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Salient pole rotors have large diameter and shorter axial length. Flux distribution is relatively poor than non-salient pole rotor, hence the generated emf waveform is not as good as cylindrical rotor. Salient pole rotors generally need damper windings to prevent rotor oscillations during operation.
What is meant by salient pole?
: a magnet pole that projects toward the armature of an electric machine — compare consequent pole.
What is the difference between salient and non-salient?
The third difference between salient pole and cylindrical pole is that the cylindrical pole (non-salient) design is much more durable and has a much lower winding loss than a salient pole unit. Next, its diameter is smaller but the axial length is longer. Also, both winding and noise are less than salient polar rotors.
Where is salient pole used?
Where is the salient pole rotor used? About the salient pole rotor speed, it is mainly used for low- and medium-speed output because of its mechanical instability at higher speeds. It is used in hydropower plants. It is also used in water turbine-powered in low-speed generators.
What is meant by armature?
In electrical engineering, an armature is the component of an electric machine which carries alternating current. When the machine or motor is used as a motor, this EMF opposes the armature current, and the armature converts electrical power to mechanical power in the form of torque, and transfers it via the shaft.
What does 4 pole isolator mean?
What is a 4 Pole Isolator? An isolator which includes 4 poles is termed as a 4-pole isolator. In this kind of electrical isolator, three poles use the isolator and remaining one pole will be neutral. This type of isolator is used to connect an electrical component with 230V and rated with a single phase.
What does non salient mean?
Adjective. nonsalient (not comparable) Not salient.
What is the definition of salient?
1 : moving by leaps or springs : jumping. 2 : jetting upward a salient fountain. 3a : projecting beyond a line, surface, or level. b : standing out conspicuously : prominent especially : of notable significance similar to … Prohibition, but there are a couple of salient differences — Tony Gibbs.
What are the advantages of salient pole type construction?
Advantages of salient-pole type construction are : They allow better ventilation. The pole faces are so shaped that the radial air gap length increases from the pole center to the pole tips so that the flux distribution in the air-gap is sinusoidal in shape which will help the machine to generate sinusoidal emf.
What is meant by two reaction theory?
Two Reaction Theory was proposed by Andre Blondel. The theory proposes to resolve the given armature MMFs into two mutually perpendicular components, with one located along the axis of the rotor of the salient pole. It is known as the direct axis or d axis component.
Which type of rotor is best for a turbo alternator?
Smooth cylindrical type rotor is generally used for high speed alternators or turbo alternators.
What is the pole in alternator?
Poles in an alternator refer to the magnetic poles created in the rotor. The simplest example would be a two pole machine using a permanent magnet that is spinning inside an external winding.
Why salient pole alternators are not suitable for high speeds?
Salient pole machines are not suitable for high speed operations, why? The salient pole rotors cannot withstand the mechanical stresses developed at high speed. The projecting poles may be damaged due to mechanical stresses. vibrations are developed.
What is a salient pole generator?
Salient pole Generators will have large diameter and short axial length. Pole shoes cover 2/3 of the pitch. Salient Poles are laminated in order to reduce eddy currents. They are used in hydraulic turbines or diesel engines. Salient pole generators will have typical speed about 100 to 375 rpm.
What is an inverted V curve?
The Inverted V Curve is a graph showing the relation of power factor as a function of field current.
What is meant by slip test?
What is meant by slip test? Slip test is used to find the ratio of xd/xq , (that is the ratio of direct axis reactance to quadrature axis reactance). this is practically done by rotating the rotor of the alternator by an external prime mover (generally a dc motor) while rotor windings of the alternator are kept open.
How does a salient pole rotor work?
Salient pole rotor Direct current (DC), from an external exciter or from a diode bridge mounted on the rotor shaft, produces a magnetic field and energizes the rotating field windings and alternating current energizes the armature windings simultaneously.
What is synchronous speed?
: a definite speed for an alternating-current machine that is dependent on the frequency of the supply circuit because the rotating member passes one pair of poles for each alternation of the alternating current.
What is meant by non salient pole?
Non-salient pole rotors are cylindrical in shape having parallel slots on it to place rotor windings. Damper windings are not needed in non-salient pole rotors. Flux distribution is sinusoidal and hence gives better emf waveform. Non-salient pole rotors are used in nuclear, gas and thermal power plants.
What is the pole in motor?
The motor drive energizes stator teeth one after the other to make the rotor turn, thanks to its magnets’ tendency to force alignment with the stator teeth. Simply defined, a pole is a north or south magnetic field of force that is generated by a permanent magnet or current passing through a coil of wire.
What is the difference between 2 pole and 4 pole?
A 4-pole motor has about 3.0 ft-lbs of torque per horsepower whereas a 2 pole motor has 1.5 ft-lbs of torque. At 60Hz, a 4-pole motor is about 1800 rpm where a 2-pole motor is 3600 rpm. Thus, the 4-pole motor provides higher-efficiency, higher torque per unit of volume and weight.
What is meant by synchronising current?
No current circulates between the two and no power is transferred from one to the other. Under this condition emf of alternator 1, i.e. E1 is equal to and in phase opposition to emf of alternator 2, i.e. E2 as shown in the Figure .
