Description : An alternator is feeding an infinite bus bar. Its prime mover is suddenly shut down. The alternator will: (A) Continue to work as alternator but the direction of rotation will reverse. (B) Come to stand still. (C) Continue to work as synchronous motor and direction of rotation will also be same. (D) Will work as an induction motor.
asked
Apr 5, 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 : 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 : What is design technology? Explain top down design process.
Answer :
Design technology: Design technology is the manner in which we convert our concept desired system into an implementation. The three main design technologies are 1. Compilation/Synthesis ... general purpose processors and A Gate-level Netlist for special-purpose processors.
asked
Mar 14, 2018
by
anonymous
Description : For a 15-bus power system with 3 voltage controlled buses, the size of Jacobian matrix is
Answer :
For a 15-bus power system with 3 voltage controlled buses, the size of Jacobian matrix is 25 x 25
asked
Apr 27, 2018
by
anonymous
Answer :
The single phasing relays are used for the protection of three phase motors.
asked
Mar 20, 2018
by
anonymous
Answer :
The steady state stability of the power system can be increased by connecting lines in parallel.
asked
Mar 20, 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 : 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 : When the north poles of two bar magnets are brought close together, there will be: A. no force B. a downward force C. a force of attraction D. a force of repulsion
Answer :
When the north poles of two bar magnets are brought close together, there will be: a force of repulsion
asked
Apr 12, 2018
by
anonymous
Description : Explain buck or step down converter and draw its waveforms.
Answer :
Buck converter or Step down converter: Buck converter is a step-down converter. The buck converter step-down the output voltage and step up the output current. Buck converter is a DC to DC converter. ... load. The output voltage is controlled by controlling on period and off period.
asked
Feb 12, 2018
by
anonymous
Description : If a 5-bus test system contains 6 transmission lines and one transformer, how many non-zero elements are there in the system Y-bus ? (A) 25 (B) 12 (C) 11 (D) 19
Answer :
If a 5-bus test system contains 6 transmission lines and one transformer, 19 non-zero elements are there in the system Y-bus.
asked
Apr 28, 2018
by
anonymous
Description : What are the components of system bus? A) CPU Bus, Address Bus, Data Bus B) Memory, Control Unit, ALU C) Data Bus, Address Bus, Control Bus D) Register, PC, IR
Answer :
What are the components of system bus? A) CPU Bus, Address Bus, Data Bus B) Memory, Control Unit, ALU C) Data Bus, Address Bus, Control Bus D) Register, PC, IR
asked
Jun 18, 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
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
Description : lf the poles of system are lying on the imaginary axis in s-plane, then the system will be
Answer :
lf the poles of system are lying on the imaginary axis in s-plane, then the system will be marginally stable
asked
Apr 26, 2018
by
anonymous
Description : The damping factor of a particular system is unity, the system response will be
Answer :
The damping factor of a particular system is unity, the system response will be critically damped
asked
Apr 26, 2018
by
anonymous
Description : A lightening arrester connected between the line and earth in a power system (1) protects the terminal equipment against travelling surges (2) protects the transmission line against direct lightening strokes (3) suppresses high frequency oscillations in the line (4) reflects back the travelling wave approaching it
Answer :
A lightening arrester connected between the line and earth in a power system protects the terminal equipment against travelling surges
asked
Apr 29, 2018
by
anonymous
Description : In quadrilateral speed-time curve of electric traction system, the accelerations during successive time periods are ______ respectively. (A) positive, negative and negative (B) positive, zero and negative (C) positive, positive and negative (D) positive, negative and zero
Answer :
In quadrilateral speed-time curve of electric traction system, the accelerations during successive time periods are positive, negative and negative respectively.
asked
Apr 30, 2018
by
anonymous
Answer :
Air blast circuit breakers for 400 kV power system are designed to operate in 50 millisecond.
asked
Mar 20, 2018
by
anonymous
Answer :
The contacts of high voltage switches used in power system are submerged in oil. The main purpose of the oil is to extinguish the arc.
asked
Mar 20, 2018
by
anonymous
Description : With fault clearing time, the transient stability of a power system
Answer :
With fault clearing time, the transient stability of a power system decreases
asked
Apr 27, 2018
by
anonymous
Answer :
A balanced 3-phase system consists of positive sequence currents.
asked
Mar 20, 2018
by
anonymous
Answer :
Ungrounded neutral transmission system is not recommended because of system insulation being overstressed due to over voltages, insulation overstress may lead to failure and subsequent phase to phase faults, being inadequately protected against ground fault.
asked
Mar 20, 2018
by
anonymous
Description : The sequence components of current of a single-phase load connected to a 3-phase system are (A) equal positive and negative sequence components (B) equal positive, negative and zero sequence components (C) vector sum of sequence currents is zero (D) algebraic sum of sequence currents is zero
Answer :
The sequence components of current of a single-phase load connected to a 3-phase system are equal positive, negative and zero sequence components
asked
Apr 28, 2018
by
anonymous
Answer :
Source transformation Replace the circuit with voltage source in series with a single resistor
asked
Mar 21, 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
asked
Aug 13, 2019
by
Alacrity
Description : In a single crystal of an intrinsic semiconductor, the number of free carriers at the Fermi level at room temperature is: A) Half the total number of electrons in the crystal B) Zero C) Half the number of atoms in the crystal D) Half the number of free electrons in the crystal
Answer :
In a single crystal of an intrinsic semiconductor, the number of free carriers at the Fermi level at room temperature is: Zero
asked
Jun 18, 2018
by
anonymous
Description : In a 16-bit microprocessor, a single word is A) 16 bit data B) 32 bit data C) 8 bit data D) 64 bit data
Answer :
In a 16-bit microprocessor, a single word is 16 bit data
asked
Jun 18, 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 : A single force and a couple acting in the same plane upon a rigid body?
Answer :
A single force and a couple acting in the same plane upon a rigid body cannot balance each other.
asked
Mar 22, 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 :
In a single phase motor the centrifugal switch disconnects auxiliary winding of the motor.
asked
Mar 20, 2018
by
anonymous
Answer :
Induction type single phase energy meters measure electric energy in kWh.
asked
Mar 21, 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 : When there is one buyer and many sellers then that situation is called (1) Monopoly (2) Single buyer right (3) Down right (4) Double buyers right
Answer :
Single buyer right
Description : 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%
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%
asked
Apr 28, 2018
by
anonymous
Description : Describe control of a single lamp from three places. Draw the relevant circuit diagram.
Answer :
Single lamp control from three places- It consists of two way switches & intermediate switch, the circuit diagram is as shown in figure. We require two 2-way switches and one intermediate switch and a lamp ... position of any one switch is changed, then the lamp will be turned off.
asked
May 3, 2020
by
anonymous
Description : Illustrate with neat wiring diagram a single lamp control by two point method.
Answer :
Single lamp control by two point method: This system is commonly used for stair case wiring. It consists of two way switches (the switch operates always in one of the two possible positions) the ... the person will change the position of switch S2, so that the lamp will be switched OFF'.
asked
May 3, 2020
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 : 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 : 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 : A single core lead sheathed cable with two dielectrics of permittivity 4 and 3, respectively, are subjected to same maximum stress. If the conductor diameter is 1.5 cm, the outer diameter of the first dielectric is (A) 1.125 cm (B) 1.5 cm (C ) 2 cm (D) 8 cm
Answer :
A single core lead sheathed cable with two dielectrics of permittivity 4 and 3, respectively, are subjected to same maximum stress. If the conductor diameter is 1.5 cm, the outer diameter of the first dielectric is 2 cm
asked
Apr 28, 2018
by
anonymous
Description : A switch tail ring counter is made by using a single D-FF. The resulting circuit is (A) T-FF (B) D-FF (C) SR-FF (D) JK-FF
Answer :
A switch tail ring counter is made by using a single D-FF. The resulting circuit is T-FF
asked
Apr 28, 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 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
Answer :
If a single phase induction motor runs slower than normal, the most likely defect is worn bearings.
asked
Mar 20, 2018
by
anonymous