Description : An additional condition for parallel operation of three-phase transformers over single-phase transformers is that
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
asked
Apr 29, 2018
by
anonymous
asked
Aug 13, 2019
by
Alacrity
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.
asked
Mar 20, 2018
by
anonymous
Description : Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in?
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.
Description : parallel operation of MOSFET can be done more easily as compared to thyristor. why?
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.
asked
Dec 7, 2017
by
anonymous
Description : Explain the series and parallel operation of MOSFET. Which is suitable and why?
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.
asked
Sep 15, 2017
by
anonymous
Description : Also, highlight the problem faced during parallel operation.
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.
asked
Sep 15, 2017
by
anonymous
Description : Single phase transformer
Answer :
Single phase Transformer Transformer
asked
May 16, 2020
by
anonymous
Description : Give the operation of single phase full wave bridge controlled converter with RL load with a neat diagram. Also draw its waveform.
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.
asked
Jul 25, 2019
by
anonymous
Description : Draw single phase full wave mid-point converter for inductive load. Draw input and output waveforms for it.
Answer :
Circuit Diagram: Waveforms:
asked
May 21, 2020
by
anonymous
Description : Draw the single stage RC coupled amplifier circuit and explain its’s operation.
Answer :
Operation:- The capacitors C1 and C2 are called as the coupling capacitors. As the load resistor RL (not shown in the diagram) is coupled to the amplifier through the coupling capacitor ... connected in the common emitter (CE) configuration. Therefore, this amplifier is called CE amplifier.
asked
Sep 4, 2018
by
anonymous
Answer :
The two pressure coils of a single phase power factor meter have the same dimensions and the same number of turns.
asked
Mar 21, 2018
by
anonymous
Answer :
Reason is kinetic energy
asked
Mar 20, 2018
by
anonymous
Description : State suitable single phase motor for following applications: (i) Table fan (ii) Mixers and Grinders
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
asked
May 7, 2020
by
anonymous
Description : 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
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
asked
Apr 29, 2018
by
anonymous
Description : 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
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
asked
Apr 28, 2018
by
anonymous
Description : Describe the gate circuit for a single phase full converter.
asked
Mar 11, 2018
by
anonymous
Description : Draw & explain operation of phase detector.
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.
asked
May 2, 2020
by
anonymous
Description : Explain MCB and ELCB with connection diagram supplying single phase load.
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.
asked
May 7, 2020
by
anonymous
Description : Explain the procedure to perform Short Circuit test on single phase transformer with circuit diagram.
asked
Apr 27, 2020
by
anonymous
Description : Why is a capacitor used in a single phase motor and not in three phase motor ?
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.
asked
Sep 2, 2019
by
anonymous
Description : working principle of single phase motor
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.
asked
Aug 21, 2019
by
anonymous
Description : Explain the working of a single phase capacitor start induction motor.
Answer :
Single phase capacitor start induction motor https://youtu.be/31lvvzU5Puc
asked
Jul 30, 2019
by
anonymous
Description : Explain construction and working principle of single phase transformer.
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.
asked
Jul 26, 2019
by
anonymous
Description : State advantages of three phase over single phase.
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.
asked
Aug 11, 2018
by
anonymous
Description : 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
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
asked
May 3, 2018
by
anonymous
Description : 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
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
asked
Apr 29, 2018
by
anonymous
Description : 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
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
asked
Apr 25, 2018
by
anonymous
Description : 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%
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%
asked
Apr 25, 2018
by
anonymous
Answer :
The power factor of a single phase load can be calculated if the instruments available are three ammeters or three voltmeters.
asked
Mar 21, 2018
by
anonymous
Answer :
In a single phase power factor meter the phase difference between the currents in the two pressure coils is exactly 90°.
asked
Mar 21, 2018
by
anonymous
Answer :
Induction type single phase energy meters measure electric energy in kWh.
asked
Mar 21, 2018
by
anonymous
Answer :
If a single phase induction motor runs slower than normal, the most likely defect is worn bearings.
asked
Mar 20, 2018
by
anonymous
Answer :
Starting winding of a single phase motor of a refrigerator is disconnected from the circuit by means of a magnetic relay.
asked
Mar 20, 2018
by
anonymous
Answer :
Single phase induction motor usually operates on 0.6 power factor lagging.
asked
Mar 20, 2018
by
anonymous
Description : 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?
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.
asked
Mar 20, 2018
by
anonymous
Description : 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?
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.
asked
Mar 20, 2018
by
anonymous
Answer :
In a single phase motor the centrifugal switch disconnects auxiliary winding of the motor.
asked
Mar 20, 2018
by
anonymous
Description : An unexcited single phase synchronous motor is ?
Answer :
An unexcited single-phase synchronous motor is reluctance motor.
asked
Mar 18, 2018
by
anonymous
Description : How does a single phase induction motor work?
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.
asked
Mar 17, 2018
by
anonymous
Description : What are the five types of single phase motors used in the industry?
asked
Mar 15, 2018
by
anonymous
Description : Explain power in single phase AC circuit.
asked
Mar 11, 2018
by
anonymous
Description : write short notes on single phase system.
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 .
asked
Dec 12, 2017
by
anonymous
Description : three phase to single phase cycloconverter
Answer :
three phase to single phase cycloconverter
asked
Nov 16, 2017
by
anonymous
Description : single phase full converter
Answer :
single phase full converter
asked
Nov 16, 2017
by
anonymous
Description : explain the working of single phase induction motor.
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.
asked
Oct 24, 2017
by
anonymous
Description : Single Phase Induction Motor
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.
Answer :
Winding will be damaged
asked
Mar 19, 2018
by
anonymous
Description : If the percentage impedances of the two transformers working in parallel are different, then?
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.
asked
Mar 19, 2018
by
anonymous
Description : State any two conditions for parallel operation of 3-phase transformer.
Answer :
Conditions for Parallel operation of 3 phase transformer 1) Voltage ratings of both the transformers must be identical. 2) Percentage or p.u. impedance should be equal in magnitude. 3) X/R ratio ... between primary & secondary voltages must be same. 6) Phase sequence on both sides must be same.