What is mean by forced commutation of thyristor?

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Answer :

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

What is mean by natural commutation of thyristor?

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.

Differentiate between Natural and Forced commutation

Description : 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

what is thyristor commutation?

Last Answer : Thyristor commutation means turning off thyristor.

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

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

Last Answer : voltage commutation

Class A Load Commutation

Description : 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. 

In a 3-phase converter circuit during commutation when one SCR in one phase is turned on to turn-off an SCR

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

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

Define natural, mechanical, forced and induced draught systems.

Description : Define natural, mechanical, forced and induced draught systems.

Last Answer : Natural draught system: - When the fuel is burnt (combustion) in the furnace due to natural circulation of air, the draught is called natural draught. Mechanical draught system: -  In a mechanical ... combustion. OR If fan/blower is placed after the furnace then it is called as induced draught

can we turn off thyristor using Gate?

Last Answer : No we cannot turn off normal thyristor using Gate.

when a thyristor conducts?

Last Answer : Thyristor conducts when the anode voltage is greater than cathode and when the current provided to Gate.

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

Description : 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.

Draw circuit diagram of Class B commutation.

Description : Draw circuit diagram of Class B commutation.

Last Answer : Class B: Resonant Pulse Commutation:

Class D commutation

Description : 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.

Draw a neat circuit diagram of class F commutation

Description : Draw a neat circuit diagram of class F commutation

Last Answer : class F commutation

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

Description : 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.

Define commutation. Give the types of commutation.

Description : 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

Satisfactory commutation of D.C. machines requires?

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.

Describe the working principle of Thyristor operated dimmer with the help of circuit diagram.

Description : 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.

Thyristor can be protected from over voltages by using

Description : Thyristor can be protected from over voltages by using

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

Leakage current flows through the thyristor in

Description : Leakage current flows through the thyristor in

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

What is meant by firing angle of thyristor?

Description : What is meant by firing angle of thyristor?

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

Is a SCR a thyristor?

Description : 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.

How is a thyristor used to convert AC to DC?

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

Last Answer : thyristor

Is thyristor a DC switch?

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

Explain thyristor gate drive circuit.

Description : 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.

parallel operation of mosfet can be done more easily as compared to thyristor. why?

Description : 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.

what are the disadvantages of thyristor?

Description : 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

write short notes on thyristor CSI .

Description : 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.

thyristor have how many terminals?

Last Answer : Thyristor have three terminals anode, cathode and Gate.

thyristor can be turned off by?

Description : 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.

why thyristor is called semi controlled device?

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.

why thyristor is called latching device?

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.

Thyristor Switched Capacitor (TSC)

Description : 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.

what is gate turn off thyristor (GTO)?

Description : 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).

explain TCPAR & voltage regulator

Description : Thyristor controlled phase angle regulator

Last Answer : Thyristor controlled phase angle regulator

what is TCSC?

Description : what is TCSC?

Last Answer : Thyristor Controlled Series Capacitor (TCSC)

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

Description : 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

What is forced commutation?

Description : What is forced commutation?

Last Answer : The process of the current flowing through the thyristor is forced to become zero by external circuitry is called as forced commutation.

Which of the listed colors properly describes a DC motor commutator when correct commutation is taking place? A. Shiny blue B. Burnished green C. Brick red D. Chocolate brown

Description : Which of the listed colors properly describes a DC motor commutator when correct commutation is taking place? A. Shiny blue B. Burnished green C. Brick red D. Chocolate brown

Last Answer : Answer: D

Brush sparking during commutation may be caused by ________. A. eddy currents in the armature core B. laminations in the generator field pieces C. induced current opposite to coil inductance D. coil inductance discharge occurring at commutation

Description : Brush sparking during commutation may be caused by ________. A. eddy currents in the armature core B. laminations in the generator field pieces C. induced current opposite to coil inductance D. coil inductance discharge occurring at commutation

Last Answer : Answer: D

What is the function of the interpoles installed in DC motors? A. To provide greater torque by strengthening the main field. B. To provide sparkless commutation without having to shift the brushes. C. To limit the production of counter-electromotive force. D. To limit the starting surge current.

Description : What is the function of the interpoles installed in DC motors? A. To provide greater torque by strengthening the main field. B. To provide sparkless commutation without having to shift the brushes. C. To limit the production of counter-electromotive force. D. To limit the starting surge current.

Last Answer : Answer: B

How is the inverter circuit classified based on commutation circuitry?

Description : How is the inverter circuit classified based on commutation circuitry?

Last Answer : a. Line commutated inverters. b. Load commutated inverters. c. Self commutated inverters. d. Forced commutated inverters.

What is meant by load commutation?

Description : What is meant by load commutation?

Last Answer : In this process, the load current flowing through the thyristor either becomes zero or is transferred to another device from the conducting thyristor.

What is meant by current commutation?

Description : What is meant by current commutation?

Last Answer : In this process, a current pulse is made to flow in the reverse direction through the conducting thyristor and when the net thyristor current becomes zero, it is turned off.

What is meant by voltage commutation?

Description : What is meant by voltage commutation?

Last Answer : In this process, a charged capacitor momentarily reverse biases the conducting thyristor and turn it off.

What are the different types of chopper with respect to commutation process?

Description : 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.

What is commutation angle or overlap angle?

Description : What is commutation angle or overlap angle?

Last Answer : The commutation period when outgoing and incoming thyristors are conducting is known as overlap period. The angular period, when both devices share conduction is known as the commutation angle or overlap angle.

What are the types of commutation with respect to commutation process?

Description : What are the types of commutation with respect to commutation process?

Last Answer : Voltage commutated chopper Current commutated chopper Load commutated chopper

What is natural commutation?

Description : What is natural commutation?

Last Answer : The process of the current flowing through the thyristor goes through a natural zero and enable the thyristor to turn off is called as natural commutation.

What is meant by commutation?

Description : What is meant by commutation?

Last Answer : The process of changing the direction of current flow in a particular path of the circuit. It is used to turn off the SCR.

What is commutation?

Description : What is commutation?

Last Answer : Usually the width of the brush is equal to the two segments of the commutator. Whenever a brush contacts two or more commutator segments, the connected to those segments are short- ... the winding. The remedies for rough commutation are resistance commutation method and emf commutation method.