EE MCQ

MGVCL Exam Paper (30-07-2021 Shift 1)
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A fully controlled natural commutated 3-phase bridge rectifier is operating with a firing angle α = 30°, The peak to peak voltage ripple expressed as a ratio of the peak output dc voltage at the output of the converter bridge is

Where,

φ is firing angle

Voltage ripple for 3-phase bridge rectifier = cos(φ) = Cos(30)

= 1/2

Related Question

MGVCL Exam Paper (30-07-2021 Shift 1)
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Three resistances 750 Ω, 600 Ω and 200 Ω are connected in parallel. The total current is 1 A. Determine the voltage applied.

Equivalent resistance of the circuit, Req = (750|| 600 || 200)

Req = 125 Ω

Current from source = 1 A

Source voltage = 1*125

Source voltage = 125 V

MGVCL Exam Paper (30-07-2021 Shift 1)
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Determine maximum permissible load which a 15 MVA, ONAN cooled transformer to IS : 2026 can take for 6 hr, if the initial load on it was 12 MVA. The weighted ambient temperature is 20˚C. Assume the permissible load kVA as a fraction of rated kVA is 1.25.

Maximum permissible load = Rated MVA rating*fraction of rated kVA

Maximum permissible load = 15*1.25

Maximum permissible load = 18.75 MVA

MGVCL Exam Paper (30-07-2021 Shift 1)
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An RLC series circuit consists of R = 16 Ω, L = 5 mH and C = 2 μF. Calculate the quality factor.

For series RLC circuit,

Q = (1/R)*√(L/C)

Q = 1/16*√(5 mH/2 μF)

Q = 50/16

Q = 3.125

MGVCL Exam Paper (30-07-2021 Shift 1)
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A given solar cell has the following specifications: Isc = 4 A and Voc = 0.7 V. Consider that 20 identical cells with the above specifications are to be interconnected to create a PV module. What is the open-circuit voltage of the PV module if all the solar cells are connected in a series configuration?

For M no. of series configuration of solar cell,

Open circuit voltage of PV module= M*Voc

= 20*0.7

= 14 V

Short circuit current of PV module = M*Isc

= 20*4

= 80 A