# In a thyristor D.C. chopper, which type of commutation results in best performance ?

In a thyristor D.C. chopper, which type of commutation results in best performance ?

## 2 Answers

Voltage commutation results in best performance in thyristor D.C. chopper .

voltage commutation

## Related questions

Answer : Yes, we can use triac in the multi-quadrant chopper.

Description : 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

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

Description : Explain two-quadrant chopper.........

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.

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

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.

Answer : Thyristor commutation means turning off thyristor.

Description : For a class D commutation, answer the following: i) Explain the operation with circuit diagram. ii) Interpret with waveforms.

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.

Description : Class D commutation

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.

Description : Draw circuit diagram of Class B commutation.

Answer : Class B: Resonant Pulse Commutation:

Description : Differentiate between Natural and Forced commutation

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

Description : Explain auxiliary commutation with a neat diagram. Also draw its waveform.

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.

Description : Define commutation. Give the types of commutation.

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

Description : 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

Answer : An FET is a better chopper than a BJT because it has lower offset voltage

Description : Chopper controlled DC motor

Answer : Chopper controlled DC motor

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.

Description : 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

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

Description : Class A Load Commutation

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.

Description : Draw a neat circuit diagram of class F commutation

Answer : class F commutation

Description : Which of the following learner characteristics are likely to influence the effectiveness of teaching aids and evaluation systems to ensure positive results? (A) Learner's family background, age and ... . (D) Learner's maturity level, academic perfor mance level and motivational dispositions.

Answer : (D) Learner’s maturity level, academic perfor mance level and motivational dispositions.

Description : Which of the following is also called as voltage commutation?   (a) CLASS A (b) CLASS B (c) CLASS C (d) CLASS D

Answer : Which of the following is also called as voltage commutation?   (a) CLASS A (b) CLASS B (c) CLASS C (d) CLASS D

Description : When determining the most appropriate form of leadership, which of the following should be considered? (a) The manager (b) The group (c) The work environment (d) All the above [hint: Clearly there is ... , the group and the work environment. It is not enough to simply consider one of these aspects.]

Answer : (d) All the above

Description : 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

Description : 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)

Answer : Natural commutation means: reducing the current to zero and allowing time to recover thyristor junctions

Description : Which type of conflict-handling intention results in a person‟s withdrawing from conflict? (a) competing ; (b) avoiding ; (c) accommodating ; (d) compromising

Answer :  (b) avoiding ;

Description : For maximum efficiency in learning a given passage for one single production (for example a school play), it is best to have Options: A) Many relatively short practice periods ... before the performance is required D) Relatively long practice periods concentrated just before performance is required

Answer : D) Relatively long practice periods concentrated just before performance is required

Description : A series of progressive approximations to a successful performance best defines Options: A) Developmental Tasks B) Learning C) Maturation D) The Scientific Method

Answer : B) Learning

Description : In a thyristor, the magnitude of anode current will:

Answer : In a thyristor, the magnitude of anode current will: Not change with any variation in gate current

Description : The number of p-n junctions in a thyristor are  A)1 B) 2 C) 3 D) 4

Answer : The number of p-n junctions in a thyristor are  3

Description : Anode current in an thyristor is made up of   (A) electrons only (B) electrons or holes (C) electrons and holes (D) holes only

Answer : Anode current in an thyristor is made up of electrons and holes

Description : In a thyristor, holding current is   (a) More than latching current IL (b) Less than IL (c) Equal to IL (d) Very small

Answer : In a thyristor, holding current is Less than IL

Description : Leakage current flows through the thyristor in

Answer : Leakage current flows through the thyristor in Forward blocking mode and Reverse blocking mode.

Description : What is the use of a thyristor in a circuit?

Description : Is gate turn on mechanism of GTO is similar to conventional thyristor?

Answer : Yes gate turn on mechanism of GTO is similar to conventional thyristor.

Description : 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

Description : 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

Answer : A thyristor (SCR) turns off when the Thyristor current is below holding value

Description : 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

Answer : Turn-on of a thyristor (SCR) takes place when Anode to cathode voltage is positive and positive current pulse is applied to gate

Description : Thyristor can be protected from over voltages by using

Answer : Thyristor can be protected from over voltages by using Voltage clamping device

Description : What is a phase control thyristor?

Description : Why thyristor are not preferred for inverter?

Description : What is thyristor family?

Description : What is meant by firing angle of thyristor?

Answer : The point at which SCR is triggered is known as firings angle of thyristor.

Description : What is a reverse conducting thyristor?

Description : What is the function of a thyristor?

Description : Why SCR is called as thyristor?

Description : Is a SCR a thyristor?

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.

Description : How is a thyristor used to convert AC to DC?

Description : What is the application of thyristor?

Answer : Yes ,it is one of the main advantage using thristors as a  switch in DC  circuit ,it has a high current gain

Description : Explain thyristor gate drive circuit.

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.

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.

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