search
person
Explain the three phase 120 degree mode VSI.

1 Answer

Three phase 120 degree mode VSI:

In the 120-degree mode voltage source inverter, each thyristor conducts for 120 degree of a cycle. 120-degree mode VSI required six steps, each step of 60 degree duration for completing one cycle of output AC voltage. During each step, only two thyristors will conduct, one thyristor will conduct from the upper group and one thyristor will conduct from lower group.

image image

image

thumb_up_alt 0 like thumb_down_alt 0 dislike

Related questions

Description : What is Voltage Source Inverter (VSI) ?

Answer : Voltage Source Inverter (VSI)  Inverter is device which converts Direct Current (DC) to Alternating Current (AC). There are two types of inverters one is Voltage source inverter ... VSI consist of two load terminals and three phase VSI consist of three load terminals.

Description : Give the circuit analysis of current source inverter with resistive load. What are the main difference between voltage source inverter and current source inverter?

Answer : Current source inverter (CSI): In current source inverter, the output current is independent of load. The input current of current source inverter is constant. Current source converter converts DC input current to ... are connected in parallel. In CSI diodes are connected in series.

Description : A 3-phase voltage source inverter is operated in 180o conduction mode. Which one of the following statements is true ?  (A) Both pole-voltage and line-voltage will have 3rd harmonic components ... from 3rd harmonic (D) Both pole-voltage and line-voltage will be free from 3rd harmonic components

Answer : A 3-phase voltage source inverter is operated in 180o conduction mode. Which one of the following statements is true ?  (A) Both pole-voltage and line-voltage will have 3rd harmonic components ... from 3rd harmonic (D) Both pole-voltage and line-voltage will be free from 3rd harmonic components

Description : Explain three phase half wave controller or three phase unidirectional controller.

Answer : Three phase half wave controller or unidirectional controller:

Description : Explain Three Phase Bidirectional Delta Connected Controller.

Answer : Three Phase Bidirectional Delta Connected Controller:

Description : Explain three phase bridge inverter.

Answer : Three phase bridge inverter: Three phase bridge inverter converts DC voltage input to three-phase variable frequency variable voltage output. DC voltage source can be a DC source or output of the rectifier. ... in proper sequence. The switch may be thyristor or IGBT etc.

Description : Explain three phase full wave controller.

Answer : Three phase full wave controller: Three phase full wave controller is also called as the three-phase bidirectional controller. Let the load is star connected so at each phase there are antiparallel connected SCRs. ... conduct at the same time and the third phase will be open.

Description : A three-phase synchronous motor has a terminal voltage of 460 V and a terminal current of 120 A at a power factor of 0.95 lagging, synchronous reactance of 1.68 ohm and the field current is 47 A. The field to armature mutual ... _____________.      (a). 20mH   (b). 16mH   (c). 24mH   (d). 22mH

Answer : 22

Description : 1. By whom were the members of the Constituent Assembly elected? 2. How much does one degree of the circumference of the earth measure (approx.)? 3. Which was the dynasty that succeeded ... of High Court judges be reduced? 20. Which electromagnetic radiation is most prevalent in the atmosphere?

Answer : Answer : 1. By Provincial Assemblies 2. 111 km 3. Rashtrakutas 4. Convection 5. Agricultural farmers 6. Hamilton (Canada) 7. Decreases with height 8. Tanka 9. Cholera 10. 24 11. Efflorescence 12 ... 16. Plasma membrane 17. Cadiz (Spain) 18. Ramtanu Pande 19. During a Financial Emergency 20. Infrared

Description : An additional condition for parallel operation of three-phase transformers over single-phase transformers is that

Answer : An additional condition for parallel operation of three-phase transformers over single-phase transformers is that the transformers should belong to the same vector group

Description : three phase to single phase cycloconverter

Answer : three phase to single phase cycloconverter

Description : A differential amplifier has a differential gain of 20,000, CMRR : 80 dB. The common mode gain is given by

Answer : A differential amplifier has a differential gain of 20,000, CMRR : 80 dB. The common mode gain is given by 2

Description : The threshold voltage of an n- channel enhancement mode MOSFET is 0.5V when the device is biased at a gate voltage of 3V. Pinch off would be occurs at a drain voltage of (A) 1.5V (B) 2.5V (C) 3.5V (D) 4.5V

Answer : The threshold voltage of an n- channel enhancement mode MOSFET is 0.5V when the device is biased at a gate voltage of 3V. Pinch off would be occurs at a drain voltage of 2.5V

Description : An amplifier has a voltage gain of 120. To reduce distortion, 10% negative feedback is employed. The gain of the amplifier with feedback is  (1) 141 (2) 92.3 (3) 9.23 (4) 1.41

Answer : An amplifier has a voltage gain of 120. To reduce distortion, 10% negative feedback is employed. The gain of the amplifier with feedback is 9.23

Description : Explain the principle of ON-OFF control and phase control of AC voltage controller with suitable circuit and waveforms.

Answer : The integral cycle control (on-off control) and phase angle control are the two types of AC voltage controller. The principle of ON-OFF control: The on-off control is also called an integral cycle ... control. In phase control, the switch is on for some period of each cycle.  

Description : Which one of the following four secretions, is different from the remaining three in regard to its mode of transport from the source gland to the site of action? (1) Saliva (2) Sweat (3) Bile (4) Epinephrine

Answer : Bile

Description : A 3-phase voltage source inverter operates in 180° conduction mode with a star connected resistive load. If input dc voltage is 100 V, then the peak to peak output line voltage is :

Answer : A 3-phase voltage source inverter operates in 180° conduction mode with a star connected resistive load. If input dc voltage is 100 V, then the peak to peak output line voltage is : 200 V

Description : In a two -channel oscilloscope operating in x -y mode, two in -phase 50 Hz sinusoidal waveforms of equal amplitude are fed to the two channels. What will be the resultant pattern on the screen ? (a) An ellipse (b) A parabola (c) Straight line inclined at 45° with respect to x-axis (d) A circle

Answer : In a two -channel oscilloscope operating in x -y mode, two in -phase 50 Hz sinusoidal waveforms of equal amplitude are fed to the two channels. What will be the resultant pattern on the screen ? (a) An ellipse (b) A parabola (c) Straight line inclined at 45° with respect to x-axis (d) A circle

Description : A cistern is filled in 15 hours by three pipes P, Q and R. The pipe R is thrice as fast as Q and Q is thrice as fast as P. How much time will pipe P alone take to fill the tank? A) 120 hrs B) 195 hrs C) 135 hrs D) Cannot be determined 

Answer : B Suppose pipe P alone takes x hours to fill the tank. Then, pipes Q and R will take x/3 and x/9hours respectively to fill the tank. 1/x + 3/x + 9/x = 1/15 13/x = 1/15 => x = 195 hrs.

Description : A seller buys three types of apples at Rs 150, Rs 120, and Rs 110 per kg. He mixes them in the ratio of 5:6:7 by weight and sells them at a profit of 50%. At what price per kilogram does he sell the apples? 

Answer : suppose the seller purchases 5kg , 6kg 7 kg apples. then the price of the total apple (5*150)+(6*120)+(7*110)=750+720+770=2240 as the total apples weights 18kg and the dealer makes a profit of 50% the selling price of apples per kg= 1.5* 2240/ 18 = 3360/18=Rs. 186.66

Description : One sixth of half of three fourth of a number is 25.What will be 30% of that number? a) 800 b) 120 c) 340 d) 300

Answer : Answer: B (1/6) ×(1/2)×(3/4)× x = 25 x/16 =25 x = 25×16 x = 400 30 % of 400 = 30/100 ×400  = 12000/100  = 120

Description : Nesha scored 120 out of 150 in English, 120 out of 180 in mathematics and 160 out of 200 in Science. Find Nesha’s score as percentage: (i) in Mathematics (ii) in all the three subjects (on the whole). a) 66 2/3, 78 22/51 b) 71 23/5, 45 7/31 c) 54 13/33, 82 3/4 d) 60 3/4, 76 32/41 

Answer :  Answer: A (i) Percentage scored in Mathematics = 120/180 100  = 12000/180  =1200/18  = 66 2 /3 % (ii) Total maximum of all the three subjects = 150 + 160 + 200 = 510 and Total score in the ... percentage on the whole = (400/510 100)  = (40000/510)  = 4000/51  = 78 22/51 %

Description : Three lamps are connected in parallel across a 120 Volt source. If one lamp burns out, the remaining two will be: A. Glow dimmer B. Glow brighter C. Not light D. Glow with the same brightness as before

Answer : Glow with the same brightness as before 

Description : A two-phase generator is connected to two 90Ω load resistors. Each coil generates 120 V ac. The value of current flowing through the common neutral line will be: A. 1.33 A B. 1.88 A C. 2.66 A D. 1.77 A

Answer : A two-phase generator is connected to two 90Ω load resistors. Each coil generates 120 V ac. The value of current flowing through the common neutral line will be: 1.77 A

Description : The stator of a 3 phase, 10 pole induction motor possesses 120 slots. If a lap winding is used, calculate the coil pitch, if the coil width extends from slot 1 to slot 11.  (A) 72.12% (B) 83.30% (C) 12% (D) 42% 

Description : A single phase motor draws a current of 5 A from a 120 V, 60 Hz line. The power factor of the motor is 65%. Calculate the active power absorbed by the motor.  (A) 600 W (B) 390 W (C) 456 W (D) 650 W 

Description : Explain three phase system of soil.

Answer : As natural soil contains solid soil particles and water and air present in its voids such complex nature of soil sample is difficult to analyze its physical properties hence it is simplify and ... water. In case of partially saturated soil, both air and water are present in the voids.

Description : Explain soil as three phase system with labelled sketch.

Answer : Soil as three phase system: 1. As natural soil contains solid soil particles and water and air present in its voids such complex nature of soil sample is difficult to analyze its physical properties Hence it ... In case of partially saturated soil, both air and water are present in the voids. 

Description : Explain with the neat circuit diagram only the scott connection scheme for conversion of three phase supply to two phase supply. Name one application of the same.

Answer : Three-phase to Two-phase Transformation (Scott Connection of Transformers): Working: i) Scott connection can be used for three-phase to two-phase conversion using two single-phase transformers ... a 3-phase system with a two-phase system with the flow of power in either direction. 

Description : List different starting methods of three phase synchronous motor. Explain any one of them.

Answer : Different Starting Methods of Three Phase Synchronous Motor: As synchronous motor is not self starting, different methods of starting are as follows: 1) By using an Induction (Pony) motor 2) ... . The rotor gets pulled into synchronism and starts running at constant speed as a synchronous motor. 

Description : Explain with neat circuit diagrams the procedures to perform no load and blocked rotor tests on three phase induction motor.

Description : Explain the need and steps to conduct the reduced voltage running up test on the three phase induction motor.

Description : Explain the construction of three phase induction motor with neat diagram.

Answer : Construction of Three-phase Induction Motor: There are two main parts of the three phase induction motor:  i) Stator which is the stationary part  ii) Rotor which is the rotating ... slip-rings. In this rotor also the slots are not exactly parallel to the shaft but slightly skewed.

Description : Explain power relations in three phase circuit.

Description : A single phase fully controlled thyristor bridge ac -dc converter is operating at a firing angle of 25 degree and an overlap angle 10 degree with constant dc output current of 20A. The fundamental power factor (displacement factor) at input ac mains is : (A) 0.78 (B) 0.827 (C) 0.866 (0) 0.9

Description : Explain the classification of rock based on mode of origin.

Answer : Classification of rock based on mode of origin (genesis): Based on mode of origin, the rocks are classified in to three categories described below. 1. Igneous Rock: Igneous rocks are of ... sedimentary rocks as a result of the action of the earth movements, temperature changes and liquid pressure.

Description : Explain with neat sketch construction of PIN Diode. Draw its characteristics in reverse bias mode. 

Answer : Construction A PIN diode is made up of three semiconductor materials; two heavily doped P- and N- type material separated by an intrinsic (undoped) semiconductor (I) as shown in above figure ... . This advantage allows the PIN diode to process even weak signals.  Characteristics

Description : Explain application of conduction and convection mode of heat transfer in automobile.

Answer : Applications of conduction1. Fins provided on motor cycle engine 2. Electric fuse cut off 3. Electric heater 4. Carbonisation of coal 5. Melting of iron in blast furnace 6. Fission reactions in ... 5. Radiator - Puts warm air out at the top and draws in cooler air at the bottom.

Description : A 400 W carrier is amplitude modulated to a depth of 75%.Calculate the total power in AM wave. (i) Explain the types of noise in a communication system. (ii) Compare simplex and duplex mode of communication.

Answer : (i) Noise: Noise is any spurious or undesired disturbances that mask the received signal in a communication system. a) Atmospheric Noise: Atmospheric Noise is also known as static noise which is the ... remote control ExamplesWalkytalky,telephone,mobile,Radar, FAX,Pager 4

Description : Explain the following Energy conservation methods of electrical motor : (a) Rewinding of motors (b) Operating in star mode

Answer : Energy conservation methods of an electric motor:  (a) Rewinding of motors: i) During rewinding by preserving the original winding characteristics (material quality, design and structure). It is ... in the lines also reduces leading to lower copper losses in motor and decrease line losses.

Description : Draw single phase full wave mid-point converter for inductive load. Draw input and output waveforms for it. 

Answer : Circuit Diagram: Waveforms:

Description : State classification of Phase controlled rectifiers.

Answer : Classification of phase controlled rectifiers:

Description : Single-phase mid-point controlled rectifier with RL load

Answer : Single-phase mid-point controlled rectifier with RL load : The circuit configuration of single-phase midpoint controlled rectifier is shown in the figure. During positive half-cycle of ... some part of next positive half-cycle of voltage with reversed polarity can appear across load.

Description : Single-phase Midpoint controlled rectifier with Resistive load

Answer : Single-phase Midpoint controlled rectifier with Resistive load:  1) During positive half cycle of AC supply, a is positive with respect to b , this makes T1 forward biased and T2 is reverse ... voltage reverses the polarity and T2 is turned off. The operation is as shown in waveforms.

Description : Give the operation of single phase full wave bridge controlled converter with RL load with a neat diagram. Also draw its waveform.

Answer : Single phase fully control bridge converter with RL load: 1. During positive half cycle of input voltage, T1 and T2 are forward biased and during negative half cycle, T3 and T4 are forward biased. Therefore, T1-T2 ... cycle till the firing of next pair of SCRs as shown in the waveform.

Description : A single phase fully controlled bridge converter supplies a load drawing constant and ripple free load current, if the triggering angle is 30o, the input power factor will be  (A) 0.65 (B) 0.78 (C) 0.85 (D) 0.866

Answer : A single phase fully controlled bridge converter supplies a load drawing constant and ripple free load current, if the triggering angle is 30o, the input power factor will be 0.78

Description : In a single-phase full converter, the number of SCRs conducting during overlap is   (a) 1 (b) 2 (c) 3 (d) 4 

Answer : 4

Description : In a 3-phase half-wave rectifier, if per phase input is 200 V, then the average output voltage is   (a) 233.91 V (b) 116.95V (c) 202.56 V (d) 101.28V 

Answer : a

← Prev Question Next Question →
editAsk a Question
...