In a 2-pulse bridge converter with freewheling diode,width of the diode current pulse is (α is firing angle)
A 3-pulse converter feeds an RLE load. The source has a definite inductance causingoverlap. The thyristors a reideal. It has an overlap angle μ of 20° at the minimum firing angle α. The current remains constant in the complete range of firing angles. The range of firing angles of the converter would be
A circuit shown in the given figure is a/an
An amplifier circuit has an overall current gain of – 100 and an input resistance of 10 kW with a load resistance of 1 kW. The overall voltage gain of the amplifier is_______ dB.
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Solution
If a generator of 250 MVA rating has an inertia constant of 6MJ/MVA, its inertia constant on 100 MVA base is________
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Solution
Inertia constant on 100 MVA base
= 6⁄100 × 250= 15 MJ/MVAA
An energy meter is designed to make 100 revolutions of the disc for 1 kWh of energy. It is connected to a load carrying 40 A at 230 V and 0.4 power factor for an hour. The number of revolutions made by the meter will be_________.
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Solution
Energy consumed in one hour
= 230 × 40 × 0.4 × \(\frac{1}{1000}\)=3.68 kWh
Number of revolutions made by the meter
= 3.68 × 100 = 368 rev
A voltage of 2.70 V is being measured by an analog indicating instrument having a scale range of 0 – 5.0 V. If the instrument reads 2.65 V, then absolute error in measurement is________.
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Solution
Absolute error actual value – measured value
= 2.70 – 2.65 = 0.50 V
The Nyquist plot of a system is shown below
The open-loop transfer function is
\(G(s)H(s)=\frac{4s+1}{s^{2}(s+1)(s+2)}\)The no. of poles of closed loop system in RHP are _______.
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Solution
The open-loop poles in RHP are P = 0. Nyquist pathen closed gives the point (–1 + j0). Taking clockwise encirclements as negative N = –2
N = P – Z, –2 = 0 –Z, Z = 2 which implies that two poles of closed-loop system are on RHP.
A single phase semiconductor operated from 240 V, 50 Hz, if resistive load of 100 W connected at DC terminal of the con-verter and the average output voltage is 25% of maximum possible output voltage calculate average load current
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Solution
A surge of 100 kV travelling in a line of natural impedance 600 Ω arrives at a junction with two lines of impedances 800 Ω and 200 Ω respectively. What is the value of surge voltage?
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Solution