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What is load commutation?
it is a type of forced commutation technique of thyristor
What is the difference between current and voltage commutation?
Voltage commutation: This is possible in ac circuits...The thyristor gets turned off by reverse bias (negative half cycle) voltage applied across it. This is also called line commutation. Current Commutation: This is possible in dc circuits ...This type of commutation makes use of auxiliary circuit which contains inductor,capacitor,diode and even a thyristor(auxiliary). This is called Forced commutation.
What is commutation of a rectifier?
Commutation in a rectifier: Refers to the process of transfer of current from one device (diode or thyristor) to the other in a rectifier. The device from which the current is transferred is called the "out going device" and the device to which the current is transferred is called the "incoming device". The incoming device turns on at the beginning of commutation while the out going device turns off at the end of commutation.Commutation failure: Refers to the situation where the out going device fails to turn off at the end of commutation and continues to conduct current.
What is conduction angle in thyristor?
not a clue a A: It all depends on the thyristor. There are no calculation involved not until you look up the thyristor specifications and decide on the load of the thyristor then you may calculate or more likely choose.
What is the function of thyristor?
Thyristor is a kind fast acting switch. These are fully controlled switches
What is load commutation?
it is a type of forced commutation technique of thyristor
How do you commutate heumann's chopper?
a Heumann chopper is nothing but the Class D commutation of a thyristor.refer to the following link on class d commutationhttp://www.slideshare.net/prathikm/thyristor-commutation-techniques
What is commutation of thyristor?
the process of turning off of a thyrisror is known as commutation
What is a line commutation?
it is the natural commutation ...by making open circuit or short circuit on the thyristor to make it turn off.
What is the difference between current and voltage commutation?
Voltage commutation: This is possible in ac circuits...The thyristor gets turned off by reverse bias (negative half cycle) voltage applied across it. This is also called line commutation. Current Commutation: This is possible in dc circuits ...This type of commutation makes use of auxiliary circuit which contains inductor,capacitor,diode and even a thyristor(auxiliary). This is called Forced commutation.
What does forced commutation mean?
The term "Forced commutation" is used when a thyristor is turned off using external components. If a thyristor is used in a DC circuit, when first turned on, it will stay on until the current goes to zero. To turn off the thyristor it is possible to use a Forced commutation circuit. The circuit creates a reverse voltage over the thyristor (and a small reverse current) for a short time, but long enough to turn off the thyristor. A simple circuit consist of a precharged capacitor and a switch (e.g. another thyristor) parallel to the thyristor. When the switch is closed, the current is supplied by the capacitor for a short while. This cause a reversed voltage over the thyristor, and the thyristor is turned off.
What is line commutation?
i think i know this answer...line commutation is the commutation in single phase inverters/converters when there is current flow back to the source.. It can also refer to a method of turning of a semiconductor device known as a Thyristor or SCR, sometimes called natural commutation. In this method the current between the anode and cathode is interrupted or dropped to a point where the Thyristor can no longer maintain its latch or keep conducting, shutting the device off.
What has the author L J Berman written?
L. J. Berman has written: 'A classification of thyristor commutation circuits for static invertors'
What is commutation of a rectifier?
Commutation in a rectifier: Refers to the process of transfer of current from one device (diode or thyristor) to the other in a rectifier. The device from which the current is transferred is called the "out going device" and the device to which the current is transferred is called the "incoming device". The incoming device turns on at the beginning of commutation while the out going device turns off at the end of commutation.Commutation failure: Refers to the situation where the out going device fails to turn off at the end of commutation and continues to conduct current.
What are the types of commutation?
Two types of commutation process 1) Natural commutation 2) Forced commutation
How does the turn off circuit on a Class B type thyristor work?
The Class B type of commutation circuit uses an LC circuit in parallel with the thyristor. During initial power up, the capacitor C charges to the supply voltage (Edc) and the thyristor is OFF. The initial charging current of the LC branch flows thru the load. When the thyristor is fired, the supply DC voltage is applied across the load, and the voltage across the LC branch goes to almost zero (the forward drop of the thyristor). Then the LC circuit enters a resonant discharge with an angular frequency of the square root of the inverse of LC product. The LC resonant cycle supplies a peak forward current thru the thyristor of Edc times the square root of C/L. This peak current must exceed the load current in order to effect the turn-off of the thyristor during the second half of the discharge resonant cycle. This peak current is usually designed to be twice the load current. The thyristor is reversed biased (and turned OFF) during the first quarter cycle of this second half of the resonant cycle - thus allowing the supply to recharge the capacitor in the LC parallel branch. Then the cycle can repeat.
How commutation can be improve?
Generally there are two methods of improving Commutation :- 1.Resistance Commutation 2.Emf or Voltage Commutation The Commutation can also be improve by using interpoles and compensating windings.
