A dc chopper is fed from a constant voltage mains the duty ratio of chopper is progressively increased while the chopper feeds an RL load. The per unit current ripple would (1) increase progressively (2 ... 0.5 and then increase (4) increase to a maximum value at α = 0.5 and then decrease
Last Answer : A dc chopper is fed from a constant voltage mains the duty ratio of chopper is progressively increased while the chopper feeds an RL load. The per unit current ripple would increase to a maximum value at α = 0.5 and then decrease
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1 answer
asked
Apr 30, 2018
by
anonymous

Last Answer : Yes, we can use triac in the multi-quadrant chopper.
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221 views
1 answer
asked
Mar 6, 2018
by
anonymous

Explain two-quadrant chopper.........
Last Answer : Two quadrant chopper: There are two semiconductor controllable switches in the two-quadrant chopper. Two quadrant type A chopper: The figure shows the type A chopper. Both the switch never turn on at ... 2 are turned on then Vo=Vs. When chopper 1 and chopper 2 are off then Vo=-Vs.
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575 views
1 answer
asked
Feb 15, 2018
by
anonymous

Last Answer : By using some circuit the forward DC current of thyristor is forced to zero is called forced commutation.
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118 views
1 answer
asked
Sep 21, 2017
by
anonymous

Last Answer : Natural commutation is also called as line Communication. The turning off of thyristor due to AC supply is called natural commutation or line commutation. If the thyristor is connected to AC supply ... connected to positive and anode terminal get connected to negative, this turns off the thyristor.
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110 views
1 answer
asked
Sep 21, 2017
by
anonymous

Last Answer : Thyristor commutation means turning off thyristor.
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145 views
1 answer
asked
Sep 10, 2017
by
anonymous

For a class D commutation, answer the following: i) Explain the operation with circuit diagram. ii) Interpret with waveforms.
Last Answer : Class D commutation: This is also called as auxiliary commutation because it uses an auxiliary SCR to switch the charged capacitor across conducting SCR to turn it off. In this scheme, the main ... make SCR1 forward biased and keep ready for next triggering. The above cyclic process is repeated.
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194 views
1 answer
asked
May 21, 2020
by
anonymous

Draw circuit diagram of Class B commutation.
Last Answer : Class B: Resonant Pulse Commutation:
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119 views
1 answer
asked
May 21, 2020
by
anonymous

Differentiate between Natural and Forced commutation
Last Answer : Natural commutation Forced commutation Source is AC Source is DC External commutating componants are not required External commutating componants are required SCR turns off ... in controlled rectifiers, AC voltage controllers etc. Used in choppers & inverters etc
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1.9k views
1 answer
asked
Oct 13, 2019
by
anonymous

Class D commutation
Last Answer : Class D commutation: This is also called as auxiliary commutation because it uses an auxiliary SCR to switch the charged capacitor across conducting SCR to turn it off. In this scheme, the main ... make SCR1 forward biased and keep ready for next triggering. The above cyclic process is repeated.
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162 views
1 answer
asked
Oct 13, 2019
by
anonymous

Explain auxiliary commutation with a neat diagram. Also draw its waveform.
Last Answer : Auxiliary Commutation At start, the Ta is triggered and turned on to carry the load current. Due to the resonant circuit R-L-C, the current initially rises, attains peak and then falls to ... , the firing of auxiliary SCR commutates the main SCR, hence name is auxiliary commutation.
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277 views
1 answer
asked
Jul 25, 2019
by
anonymous

Define commutation. Give the types of commutation.
Last Answer : Commutation: The process of turning-off a conducting thyristor is called commutation . Types of Commutation: i) Line commutation (Natural commutation) ii) Load commutation iii) Forced commutation iv) ... Auxiliary commutation v) Class E: External pulse commutation vi) Class F: AC line commutation
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1 answer
asked
Jul 25, 2019
by
anonymous

An FET is a better chopper than a BJT because it has (A) lower offset voltage (B) higher series ON resistance (C) lower input current (D) higher input impedance
Last Answer : An FET is a better chopper than a BJT because it has lower offset voltage
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681 views
1 answer
asked
Apr 26, 2018
by
anonymous

Chopper controlled DC motor
Last Answer : Chopper controlled DC motor
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239 views
1 answer
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Aug 25, 2017
by
anonymous

Class A Load Commutation
Last Answer : Class A: Load Commutation: The class A or load commutation (also called self-commutation or resonant commutation) is employed in thyristor circuits supplied from DC source. The commutating components include ... biased. Thus the zero-current and reverse-bias cause the thyristor to turn-off.
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178 views
1 answer
asked
Oct 13, 2019
by
anonymous

Draw a neat circuit diagram of class F commutation
Last Answer : class F commutation
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1 answer
asked
Oct 13, 2019
by
anonymous

In a 3-phase converter circuit during commutation when one SCR in one phase is turned on to turn-off an SCR in another phase, results in (A) voltage notching (B) harmonic distortion (C) voltage sag (D) voltage swell
Last Answer : In a 3-phase converter circuit during commutation when one SCR in one phase is turned on to turn-off an SCR in another phase, results in voltage notching
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174 views
1 answer
asked
Apr 28, 2018
by
anonymous

Last Answer : Satisfactory commutation of D.C. machines requires brushes should be of proper grade and size, brushes should smoothly run in the holders, smooth, concentric commutator properly undercut.
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108 views
1 answer
asked
Mar 20, 2018
by
anonymous

What are the different types of chopper with respect to commutation process?
Last Answer : a. Voltage commutated chopper. b. Current commutated chopper. c. Load commutated chopper.
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1 answer

Which of the following problem arises in D.C. motors which are fed from thyristor bridge circuits ? (a) Increased I R losses (b) Increased core losses (c) Poor commutation (d) Change in motor parameters (e) All of the above
Last Answer : (e) All of the above
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1 answer

Natural commutation means: A) reducing the thyristor current to zero B) reducing the thyristor current below “holding current” C) reducing the current to zero and allowing time to recover thyristor junctions D) none of (A), (B) and (C)
Last Answer : Natural commutation means: reducing the current to zero and allowing time to recover thyristor junctions
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102 views
1 answer
asked
Jun 4, 2018
by
anonymous

Which of the following is also called as voltage commutation? (a) CLASS A (b) CLASS B (c) CLASS C (d) CLASS D
Last Answer : Which of the following is also called as voltage commutation? (a) CLASS A (b) CLASS B (c) CLASS C (d) CLASS D
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96 views
1 answer
asked
May 13, 2018
by
anonymous

The duty ratio of a step-up chopper with an output voltage of 200 V from a 80 V dc source, is (A) 0.4 (B) 0.5 (C ) 0.6 (D) 1.5
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93 views
0 answers
asked
Jun 4, 2018
by
anonymous

Is gate turn on mechanism of GTO is similar to conventional thyristor?
Last Answer : Yes gate turn on mechanism of GTO is similar to conventional thyristor.
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241 views
1 answer
asked
Jun 22, 2018
by
anonymous

A thyristor is triggered by a pulse train of 5 kHz. The duty ratio is 0.4. If the allowable average power is 100 W, the maximum allowable gate drive power will be
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150 views
0 answers
asked
May 25, 2018
by
anonymous

In a thyristor, the magnitude of anode current will:
Last Answer : In a thyristor, the magnitude of anode current will: Not change with any variation in gate current
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127 views
1 answer
asked
May 22, 2018
by
anonymous

A thyristor (SCR) turns off when the A) Gate pulse is removed B) Gate pulse is applied C) Thyristor current is below holding value D) Anode voltage is made negative
Last Answer : A thyristor (SCR) turns off when the Thyristor current is below holding value
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1 answer
asked
May 20, 2018
by
anonymous

Turn-on of a thyristor (SCR) takes place when A) Anode to cathode voltage is positive B) Anode to cathode voltage is negative C) Positive current is applied to gate D) Anode to cathode voltage is positive and positive current pulse is applied to gate
Last Answer : Turn-on of a thyristor (SCR) takes place when Anode to cathode voltage is positive and positive current pulse is applied to gate
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226 views
1 answer
asked
May 20, 2018
by
anonymous

The number of p-n junctions in a thyristor are A)1 B) 2 C) 3 D) 4
Last Answer : The number of p-n junctions in a thyristor are 3
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410 views
1 answer
asked
May 20, 2018
by
anonymous

Anode current in an thyristor is made up of (A) electrons only (B) electrons or holes (C) electrons and holes (D) holes only
Last Answer : Anode current in an thyristor is made up of electrons and holes
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311 views
1 answer
asked
May 17, 2018
by
anonymous

In a thyristor, holding current is (a) More than latching current IL (b) Less than IL (c) Equal to IL (d) Very small
Last Answer : In a thyristor, holding current is Less than IL
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1 answer
asked
May 13, 2018
by
anonymous

Thyristor can be protected from over voltages by using
Last Answer : Thyristor can be protected from over voltages by using Voltage clamping device
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108 views
1 answer
asked
May 8, 2018
by
anonymous

Leakage current flows through the thyristor in
Last Answer : Leakage current flows through the thyristor in Forward blocking mode and Reverse blocking mode.
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211 views
1 answer
asked
May 8, 2018
by
anonymous

What is a phase control thyristor?
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0 answers
asked
Mar 19, 2018
by
anonymous
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Why thyristor are not preferred for inverter?
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0 answers
asked
Mar 19, 2018
by
anonymous

What is thyristor family?
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asked
Mar 19, 2018
by
anonymous

What is meant by firing angle of thyristor?
Last Answer : The point at which SCR is triggered is known as firings angle of thyristor.
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234 views
1 answer
asked
Mar 19, 2018
by
anonymous

What is the use of a thyristor in a circuit?
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0 answers
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Mar 19, 2018
by
anonymous

What is a reverse conducting thyristor?
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87 views
0 answers
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Mar 19, 2018
by
anonymous

What is the function of a thyristor?
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0 answers
asked
Mar 19, 2018
by
anonymous

Why SCR is called as thyristor?
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97 views
0 answers
asked
Mar 19, 2018
by
anonymous

Is a SCR a thyristor?
Last Answer : Yes, SCR is a thyristor. Thyristor is the family and SCR is the member of that family but SCR is universally known as thyristor.
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162 views
1 answer
asked
Mar 19, 2018
by
anonymous

How is a thyristor used to convert AC to DC?
Last Answer : thyristor
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123 views
1 answer
asked
Mar 19, 2018
by
anonymous

What is the application of thyristor?
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90 views
0 answers
asked
Mar 19, 2018
by
anonymous

Last Answer : Yes ,it is one of the main advantage using thristors as a switch in DC circuit ,it has a high current gain
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161 views
2 answers
asked
Mar 6, 2018
by
anonymous

Explain thyristor gate drive circuit.
Last Answer : Thyristor Gate Drive Circuit: The thyristor can be turned on by pulse voltage signal at gate terminal and it does not require continuous drive signal like the transistor. The gate ... circuit provide required minimum gate voltage and gate current then the thyristor conducts properly.
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3.0k views
1 answer
asked
Feb 19, 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
asked
Dec 7, 2017
by
anonymous

what are the disadvantages of thyristor?
Last Answer : Disadvantages of thyristor The silicon controlled rectifier (SCR) is unidirectional devices, so it can control power only in DC power during positive half cycle of AC supply. Thus only DC power is ... cycle. It cannot be used at higher frequencies. The gate current cannot be negative
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888 views
2 answers
asked
Dec 6, 2017
by
anonymous

write short notes on thyristor CSI .
Last Answer : Current-source inverter (CSI) is an inverter with a DC current input. Current source inverters are most commonly used in very high power AC motor drives.
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107 views
2 answers
asked
Nov 15, 2017
by
anonymous

Draw the structural diagram of GTO. Explain briefly the switching behavior of GTO with the help of appropriate voltage and current waveform.
Last 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).
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1 answer
asked
Aug 8, 2017
by
anonymous
