An additional condition for parallel operation of three-phase transformers over single-phase transformers is that
Last Answer : An additional condition for parallel operation of three-phase transformers over single-phase transformers is that the transformers should belong to the same vector group
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Apr 29, 2018
by
anonymous

66 views
0 answers
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Aug 13, 2019
by
Alacrity

Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in?
Last Answer : Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in loading of the transformers not in proportion to their kVA ratings.
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381 views
1 answer
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Mar 19, 2018
by
anonymous

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

Last Answer : For the parallel operation of two or more D.C. compound generators, we should ensure that series fields of all generators should be either on positive side or negative side of the armature.
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180 views
1 answer
asked
Mar 20, 2018
by
anonymous

parallel operation of MOSFET can be done more easily as compared to thyristor. why?
Last Answer : Parallel operation of MOSFET can be done more easily as compared to thyristor because the resistance of MOSFET is increases with increase in temperature. MOSFET have the positive temperature coefficient. In ... the parallel operation of MOSFET can be done more easily as compared to the thyristor.
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300 views
1 answer
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Dec 7, 2017
by
anonymous

Explain the series and parallel operation of MOSFET. Which is suitable and why?
Last Answer : Series operation of MOSFET: To increase voltage handling capability MOSFETs are connected in series. When the MOSFETs are connected in series each MOSFET should turn on and turn off ... on and turn off time and transconductance. Each MOSFET should share current equally.
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535 views
1 answer
asked
Sep 15, 2017
by
anonymous

Also, highlight the problem faced during parallel operation.
Last Answer : Parallel operation of IGBT: Parallel operation of IGBT is done for obtaining high current rating. Paralleling of IGBT reduces conduction losses and thermal stress. IGBT combines the qualities of ... . IGBTs must share losses equally otherwise IGBT may get failure due to thermal differences.
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223 views
1 answer
asked
Sep 15, 2017
by
anonymous

Give the operation of single phase full wave bridge controlled converter with RL load with a neat diagram. Also draw its waveform.
Last Answer : Single phase fully control bridge converter with RL load: 1. During positive half cycle of input voltage, T1 and T2 are forward biased and during negative half cycle, T3 and T4 are forward biased. Therefore, T1-T2 ... cycle till the firing of next pair of SCRs as shown in the waveform.
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912 views
1 answer
asked
Jul 25, 2019
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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128 views
1 answer
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May 2, 2020
by
anonymous

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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23 views
3 answers

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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545 views
1 answer
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May 21, 2020
by
anonymous
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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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586 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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98 views
1 answer
asked
May 7, 2020
by
anonymous

Explain the procedure to perform Short Circuit test on single phase transformer with circuit diagram.
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115 views
0 answers
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Apr 27, 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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267 views
6 answers
asked
Sep 2, 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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175 views
1 answer
asked
Aug 21, 2019
by
anonymous

Explain the working of a single phase capacitor start induction motor.
Last Answer : Single phase capacitor start induction motor https://youtu.be/31lvvzU5Puc
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414 views
2 answers
asked
Jul 30, 2019
by
anonymous
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Explain construction and working principle of single phase transformer.
Last Answer : A single phase transformers is an electrical device that accepts single-phase AC power and outputs single-phase AC. PRINCIPLE... The single-phase transformer works on the principle of ... and secondary windings. Thin steel laminations shall be employed to prevent power losses from the core.
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1.1k views
4 answers
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Jul 26, 2019
by
anonymous

State advantages of three phase over single phase.
Last Answer : Advantages of 3-phase system over 1-phase system: - 1. More output: For the same size, output of poly-phase machines is always higher than single phase machines. 2. Smaller size: For ... are self- starting: The three phase ac motors are self starting, while single phase induction motor are not.
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2.9k views
4 answers
asked
Aug 11, 2018
by
anonymous
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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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373 views
1 answer
asked
May 3, 2018
by
anonymous
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What is the slip (as a percentage) when a 6 pole single phase induction motor operating on 220 V and 60 Hz is rotating at speed of 1140 rpm? A) 60% B) 5% C) 10% D) None of these
Last Answer : What is the slip (as a percentage) when a 6 pole single phase induction motor operating on 220 V and 60 Hz is rotating at speed of 1140 rpm? A) 60% B) 5% C) 10% D) None of these
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127 views
1 answer
asked
Apr 29, 2018
by
anonymous

What is the power factor when a single phase watt meter operating on 200 V and 5 A for 5 hours makes 2016 revolutions and the meter constant in revolution is 420? A) 0.04 B) 1.04 C) 0.96 D) None of these
Last Answer : What is the power factor when a single phase watt meter operating on 200 V and 5 A for 5 hours makes 2016 revolutions and the meter constant in revolution is 420? A) 0.04 B) 1.04 C) 0.96 D) None of these
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210 views
1 answer
asked
Apr 29, 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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759 views
1 answer
asked
Apr 28, 2018
by
anonymous

The disc of a single phase Induction-type energy meter makes 60 revolutions in 6 minutes. Meter Constant is 1200 rev/kWh. Power consumption in the load is (A) 1.2 kW (B) 1 kW (C) 600 W (D) 500 W
Last Answer : The disc of a single phase Induction-type energy meter makes 60 revolutions in 6 minutes. Meter Constant is 1200 rev/kWh. Power consumption in the load is 500 W
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222 views
1 answer
asked
Apr 25, 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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320 views
1 answer
asked
Apr 25, 2018
by
anonymous

Last Answer : The power factor of a single phase load can be calculated if the instruments available are three ammeters or three voltmeters.
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298 views
2 answers
asked
Mar 21, 2018
by
anonymous

Last Answer : In a single phase power factor meter the phase difference between the currents in the two pressure coils is exactly 90°.
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356 views
1 answer
asked
Mar 21, 2018
by
anonymous

Last Answer : The two pressure coils of a single phase power factor meter have the same dimensions and the same number of turns.
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158 views
1 answer
asked
Mar 21, 2018
by
anonymous

Last Answer : Induction type single phase energy meters measure electric energy in kWh.
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481 views
1 answer
asked
Mar 21, 2018
by
anonymous

Last Answer : Reason is kinetic energy
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290 views
2 answers
asked
Mar 20, 2018
by
anonymous

Last Answer : If a single phase induction motor runs slower than normal, the most likely defect is worn bearings.
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170 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : Starting winding of a single phase motor of a refrigerator is disconnected from the circuit by means of a magnetic relay.
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217 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : Single phase induction motor usually operates on 0.6 power factor lagging.
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127 views
1 answer
asked
Mar 20, 2018
by
anonymous

A capacitor-start single phase induction motor is switched on to supply with its capacitor replaced by an inductor of equivalent reactance value. It will?
Last Answer : A capacitor-start single phase induction motor is switched on to supply with its capacitor replaced by an inductor of equivalent reactance value. It will not start at all.
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235 views
1 answer
asked
Mar 20, 2018
by
anonymous

The running winding of a single phase motor on testing with meggar is found to be ground. Most probable location of the ground will be?
Last Answer : The running winding of a single phase motor on testing with meggar is found to be ground. Most probable location of the ground will be at the slot edge where coil enters or comes out of the slot.
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117 views
1 answer
asked
Mar 20, 2018
by
anonymous

Last Answer : In a single phase motor the centrifugal switch disconnects auxiliary winding of the motor.
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271 views
1 answer
asked
Mar 20, 2018
by
anonymous

An unexcited single phase synchronous motor is ?
Last Answer : An unexcited single-phase synchronous motor is reluctance motor.
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167 views
1 answer
asked
Mar 18, 2018
by
anonymous

How does a single phase induction motor work?
Last Answer : As we know that single phase induction is not self started because for self started we require atleast two revolving field but single phase induction motor has only one. So we provide extra ... 1phase IM classified as split phase IM, capacitor start capacitor run, capacitor start induction run.
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124 views
1 answer
asked
Mar 17, 2018
by
anonymous

What are the five types of single phase motors used in the industry?
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79 views
0 answers
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Mar 15, 2018
by
anonymous

Explain power in single phase AC circuit.
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82 views
0 answers
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Mar 11, 2018
by
anonymous

Describe the gate circuit for a single phase full converter.
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71 views
0 answers
asked
Mar 11, 2018
by
anonymous

write short notes on single phase system.
Last Answer : A "phase" in an electrical system is often referred to as the waveform (may be voltage or the current) of the power supply. The waveform in an AC system is typically ... domestic household or commercial supplies and street lighting. Industrial supplies requires three phase electrical supply .
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107 views
1 answer
asked
Dec 12, 2017
by
anonymous
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three phase to single phase cycloconverter
Last Answer : three phase to single phase cycloconverter
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519 views
1 answer
asked
Nov 16, 2017
by
anonymous

single phase full converter
Last Answer : single phase full converter
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122 views
1 answer
asked
Nov 16, 2017
by
anonymous

explain the working of single phase induction motor.
Last Answer : Stator has two winding namely main winding and auxiliary winding.when single phase ac supply is given to the motor,its produces alternating field.this field cut by a cage rotor.so some emf ... due to this emf,rotor flux produced.the interaction between two fluxes produce torque.so rotor rotates.
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188 views
1 answer
asked
Oct 24, 2017
by
anonymous

Single Phase Induction Motor
Last Answer : Single Phase Induction Motor Single phase induction motor is mostly used in home, office, shop and many single phase appliances like pumps, ... torque and silent operation. It is uses where silent operation is required.
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528 views
1 answer
asked
Aug 9, 2017
by
anonymous

Last Answer : Winding will be damaged
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138 views
2 answers
asked
Mar 19, 2018
by
anonymous

If the percentage impedances of the two transformers working in parallel are different, then?
Last Answer : If the percentage impedances of the two transformers working in parallel are different, then parallel operation will still be possible, but the power factors at which the two transformers operate will be different from the power factor of the common load.
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135 views
1 answer
asked
Mar 19, 2018
by
anonymous

Last Answer : Natural oil cooling is used for transformers up to a rating of 3000 kVA.
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159 views
1 answer
asked
Mar 19, 2018
by
anonymous
