Description : Power Electronic Devices
asked
Apr 20, 2020
by
anonymous
Description : What arc the errors occurring in measuring devices due to stray magnetic field and temp '? Explain how to compensate them.
Answer :
1. Error due to stray magnetic fields- Main magnetic field gets disturbed by external magnetic fields known as stray magnetic fields. 2. Compensation technique To avoid this error, ... resistance alloy having a negligible resistance temp coefficient in the ratio of 1:10 for pressure coil
asked
Sep 6, 2018
by
anonymous
Description : What are examples of telecommunication devices?
asked
Mar 10, 2018
by
anonymous
Description : What is a switching impulse?
asked
Mar 10, 2018
by
anonymous
Description : Explain the concept of initial and final conditions in switching for L and C.
Answer :
i) Inductor: The current through an inductor cannot change instantly. If the inductor current is zero just before switching, then whatever may be the applied voltage, just after switching the inductor ... open-circuit. The initial and final conditions are summarized in following table:
asked
Sep 7, 2018
by
anonymous
Description : Switching of a lamp in house produces noise in the radio. This is because switching operation produces?
Answer :
Switching of a lamp in house produces noise in the radio. This is because switching operation produces arcs across separating contacts.
asked
Mar 25, 2018
by
anonymous
Description : Explain series switching control of AC load. Single phase resistance load - Integral half cycle control Phase control - Resistance load
asked
Mar 11, 2018
by
anonymous
Description : Explain switching model of MOSFET.
asked
Mar 10, 2018
by
anonymous
Description : Explain space vector transformation and space vector switching with the help of diagram. What are the advantages of SVM?
asked
Mar 10, 2018
by
anonymous
asked
Sep 14, 2018
by
anonymous
Description : What are the disadvantages of the linear regulator? how are they overcome in the switching regulator? What is continuous and discontinuous mode switching regulator?
Answer :
Disadvantages of the linear regulator: Linear regulator waste power in the form of heat. Linear regulator has very low efficiency. Linear regulator cannot be used for the step ... between continuous mode and discontinuous mode switching regulator.
asked
Feb 11, 2018
by
anonymous
Description : Draw the structural diagram of GTO. Explain briefly the switching behavior of GTO with the help of appropriate voltage and current waveform.
Answer :
Gate Turn Off Thyristor (GTO) Conventional Thyristor can be turned on with gate terminal but can not turn off from gate terminal. But in case of Gate Turn Off Thyristor (GTO), we can turn it on and off ... subdivided as storage period (Ts), fall period (Tp) and tail period (Tt).
Description : The resolving power of a spectrometer consisting of collimator, a grating and a telescope can be increased by (A) increasing the angular magnification of the telescope (B) increasing the period of the grating (C) decreasing the period of the grating (D) decreasing the slit-width of the collimator
Answer :
The resolving power of a spectrometer consisting of collimator, a grating and a telescope can be increased by decreasing the period of the grating
asked
Apr 26, 2018
by
anonymous
Description : What are the types of power losses in inductor?
Answer :
Copper losses, Eddy current loss, and hysteresis loss are the types of power losses in inductor.
asked
Mar 8, 2018
by
anonymous
asked
Mar 20, 2020
by
anonymous
Description : What is meant by power dip?
asked
Mar 10, 2018
by
anonymous
Description : What is meant by feeder in power system?
Answer :
A feeder line is a peripheral route or branch in a network which connects smaller or more remote nodes with a route or branch carrying heavier traffic. The term is applicable to any system based on a hierarchical network.
asked
Mar 10, 2018
by
anonymous
Description : A waveguide termination having VSWR of 1.1 is used to dissipate 100 watts of power. The reflected power will be A) 0.2268 W B) 0.5868 W C) 0.3468 W D) 0.4568 W
Answer :
A waveguide termination having VSWR of 1.1 is used to dissipate 100 watts of power. The reflected power will be 0.2268 W
asked
Jun 18, 2018
by
anonymous
Description : The total power of an AM transmitter having a carrier power of 50 W and the percentage of modulation at 80% is A) 50 W B) 66 W C) 68 W D) 70 W
Answer :
The total power of an AM transmitter having a carrier power of 50 W and the percentage of modulation at 80% is 66 W
asked
Jun 18, 2018
by
anonymous
Description : A snubber circuit is connected to the power semiconductor device to reduce the (A) turn-on time (B) turn-off time (C) electrical stresses (D) thermal resistance
Answer :
A snubber circuit is connected to the power semiconductor device to reduce the electrical stresses
asked
Apr 28, 2018
by
anonymous
Answer :
MOSFET have high current losses due to High on state resistance. Hence MOSFET is used for low power applications.
asked
Sep 22, 2017
by
anonymous
Answer :
Find power delivered by voltage source
asked
Mar 21, 2020
by
anonymous
Description : Explain energy conservation technique “by improving power quality” for induction motor.
Answer :
Energy conservation method in induction motor by improving power quality: Electrical energy can be conserved by improving the power quality. It can be achieved by avoiding voltage unbalance, maintaining ... losses can be minimized by using harmonic filter thus reducing the harmonics in the system.
asked
Sep 22, 2018
by
anonymous
Description : _______ electric power is the most common method used by electrical grids to transfer power. (A) One-phase (B) Two-phase (C) Three-phase (D) None of the above
Answer :
Three-phase electric power is the most common method used by electrical grids to transfer power.
asked
May 8, 2018
by
anonymous
Description : The stability of the power system is not affected by (1) generator reactance (2) line reactance (3) line losses (4) output torque
Answer :
The stability of the power system is not affected by line losses
asked
Apr 30, 2018
by
anonymous
Description : In voltage source converter based HVDC transmission system the active power is controlled by changing (A) phase angle of the converter ac input voltage (B) supply frequency of the converter ac input voltage (C) magnitude of the converter ac input voltage (D) DC voltage at the inverter terminals
Answer :
In voltage source converter based HVDC transmission system the active power is controlled by changing phase angle of the converter ac input voltage
asked
Apr 28, 2018
by
anonymous
Description : The power consumed by a balanced 3-ph load is measured by two-wattmeter method. The meter readings are 8 kW and 4 kW. The power factor of the load is (A) zero (B) 0.5 (C) between zero and 0.5 (D) between 0.5 and unity
Answer :
The power consumed by a balanced 3-ph load is measured by two-wattmeter method. The meter readings are 8 kW and 4 kW. The power factor of the load is between 0.5 and unity
asked
Apr 28, 2018
by
anonymous
Description : steady-state stability of a power system is improved by
Answer :
steady-state stability of a power system is improved by using double circuit line instead of single circuit line
asked
Apr 28, 2018
by
anonymous
Description : The mechanical power developed by the armature of a d.c. motor is equal to?
Answer :
The mechanical power developed by the armature of a d.c. motor is equal to armature current multiplied by back e.m.f.
asked
Mar 26, 2018
by
anonymous
Description : The apparent power drawn by an A.C. circuit is 10 kVA and active power is 8 kW. The reactive power in the circuit is?
Answer :
The apparent power drawn by an A.C. circuit is 10 kVA and active power is 8 kW. The reactive power in the circuit is 6 kVAR.
asked
Mar 25, 2018
by
anonymous
Description : The input of an A.C. circuit having power factor of 0.8 lagging is 40 kVA The power drawn by the circuit is?
Answer :
The input of an A.C. circuit having power factor of 0.8 lagging is 40 kVA The power drawn by the circuit is 32 kW.
asked
Mar 25, 2018
by
anonymous
Description : Power factor of an inductive circuit is usually improved by connecting capacitor to it in?
Answer :
Power factor of an inductive circuit is usually improved by connecting capacitor to it in parallel.
asked
Mar 25, 2018
by
anonymous
Answer :
In case of locomotives the tractive power is provided by double cylinder, double acting steam engine.
asked
Mar 22, 2018
by
anonymous
Answer :
The electrical power to a meggar is provided by permanent magnet D.C. generator.
asked
Mar 21, 2018
by
anonymous
Description : In a 3-phase power measurement by two wattmeter method the reading of one of the wattmeter was zero. The power factor of the load must be?
Answer :
In a 3-phase power measurement by two wattmeter method the reading of one of the wattmeter was zero. The power factor of the load must be 0.5.
asked
Mar 21, 2018
by
anonymous
Description : In a 3-phase power measurement by two wattmeter method, both the watt meters had identical readings. The power factor of the load was?
Answer :
In a 3-phase power measurement by two wattmeter method, both the watt meters had identical readings. The power factor of the load was unity.
asked
Mar 21, 2018
by
anonymous
Answer :
The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is 0.5.
asked
Mar 20, 2018
by
anonymous
Answer :
Approximate estimation of power demand can be made by load survey method, statistical methods, mathematical method, economic parameters.
asked
Mar 20, 2018
by
anonymous
Answer :
The inductive interference between power and communication line can be minimized by transposition of the power line, transposition of the communication line.
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 : The maximum load that a power transformer can carry is limited by its?
Answer :
The maximum load that a power transformer can carry is limited by its voltage ratio.
asked
Mar 19, 2018
by
anonymous
Description : Active power and apparent power are represented by?
Answer :
Active power and apparent power are represented by kW and kVA.
asked
Mar 19, 2018
by
anonymous
Description : How much electricity is produced by a power plant?
asked
Mar 10, 2018
by
anonymous
Answer :
Yes, we can make the power factor of synchronous motor leading by adjusting its excitation.
asked
Mar 6, 2018
by
anonymous
Description : An SSB transmitter produces a peak-to-peak voltage of 200 V across a 100 Ω antenna load. What is the Peak Envelope Power? A) 49.98 W B) 79.98 W C) 99.96 W D) 199.93 W
Answer :
An SSB transmitter produces a peak-to-peak voltage of 200 V across a 100 Ω antenna load. What is the Peak Envelope Power? A) 49.98 W B) 79.98 W C) 99.96 W D) 199.93 W
asked
Jun 18, 2018
by
anonymous
Description : What is the value of capacitance required to improve power factor from 0.7 to 0.9. Given that: Real power = 50 W Vrms of the source = 120 Frequency = 50 Hz #powerfactor
asked
May 17, 2020
by
anonymous
Description : What are the basic requirements of locating wind power plant ?
Answer :
The basic requirements of locating wind power plant: 1) The site should be selected where winds are strong i.e. where pressure of wind is high and there is continuity. 2) Wind pressure ... the turbine which can affect the system's overall performance. 10)Possibility to connect to power grid.
asked
Aug 2, 2019
by
anonymous
Description : What are the criteria for selection of site for hydroelectric power plant?
Answer :
Following Factors to be kept while site selecting for Hydro power plant: 1. It should be located where high rain fall occurs. 2. A large catchments area must be available to store water. 3. It ... 12. Cost of land should be less. 13. Skilled and unskilled man power should be available nearby.
asked
Jul 24, 2019
by
anonymous
Description : Options: A) WATT B) AMPERE C) VOLTS D) OHM
Answer :
Correct Answer: A) WATT
asked
Jun 28, 2019
by
anonymous
asked
Nov 6, 2018
by
Power system