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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265 views
6 answers
asked
Sep 2, 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

Explain cycloconverter and its types.
Last Answer : Cycloconverter: Cycloconverter is an AC to AC converter which converts input AC into variable AC. It changes frequency. Basically, there are two types of cycloconverter one is step up ... Disadvantages of cycloconverter: So many thyristors are required in cycloconverter.
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466 views
1 answer
asked
Feb 13, 2018
by
anonymous

Explain three phase half wave controller or three phase unidirectional controller.
Last Answer : Three phase half wave controller or unidirectional controller:
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240 views
1 answer
asked
Mar 8, 2018
by
anonymous

Explain Three Phase Bidirectional Delta Connected Controller.
Last Answer : Three Phase Bidirectional Delta Connected Controller:
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484 views
1 answer
asked
Mar 7, 2018
by
anonymous

Explain three phase bridge inverter.
Last Answer : Three phase bridge inverter: Three phase bridge inverter converts DC voltage input to three-phase variable frequency variable voltage output. DC voltage source can be a DC source or output of the rectifier. ... in proper sequence. The switch may be thyristor or IGBT etc.
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476 views
1 answer
asked
Feb 19, 2018
by
anonymous

Explain three phase full wave controller.
Last Answer : Three phase full wave controller: Three phase full wave controller is also called as the three-phase bidirectional controller. Let the load is star connected so at each phase there are antiparallel connected SCRs. ... conduct at the same time and the third phase will be open.
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269 views
1 answer
asked
Feb 14, 2018
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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543 views
1 answer
asked
May 21, 2020
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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897 views
1 answer
asked
Jul 25, 2019
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

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

what is cycloconverter ?
Last Answer : Cycloconverter is a device which convert fixed AC input frequency to variable output frequency or variable input frequency to fixed output frequency.
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84 views
1 answer
asked
Aug 6, 2017
by
anonymous

Is it possible for a soil to consist only of one phase?
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2 views
0 answers

What is the operation of three phase induction motor
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7 views
0 answers

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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332 views
3 answers

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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163 views
1 answer
asked
May 7, 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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141 views
0 answers
asked
Apr 16, 2020
by
anonymous

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

Why is a three phase denoted by R, Y, B ?
Last Answer : phase 1 ,R =Red colour cable terminal, phase 2 Y=Yellow colour terminal cable,Phase 3 B=Blue colour cable terminal, N =Neutral. For identification.
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251 views
2 answers
asked
Aug 18, 2019
by
anonymous

State any four advantages of three phase induction motor.
Last Answer : Advantages of three phase induction motor https://youtu.be/27OIOCKN05U
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139 views
2 answers
asked
Jul 30, 2019
by
anonymous

Define balanced and unbalanced load in three phase circuit.
Last Answer : Balanced Load: When all the imedances of 3 phases are equal in magnitude and of same nature then load is said to be balanced. Unbalanced Load: When all the imedances of 3 phases are not equal in magnitude and of different nature then load is said to be unbalanced.
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260 views
1 answer
asked
Sep 6, 2018
by
anonymous

State any four applications of three phase circuits.
Last Answer : The application of three phase circuits are 1. Three phase circuit is used for power transmission over long distances. 2. Three phase circuit can produce rotating magnetic field 3. Three phase ... three phase Motors and Transformers. 4. Three phase circuit is used for power converters circuits.
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261 views
1 answer
asked
Aug 12, 2018
by
anonymous
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Draw the waveform of three phase AC supply voltage.
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215 views
0 answers
asked
Aug 11, 2018
by
anonymous

The slip of 400 V, three phase, 4 -pole induction motor when rotating at 1440 rpm is
Last Answer : The slip of 400 V, three phase, 4 -pole induction motor when rotating at 1440 rpm is 4 percent
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363 views
1 answer
asked
Apr 29, 2018
by
anonymous

When a V-V three phase transformer system is converted into a Δ-Δ system, increase in capacity of the system is (A) 86.6% (B) 50% (C) 57.7% (D) 73.2%
Last Answer : When a V-V three phase transformer system is converted into a Δ-Δ system, increase in capacity of the system is 73.2%
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136 views
1 answer
asked
Apr 28, 2018
by
anonymous

In a three-phase supply floating neutral is undesirable because it way give rise to?
Last Answer : In a three-phase supply floating neutral is undesirable because it way give rise to unequal line voltages across the load.
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117 views
1 answer
asked
Mar 25, 2018
by
anonymous

Three phase synchronous motor will have how many sliprings?
Last Answer : Three phase synchronous motor will have two sliprings.
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95 views
1 answer
asked
Mar 18, 2018
by
anonymous

How is a three phase cage induction motor self starting?
Last Answer : Any type of induction motor is self starting. Because the reason for torqe production require two flux displaced by some angle theta.If theta is constant with time then torqe will be constant;if ... torqe also pulsating. In induction motor this angle theta is not pulsating.so it is self starting
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160 views
1 answer
asked
Mar 17, 2018
by
anonymous

Explain power relations in three phase circuit.
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88 views
0 answers
asked
Mar 11, 2018
by
anonymous

What is mean by plugging in three phase induction motor?
Last Answer : Plugging in three-phase induction motor means interchanging of any two phases of a stator for quick stopping.
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156 views
1 answer
asked
Mar 3, 2018
by
anonymous

What is a three phase connection?
Last Answer : RYB, 440 volt/phase
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132 views
1 answer
asked
Dec 22, 2017
by
anonymous
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how can we reverse the direction of rotation of three phase induction motor ?
Last Answer : The direction of rotation of three phase induction motor can be reversed by plugging i.e by changing any two out of three phases of the supply to the stator of the Induction motor terminal.
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138 views
1 answer
asked
Oct 4, 2017
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

Single phase transformer
Last Answer : Single phase Transformer Transformer
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261 views
1 answer
asked
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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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
asked
Apr 27, 2020
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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173 views
1 answer
asked
Aug 21, 2019
by
anonymous

65 views
0 answers
asked
Aug 13, 2019
by
Alacrity
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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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407 views
2 answers
asked
Jul 30, 2019
by
anonymous

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
asked
Jul 26, 2019
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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372 views
1 answer
asked
May 3, 2018
by
anonymous

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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126 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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209 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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757 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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297 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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355 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
