The term power factor comes into picture in AC circuits only. Mathematically it is cosine of the phase difference between source voltage...
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what is skin effect and how its occurs ?
what is Skin Effect ? The phenomena arising due to unequal distribution of current over the entire cross section of the conductor bein...
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what is corona effect and hoe it ocure and how it reduce ?
Electric transmission lines can generate a small amount of sound energy as a result of corona. Corona is a phenomenon associated ...
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What is ferrantic effect?
Output voltage is greater than the input voltage or receiving end voltage is greater than the sending end voltage. Skin effect is a...
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What is the power factor of an alternator at no load?
At no load Synchronous Impedance of the alternator is responsible for creating angle difference. So it should be zero lagging like indu...
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Mention the methods for starting an induction motor?
The different methods of starting an induction motor: a)DOL:direct online starter b)Star delta starter c)Auto transformer starter d)Resi...
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What is reverse power relay?
Reverse Power flow relay are used in generating stations's protection. A generating stations is supposed to fed power to the grid a...
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What is the difference between isolators and electrical circuit breakers? What is bus-bar?
Isolators are mainly for switching purpose under normal conditions but they cannot operate in fault conditions .Actually they used for i...
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What will happen if DC supply is given on the primary of a transformer?
Mainly transformer has high inductance and low resistance.In case of DC supply there is no inductance ,only resistance will act in t...
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State the methods of improving power factor?
Methods of improving power factor: • By connecting static capacitors in parallel with the load operating at lagging power factor. • A sy...
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Name the types of motors used in vacuum cleaners, phonographic appliances, vending machines, refrigerators, rolling mills, lathes, power factor improvement and cranes.
Following motors are used: - • Vacuum cleaners- Universal motor. • Phonographic appliances – Hysteresis motor. • Vending machines – Shade...
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What are the different methods for the starting of a synchronous motor.
Starting methods: Synchronous motor can be started by the following two methods: • By means of an auxiliary motor: The rotor of a synchro...
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Explain advantages of storage batteries
Few advantages of storage batteries are mentioned below: • Most efficient form of storing energy portably. • Stored energy is available i...
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Explain the application of storage batteries.
Storage batteries are used for various purposes, some of the applications are mentioned below: • For the operation of protective devi...
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What is slip in an induction motor?
Slip can be defined as the difference between the flux speed (Ns) and the rotor speed (N). Speed of the rotor of an induction motor is a...
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Why back emf used for a dc motor? highlight its significance.
The induced emf developed when the rotating conductors of the armature between the poles of magnet, in a DC motor, cut the magnetic flux...
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What are the various kind of cables used for transmission?
Cables, which are used for transmitting power, can be categorized in three forms: • Low-tension cables, which can transmit voltage upto 1...
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Why AC systems are preferred over DC systems?
Due to following reasons, AC systems are preferred over DC systems: a. It is easy to maintain and change the voltage of AC electricity fo...
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Why star delta starter is preferred with induction motor?
Star delta starter is preferred with induction motor due to following reasons: • Starting current is reduced 3-4 times of the direct curr...
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Types of Electrical Insulator | Overhead Insulator
There are mainly three types of insulator used as overhead insulator likewise Pin Insulator Suspension Insulator Str...
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