Table of Contents
Salient Pole Alternator: Poles are projecting out from the surface. The air gap is non-uniform. Diameter is high and the axial length is small. This is preferred for low-speed alternators ranging from 125 r.p.m to 500 RPM. Separate damper winding is provided.
What is salient pole type alternator?
The term salient means protruding or projecting. The salient pole type of rotor is generally used for slow speed machines having large diameters and relatively small axial lengths. The poles, in this case, are made of thick laminated steel sections riveted together and attached to a rotor with the help of joint.
What is the salient pole?
: a magnet pole that projects toward the armature of an electric machine — compare consequent pole.
What is difference between salient pole and non-salient pole?
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.
What is the advantage of salient pole in an alternator?
reduced noise. reduced windage loss. adoptability to low and medium speed operation.
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 maximum speed of 50 Hz alternator?
Answer is “3000 rpm”.
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 EMF equation of alternator?
V = 4.44 Kf KC KD f ΦT Volts. Where: V = Actual generated Voltage per phase.
Why synchronous motors are not self starting?
Above a certain size, synchronous motors are not self-starting motors. This property is due to the inertia of the rotor; it cannot instantly follow the rotation of the magnetic field of the stator. Once the rotor nears the synchronous speed, the field winding is excited, and the motor pulls into synchronization.
Is rotor and alternator same?
The rotor is a moving component of an electromagnetic system in the electric motor, electric generator, or alternator. Its rotation is due to the interaction between the windings and magnetic fields which produces a torque around the rotor’s axis.
What is meant by synchronous machine?
: a dynamoelectric machine (such as a generator or motor) that has a constant magnetic field and an armature which receives or delivers alternating current in synchronism with the motion of the machine and at a frequency equal to the product of the number of pairs of poles and the speed of the machine in revolutions.
What is Alternator hunting?
Hunting occurs when the rotor position is ahead or behind the normal position. In mainly occurs in alternators driven by reciprocating engines, where the torque of rotation varies periodically; due to action of one power stroke per cycle.
Which prime mover is used for high speed alternator?
The prime movers used for salient pole alternators are water wheels like Kaplan turbine, Francis turbine, Pelton wheel etc., and diesel or petrol engines. The prime movers used for non-salient pole alternators are steam turbines and gas turbines. 7. Salient pole machines are not suitable for high speed operations, why?.
How many Poles does a turbo alternator have?
Explanation: The turbo-alternators are made up of 2 poles. The speed with which the turbo alternators operate are 3000 rpm.
What is the other name of alternator?
Noun. Engine converting energy. generator. dynamo.
What do you mean by 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.
How do you calculate synchronous speed?
The synchronous speed of an AC motor is determined by the frequency of the source and the number of poles. The RPM is calculated by multiplying the frequency times 60 and dividing by the number of pairs of poles. This was explained in Chapter 6. Some motors are designed to operate at synchronous speed.
Which is better 50Hz or 60Hz?
The primary difference between 50 Hz (Hertz) and 60 Hz (Hertz) is, well, 60Hz is 20% higher in frequency. Lower the frequency, speed of induction motor and generator will be lower. For example with 50 Hz, generator will be running at 3000 rpm against 3600 rpm with 60 Hz.
Can you convert 50Hz to 60Hz?
50hz to 60hz Converters These 50Hz to 60Hz frequency converters are designed to supply 3 phase alternating current (AC) critical loads with high stability 50Hz or 60Hz frequency from a 50Hz or 60Hz input power source. Equally, the system can be used when 60Hz equipment is required to operate from a 50Hz power supply.
What is the maximum speed of alternator?
Typically, alternators have their full output rated at 6000 RPM but can continue to spin up to 12,000 RPM or more without any additional increase in output. The speed of an alternator is different for different type of car. The speed of an alternator depends on the speed of the engine.
Which kind of rotor is most suitable for alternators which are designed to run at high speed?
177. What kind of rotor is most suitable for turbo-alternators which are designed to run at high speed? 178. The power developed in the alternator having salient type rotor is less than of having non-salient pole.
Which kind of motor is most suitable for turbo alternator which are designed to run at high speed?
Non-salient pole type or cylindrical type rotors are used in high-speed alternators or turbo-alternators having speed between 1500 rpm to 3000 rpm.
How is turbo alternator driven by?
Explanation: The turbo alternators are one category among the synchronous machines. They are driven by the steam turbines. The speed of the turbo-alternators is 1000 MW.
What is the formula for back EMF?
The back emf is calculated based on the difference between the supplied voltage and the loss from the current through the resistance. The power from each device is calculated from one of the power formulas based on the given information. The back emf is ϵi=ϵS−I(Rf+REa)=120V−(10A)(2.0Ω)=100V.
How do you calculate the emf?
The emf is equal to the work done on the charge per unit charge (ϵ=dWdq) when there is no current flowing. Since the unit for work is the joule and the unit for charge is the coulomb, the unit for emf is the volt (1V=1J/C).
What is the formula of induced emf?
The induced emf is ε = – d/dt (BA cos θ). The magnitude of the magnetic field can change with time. The area enclosed by the loop can change with time. The angle between the magnetic field and the normal to the loop can change with time.
