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1) A capacitive load in voltage source inverters generates a. Small current spikes and can be reduced by using an inductive filter b. Large current spikes and can be increased by using an inductive filter c. Small current spikes and can be increased by using an inductive filter d. Large current spikes and can be reduced by using an inductive filter
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2) The carrier which are commonly used in constant - frequency PWM is a. Sawtooth carrier b. Inverted sawtooth carrier c. Triangle carrier d. All of these
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3) Double edge modulation eliminates certain harmonics when the reference is a a. Sine wave b. Square wave c. Triangular wave d. Trapezoidal wave
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4) In a three phase voltage source inverters a. Only amplitude of voltage is controllable b. Only phase is controllable c. Both amplitude and phase is controllable d. Amplitude, phase and frequency of voltages should always be controllable
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5) In a 3 phase VSI out of eight valid states, the number of valid states that produce zero ac line voltages is/are a. One b. two c. Three d. Four
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6) In the operation and control of both naturally commutated and forced commutated SCR base converter, commutation plays an important role. The converters is / are a. AC - DC b. DC - DC c. DC - AC d. All of these
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7) In commutation PAC stands for a. Permanent angle converter b. Phase angle converter c. Phase angle commutation d. Phase and commutation
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8) Any electrical signal present in a circuit other than the desired signal is known as a. Noise b. Distortion c. Interference d. All of these
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9) The man made noise sources is / are a. Motors b. Switches, radio interferences c. Computers, digital electronics d. All of these
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10) Due to non sinusoidal waveform of the input current, the power factor of the rectifier is a. Negatively affected by firing angle b. Negatively affected by distortion of the input current c. Positively affected by both firing angle and distortion of the input current d. Both (a) and (b)
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11) In rectifiers, load current flow is a. Unidirectional b. Bidirectional c. Either (a) or (b) d. Non directional
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12) Advantages of HVDC transmission over AC system is / are a. Reversal of power can be controlled by firing angle b. Very good dynamic behavior c. They can link two AC system operating unsynchronized d. All of these
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13) In dual converters, a. Both rectifiers provides positive current to the load b. Both rectifiers provide negative current to the load c. One rectifiers provide positive current to the load and the other negative current d. One rectifier provide positive current to the source and the other negative current to the load
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14) In a phase controlled 3 phase ac voltage controller, the harmonic present is a. 2nd b. 3rd c. 5th d. 7th
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15) The maximum firing angle in the half wave controlled regulator is a. 180 degree b. 190 degree c. 200 degree d. 210 degree
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16) The on - state voltage drop of IGBT consists of a. Drop across the collector junction b. Drop across the drift region c. Drop across MOSFET portion d. All of these
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17) To detect an over - current fault condition, the most reliable method is to connect a a. Current sensor across IGBT b. Voltage sensor across IGBT c. Current sensor in series with IGBT d. Voltage sensor in series with IGBT
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18) The IGBT resulted in higher switching speed and lower energy losses. It can be used for a. Uninterruptible power supplies b. Induction heating system c. Constant voltage and frequency power supplies d. All of these
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19) An ideal diode is a. Unidirectional b. Bidirectional c. Fixed voltage polarity d. Only (a) and (c)
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20) Bidirectional semiconductor device is a. Diode b. BJT c. SCR d. TRIAC
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