Explain the need and steps to conduct the reduced voltage running up test on the three phase induction motor.
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Apr 16, 2020
by
anonymous

For a balanced three phase star connected load for which line voltage is 230V and per phase resistance and reactance is 6 Ohm and 8 Ohm respectively. Calculate: 1) phase voltage 2) line current 3) power factor 4) total power absorbed
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203 views
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Aug 12, 2018
by
anonymous

Write the relation between phase and line current, phase and line voltage for Star connection.
Last Answer : Line voltage is equal to root three times of phase voltage and line and phase currents are equal in star connection
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374 views
2 answers
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Aug 11, 2018
by
anonymous

What is line voltage and phase voltage? Draw balanced three phase star connected system. Show all the voltages and currents.
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125 views
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asked
Aug 11, 2018
by
anonymous

Draw the waveform of three phase AC supply voltage.
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212 views
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Aug 11, 2018
by
anonymous

A single core cable is designed to work for a single phase system with a peak voltage of 220 kV. The maximum permissible stress in the dielectric is not to exceed 20 kV/mm. For economical size, the overall core diameter of the cable is (A) 28.2 mm (B) 26.4 mm (C) 24.4 mm (D) 22.0 mm
Last Answer : A single core cable is designed to work for a single phase system with a peak voltage of 220 kV. The maximum permissible stress in the dielectric is not to exceed 20 kV/mm. For economical size, the overall core diameter of the cable is 22.0 mm
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755 views
1 answer
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Apr 28, 2018
by
anonymous

In an alternator at lagging power factor the generated voltage per phase as compared to that at unity power factor?
Last Answer : In an alternator, at lagging power factor the generated voltage per phase as compared to that at unity power factor must be more than terminal voltage.
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524 views
1 answer
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Mar 18, 2018
by
anonymous

What is the difference between line and phase voltage?
Last Answer : Line voltage is voltage between two phases R &Y (415 v) while phase voltage is the voltage between one phase and a neutral B & N (240 v).
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207 views
1 answer
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Mar 10, 2018
by
anonymous

Explain the principle of ON-OFF control and phase control of AC voltage controller with suitable circuit and waveforms.
Last Answer : The integral cycle control (on-off control) and phase angle control are the two types of AC voltage controller. The principle of ON-OFF control: The on-off control is also called an integral cycle ... control. In phase control, the switch is on for some period of each cycle.
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3.5k views
1 answer
asked
Feb 14, 2018
by
anonymous

What is the voltage in 3 phase line?
Last Answer : between 430 to 440 v
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283 views
4 answers
asked
Dec 22, 2017
by
anonymous

The instructions for starting the computer are house on a. Random access memory b. CD-Rom c. Read only memory chip d. All of above
Last Answer : c. Read only memory chip
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19 views
1 answer
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Aug 4, 2021
by
anonymous

How to Speed Read
Last Answer : How to Speed Read Got loads of books to finish for your history class tomorrow? Cramming all those information in your head and finishing all those reading materials might seem impossible, but there's ... possible. Just remember these simple tips, and you'll soon know how to speed read efficiently.
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How to Read Body Language
Last Answer : How to Read Body Language Body language is the silent language we all need to know and understand. Reading body language correctly will give us accurate clues and hints on what a person ... or another person mirroring your actions means that the person is attracted or is comfortable around you.
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1 answer

How to Read a Ruler
Last Answer : How to Read a Ruler Introduction The ruler is used for various measuring and drawing techniques. You can perform the perfect straight line, build an entertainment center or know that the newly purchased ... or 32 mm. When measuring any object, mark each side carefully to receive an accurate reading.
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1 answer

How to Read a Map
Last Answer : How to Read a Map Reading a map is not just essential in traveling, it's essential in everyday living too. Imagine having to go to an unfamiliar part of the city for a job interview and ... roads into consideration. If you enjoyed reading this article, you'll surely enjoy learning how to use GPS.
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1 answer

How to Teach a Child to Read
Last Answer : How to Teach a Child to Read Most children learn how to read when they are four or five years old, but it doesn't hurt to get them started and hooked on reading. Reading and comprehension are ... up a new world of opportunities for your child to explore in the fabulous and magical world of reading.
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7 views
1 answer
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May 12, 2021
by
anonymous
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How to Read Roman Numerals
Last Answer : How to Read Roman Numerals Roman numerals were how the ancient Romans wrote down numerical values, and a modern version of this numerical system is still used today. Whether it's on that building facade or a costume Roman period movie, here' ... D (500) + C (100) + C (100) + XL (40) + IX (9) = 749.
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10 views
1 answer
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May 10, 2021
by
anonymous

How to Read Blood Test Results ?
Last Answer : How to Read Blood Test Results When getting your blood tested, you need someone qualified to translate the blood test results for you. However, it's natural that you are interested in your ... diabetic. To lower or remove the risk entirely, doctors will usually prescribe weight loss and exercise.
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9 views
1 answer
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May 8, 2021
by
anonymous

The average time required to reach a storage location in the memory to read or retrieve the contents of memory is called as A) Turnaround time B) Latency time C) Access time D) Response time
Last Answer : The average time required to reach a storage location in the memory to read or retrieve the contents of memory is called as Access time
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239 views
1 answer
asked
Jun 18, 2018
by
anonymous

How do you read a KWH Meter?
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78 views
0 answers
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Mar 10, 2018
by
anonymous

A single phase transformer has resistance and reactance of 0.2 pu and 0.6 pu respectively. Its pu voltage regulation at 0.8 pf lagging would he
Last Answer : A single phase transformer has resistance and reactance of 0.2 pu and 0.6 pu respectively. Its pu voltage regulation at 0.8 pf lagging would he 0.52
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367 views
1 answer
asked
May 3, 2018
by
anonymous

The potential coil of a single phase dynamometer wattmeter has 4840 Ohm resistance. Voltage across the load is 220 V. With the potential coil connected on the load side, the meter indicates 100 W. Approximate percentage error due to wattmeter connection is (A) 11% (B) 9% (C) 1.1% (D) 3%
Last Answer : The potential coil of a single phase dynamometer wattmeter has 4840 Ohm resistance. Voltage across the load is 220 V. With the potential coil connected on the load side, the meter indicates 100 W. Approximate percentage error due to wattmeter connection is 11%
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319 views
1 answer
asked
Apr 25, 2018
by
anonymous

The product of apparent power and cosine of the phase angle between circuit voltage and current is?
Last Answer : In parllpar reasonans RLC circuit the current is
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647 views
2 answers
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Mar 25, 2018
by
anonymous

The phase difference between voltage and current wave through a circuit element is given as 30°. The essential condition is that?
Last Answer : The phase difference between voltage and current wave through a circuit element is given as 30°. The essential condition is that both waves must have same frequency.
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782 views
1 answer
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Mar 24, 2018
by
anonymous

The power consumed in a circuit element will be least when the phase difference between the current and voltage is?
Last Answer : The power consumed in a circuit element will be least when the phase difference between the current and voltage is 90°.
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939 views
1 answer
asked
Mar 24, 2018
by
anonymous

The underground system cannot be operated above (a) 440 V (b) 11 kV (c) 33 kV (d) 66 kV
Last Answer : (d) 66 kV
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5 views
1 answer

The voltage of the single phase supply to residential consumers is (a) 110 V (b) 210 V (c) 230 V (d) 400 V
Last Answer : (c) 230 V
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1 answer

If 1-phase voltage is 220V, why is 3-phase 440V and not 660V ?
Last Answer : Phase voltage =220v /( phase to neutral) Line voltage = 380 v ( phase to phase) Phase angle difference 120° So when two phases reach vmax +ve I.e. (+220v) + (+220v) = 440v that time due ... these event happen very fast. Hence we have 440 v only in three phase motor. √3.phase voltage= 380 v.
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372 views
4 answers
asked
Aug 19, 2019
by
anonymous

The kVA rating of Three-phase transformer with Voltage = 200V and Current = 100A will be : (A) 34.64 kVA (B) 75 kVA (C) 20 kVA (D) None of the above
Last Answer : The kVA rating of Three-phase transformer with Voltage = 200V and Current = 100A will be : 34.64 kVA
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199 views
1 answer
asked
May 8, 2018
by
anonymous

The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque (1) Decreases (2) Increases (3) Remains constant (4) None of the above
Last Answer : The speed of a three-phase induction motor is controlled by variable voltage variable frequency control (i.e. keeping V/f constant). As the frequency is reduced, the slip at maximum torque Increases
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227 views
1 answer
asked
May 1, 2018
by
anonymous
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A 3-phase voltage source inverter operates in 180° conduction mode with a star connected resistive load. If input dc voltage is 100 V, then the peak to peak output line voltage is :
Last Answer : A 3-phase voltage source inverter operates in 180° conduction mode with a star connected resistive load. If input dc voltage is 100 V, then the peak to peak output line voltage is : 200 V
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205 views
1 answer
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Apr 30, 2018
by
anonymous

At a particular instant, the R-phase voltage of a balanced 3-phase system is + 30 V, and the Y-phase voltage is – 90 V. The voltage of B-phase at that instant is (A) + 120 V (B) – 120 V (C) – 60 V (D) + 60 V
Last Answer : At a particular instant, the R-phase voltage of a balanced 3-phase system is + 30 V, and the Y-phase voltage is – 90 V. The voltage of B-phase at that instant is + 60 V
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108 views
1 answer
asked
Apr 25, 2018
by
anonymous

Is it possible for a soil to consist only of one phase?
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What is the operation of three phase induction motor
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SINGLE PHASE INDUCTION MOTORS MCQ
Last Answer : 101. After the starting winding of a single phase induction motor is disconnected from supply, it continues to run only on (a) running winding (b) rotor winding (c) field winding (d) compensating winding Ans: a ... motor is usually reduced by using (a) gearing (b) belts (c) brakes (d) chains Ans: a
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3 answers
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THREE PHASE INDUCTION MOTORS MCQ
Last Answer : 101. Insertion of resistance in the stator of an induction motor (a) increases the load torque (b) decreases the starting torque (c) increases the starting torque (d) none of the above Ans: b
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320 views
3 answers

How to Build a Static 3 Phase Converter
Last Answer : How to Build a Static 3 Phase Converter Static 3 phase converters enable offices and residents to conserve energy efficiently. In fact, electricity is available in 3 power phases, which enables ... converter and the necessary appliances that are needed in building the main and the remote appliances.
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6 views
1 answer
asked
May 12, 2021
by
anonymous

Draw single phase full wave mid-point converter for inductive load. Draw input and output waveforms for it.
Last Answer : Circuit Diagram: Waveforms:
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531 views
1 answer
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May 21, 2020
by
anonymous

State classification of Phase controlled rectifiers.
Last Answer : Classification of phase controlled rectifiers:
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105 views
1 answer
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May 21, 2020
by
anonymous

Single phase transformer
Last Answer : Single phase Transformer Transformer
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260 views
1 answer
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May 16, 2020
by
anonymous

Explain MCB and ELCB with connection diagram supplying single phase load.
Last Answer : OR OR Explanation: * MCB provides short circuit protection. * MCB provides overload protection * ELCB provides earth fault protection. * MCB is in series with ... occurs, the ELCB cuts off the power within the time of 0.1 sec. automatically to protect the personnel.
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581 views
1 answer
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May 7, 2020
by
anonymous

List different starting methods of three phase synchronous motor. Explain any one of them.
Last Answer : Different Starting Methods of Three Phase Synchronous Motor: As synchronous motor is not self starting, different methods of starting are as follows: 1) By using an Induction (Pony) motor 2) ... . The rotor gets pulled into synchronism and starts running at constant speed as a synchronous motor.
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156 views
1 answer
asked
May 7, 2020
by
anonymous

State suitable single phase motor for following applications: (i) Table fan (ii) Mixers and Grinders
Last Answer : Application Suitable Single Phase Motor Table Fan 1) Capacitor split phase motor 2) Capacitor start capacitor run motor Mixers and Grinders 1) Universal motor 2) A.C. Series motor
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96 views
1 answer
asked
May 7, 2020
by
anonymous

Draw & explain operation of phase detector.
Last Answer : In phase detector, the op-Amp basically acts as a zero crossing detector. If a sine wave is applied at the i/p, we get square wave at the op-Amp o/p (at point ... to two channel of the CRO. The time duration between the pulses corresponding to voltages represent the phase between them.
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127 views
1 answer
asked
May 2, 2020
by
anonymous

Explain the concept of lagging and leading phase angle by waveform.
Last Answer : i) Leading phase angle : When two ac quantities of same frequency do not attain their respective zero or peak values simultaneously, then the quantities are said to be out-of-phase quantities. The ... Similarly, in the second diagram, the voltage is said to be lagging the current by Φ.
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374 views
1 answer
asked
Apr 27, 2020
by
anonymous

Explain the procedure to perform Short Circuit test on single phase transformer with circuit diagram.
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111 views
0 answers
asked
Apr 27, 2020
by
anonymous

Explain with neat circuit diagrams the procedures to perform no load and blocked rotor tests on three phase induction motor.
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127 views
0 answers
asked
Apr 16, 2020
by
anonymous

Why is a capacitor used in a single phase motor and not in three phase motor ?
Last Answer : In 1-phase induction motor capacitor work is generate the auxiliary winding current than excite the main winding to rotor starts rotate. After rotor start rotating about 75% of their speed than auxiliary ... emf to start the motor.so,in 3-phase induction motor is self start induction motor.
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259 views
6 answers
asked
Sep 2, 2019
by
anonymous

Define Amplitude and Phase of Sinusoidal quantity.
Last Answer : Amplitudes are expressed either as instantaneous values or mostly as peak values. Amplitude is the fluctuation or displacement of a wave from its mean value. Phase is the position of a ... . Phase an expression of relative displacement between or among waves having the same frequency .
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165 views
1 answer
asked
Aug 21, 2019
by
anonymous

working principle of single phase motor
Last Answer : The Stator of single phase induction motor houses two windings 1. Main (Running) winding 2. Auxiliary (Starting ) winding Rotor of single phase induction motor is ... with starting winding or a capacitor may be permanently connected in series with Auxiliary (Starting ) winding.
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167 views
1 answer
asked
Aug 21, 2019
by
anonymous
