Last Answer : By using some circuit the forward DC current of thyristor is forced to zero is called forced commutation.
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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

In a thyristor D.C. chopper, which type of commutation results in best performance ?
Last Answer : voltage commutation
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4.9k views
2 answers
asked
Dec 31, 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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195 views
1 answer
asked
May 21, 2020
by
anonymous
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Draw circuit diagram of Class B commutation.
Last Answer : Class B: Resonant Pulse Commutation:
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121 views
1 answer
asked
May 21, 2020
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

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

Draw a neat circuit diagram of class F commutation
Last Answer : class F commutation
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111 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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278 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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214 views
1 answer
asked
Jul 25, 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

Last Answer : Thyristor have three terminals anode, cathode and Gate.
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1 answer
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Sep 21, 2017
by
anonymous

thyristor can be turned off by?
Last Answer : Thyristor can be turned off by making anode potential equal to cathode potential or by making anode potential less than cathode potential.
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135 views
1 answer
asked
Sep 10, 2017
by
anonymous

Last Answer : Thyristor can only be turned on by small gate pulse but it cannot be turn off by using gate hence thyristor is called semi controlled device.
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1.1k views
1 answer
asked
Sep 10, 2017
by
anonymous

Last Answer : Thyristor can be turn on by positive gate pulse and the current will continue to flow through the device even when the gate voltage is low hence thyristor is called latching device.
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918 views
1 answer
asked
Sep 10, 2017
by
anonymous

Describe the working principle of Thyristor operated dimmer with the help of circuit diagram.
Last Answer : Thyristor operated dimmer: A popular thyristor operated dimmer circuit employ TRIAC-DIAC phase control for low AC power control. During each half-cycle, the capacitor charges through (R1+VR1). When the ... time constant {C (R1+VR1)}. Thus by reducing VR1 the lamp brightness can be increased.
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368 views
1 answer
asked
May 3, 2020
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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153 views
0 answers
asked
Mar 19, 2018
by
anonymous
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Why thyristor are not preferred for inverter?
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455 views
0 answers
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Mar 19, 2018
by
anonymous
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What is thyristor family?
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67 views
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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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235 views
1 answer
asked
Mar 19, 2018
by
anonymous

What is the use of a thyristor in a circuit?
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2.9k views
0 answers
asked
Mar 19, 2018
by
anonymous

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

What is the function of a thyristor?
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93 views
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
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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
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Last Answer : No we cannot turn off normal thyristor using Gate.
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1 answer
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Sep 21, 2017
by
anonymous
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Last Answer : Thyristor conducts when the anode voltage is greater than cathode and when the current provided to Gate.
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97 views
1 answer
asked
Sep 21, 2017
by
anonymous

Thyristor Switched Capacitor (TSC)
Last Answer : Thyristor Switched Capacitor (TSC) TSC is a static compensator. TSC is use for compensating reactive power. Compensation is required for voltage regulation, increasing stability, ... compensating device like TCS phase angle between voltage and current can be maintain.
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203 views
1 answer
asked
Aug 9, 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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1.7k views
1 answer
asked
Aug 8, 2017
by
anonymous

Thyristor controlled phase angle regulator
Last Answer : Thyristor controlled phase angle regulator
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196 views
1 answer
asked
Oct 12, 2017
by
pavan

what is TCSC?
Last Answer : Thyristor Controlled Series Capacitor (TCSC)
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224 views
1 answer
asked
Aug 8, 2017
by
anonymous
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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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3 views
1 answer

60 views
0 answers
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Apr 1, 2020
by
anonymous

46 views
0 answers
asked
Mar 27, 2020
by
anonymous

What is the difference between SCR and thyristor?
Last Answer : SCR is a type of thyristor. Like GTO, IGCT, MCT, TRIAC, DIAC etc. are the types of thyristor.
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2.7k views
2 answers
asked
Jul 6, 2019
by
anonymous

111 views
0 answers
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Dec 20, 2018
by
anonymous

72 views
0 answers
asked
Sep 21, 2018
by
anonymous

The turn-off time of a thyristor is 30 is at 50°C. What is its turn-off time at 100°C ?
Last Answer : The turn-off time of a thyristor is 30 is at 50°C. What is its turn-off time at 100°C ? 60 microsecond
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126 views
1 answer
asked
Apr 25, 2018
by
anonymous

During forward blocking state, a thyristor is associated with . (A) Large current and low voltage (B) Low current and large voltage (C) Medium current and large voltage (D) None of the above
Last Answer : A
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1.3k views
1 answer
asked
Apr 14, 2018
by
anonymous
