Table of Contents
In salient pole type of rotor consist of large number of projected poles (salient poles) mounted on a magnetic wheel. Salient pole rotors have large diameter and shorter axial length. They are generally used in lower speed electrical machines, say 100 RPM to 1500 RPM.
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 does salient pole mean?
: a magnet pole that projects toward the armature of an electric machine — compare consequent pole.
What is the difference between salient and non salient pole rotor?
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 maximum speed of 50 Hz alternator?
Answer is “3000 rpm”.
What are the type of losses inside the alternator?
There are two: Friction and windage losses – These are losses due to the bearings, fans or blowers and the rotor itself. Core losses – These are losses caused by hysteresis (a magnetic ‘friction’ caused by the alternating magnetic flux flow) and eddy currents (induced electrical currents).
What does non salient mean?
Adjective. nonsalient (not comparable) Not salient.
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.
Which rotor is used in thermal power plant?
Which of the following rotor is used in thermal power plants? Cylindrical rotor is also called as round rotor or smooth rotor, there is no projection, there a closed portion contain field winding which is distributed and unslotted portion also acts as poles .
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.
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.
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.
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?.
What happens as the speed of an alternator increases?
As the load on an alternator is increased, the speed of the prime mover will drop. This is an unacceptable situation, because the speed controls the frequency of the generated voltage. To maintain a constant frequency, the prime mover must be governed to run at constant speed over the entire range of expected loads.
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.
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.
What are the two types of turbo alternators?
On account of the high rotating speeds, two types of turbo- alternator rotor designs, radial-slot type and parallel-slot type are used.
What are the 3 types electrical losses in alternator?
Power losses occur in the alternator due to a number of different mechanisms. These can be lumped into 3 categories: electrical, magnetic, and mechanical.
What is the formula for voltage regulation of an alternator?
the voltage regulation of an alternator is defined as the change in its terminal voltage when full load is removed, keeping field excitation and speed constant, divided by the rated terminal voltage. The value of the regulation not only depends on the load current but also on the power factor of the load.
What is the efficiency of an alternator?
The standard alternators generally have a maximum efficiency rating somewhere in the 55–60% range and the high-efficiency models are generally in the 68–75% range. These efficiency gains are mostly due to using conductors that allow greater fill of the windings in the alternator.
Can a person be salient?
Salience Definition The term salient refers to anything (person, behavior, trait, etc.) that is prominent, conspicuous, or otherwise noticeable compared with its surroundings. Salience is usually produced by novelty or unexpectedness, but can also be brought about by shifting one’s attention to that feature.
What is a salient example?
The definition of salient is something that is very noticeable, jumps or is prominent. An example of salient is a large dark mole on someone’s forehead. An example of salient is a key point in a proposal. The bell tower is the most salient feature on campus.
What is the meaning of salient features?
What Are “Salient Features”? Dr. Roman-Lantzy defines salient features as, “the defining elements that distinguish one target from another.” (Roman-Lantzy, p. “They are,” she continues, “the key pieces of distinct information that facilitate recognition of an image, object, environment, or person” (Roman-Lantzy, 2018).
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.
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.
What is the highest possible speed of turbo alternator?
What is the highest possible speed of turbo alternators? Steam turbines have good efficiency at higher speeds only. Therefore maximum speed of turbo alternators used in those power plants are 3000 rpm with two poles and next possible speed is 1500 rpm with 4 poles.
