the rotor normally rotates at the same speed as the revolving field in the machine. The stator is similar to that of an induction machine consisting of a cylindrical iron frame with windings, usually three-phase, located in slots around the inner periphery.
What is the role of damper winding in synchronous generator?
The main purpose of using Damper winding in synchronous Machine is to provide starting torque and eliminate damping or hunting. The damper winding is used in Synchronous Motor to provide starting torque and the damper winding is used in the synchronous alternator to eliminate damping or hunting.
What is normal excitation?
Synchronous motor excitation refers to the DC supply given to rotor which is used to produce the required magnetic flux. The field current, which causes this unity power factor is called normal excitation or normal field current.
What is the role of damper winding?
Damper windings helps the synchronous motor to start on its own (self starting machine) by providing starting torque. By providing damper windings in the rotor of synchronous motor “Hunting of machine”can be suppressed.
What is the function of damping winding?
The function of the damper winding in the synchronous generator is to suppress the negative sequence field and to dampen oscillation whereas it is used to provide starting torque and reduce effect of hunting to some extent in the synchronous motor.
Why do we use synchronous motors?
In higher power industrial sizes, the synchronous motor provides two important functions. First, it is a highly efficient means of converting AC energy to work. Second, it can operate at leading or unity power factor and thereby provide power-factor correction.
What are the main parts of synchronous motor?
A synchronous motor is generally made up of two parts, a stator the stationary part of the machine that carries the armature winding in which the voltage is generated, and a rotor the rotating part of the machine that produces the main field flux.
What is excitation EMF?
The process of generating a magnetic field by means of an electric current is called excitation. Field coils yield the most flexible form of magnetic flux regulation and de-regulation, but at the expense of a flow of electric current.
Why is excitation needed?
The excitation system is responsible for supplying the field current to the main rotor. The requirements of an excitation system include reliability under all conditions of service, a simplicity of control, ease of maintenance, stability and fast transient response.
What is the basic principle of alternators?
All the alternators work on the principle of electromagnetic induction. According to this law, for producing the electricity we need a conductor, magnetic field and mechanical energy. Every machine that rotates and reproduces Alternating Current.
How synchronous motor works as a power factor correction?
The power factor of a synchronous motor is changed with a change in the excitation. When the excitation of the motor is increased, the power factor changes from lagging to unity and then to a leading power factor.
How are amortisseur windings used in traction generators?
• Also called “Amortisseur windings.” • Copper bars through the pole faces and shorted together by the end plates. • Standard for all but traction generators, solid rotors. • Has a very short time constant (effect expressed in datasheets as X”d). – Helps with parallel operation – Helps with load-induced harmonics (non-linear loads).
Can a amortisseur winding start a synchronous motor?
The Amortisseur windings can also be used to start the synchronous motors. The Synchronous motor is not self-starting. Hence, motor starts initially as an induction motor through the action of the amortisseur windings. When the sufficient speed has been attained, the excitation to the rotor of the synchronous machine is switched on.
What are amortisseur windings in a squirrel cage motor?
Amortisseur windings are bars which are found in the rotor of synchronous motors. These bars are short circuited similar to the rotor windings in a squirrel cage motor. The function of these windings is to dampen the torsional oscillations in the rotor that may occur as a result of load fluctuations. They are also known as damper windings.
What does damper winding do in a synchronous motor?
It damps out the oscillations of rotor so that the rotor takes its new position quickly. In case of synchronous motor, damper winding performs an additional function. It acts as a squirrel cage winding and makes the synchronous motor self starting. The motor starts as an induction motor and approaches near synchronous speed.