A single-phase rotary converter has an output voltage of \(110\) volts. Determine the line current in the AC side when the machine delivers a DC output of \(50\) A. Assume the machine is operating with a pf of \(0.85\) and efficiency of \(95\%\).
A70.71 A
B90.34 A
C87.57 A
D82.23 A
#2📘 1001 RojasMedium
A three-phase rotary converter delivers \(150\) A at \(500\) VDC. Determine the current on the AC side if the operating power factor of the machine is \(0.8\) and the efficiency is \(90\%\).
A179 A
B157 A
C189 A
D196 A
#3📘 1001 RojasMedium
A 4-pole \(230\)-V, \(60\) Hz, three-phase induction motor directly drives a 6-pole alternator. Determine the output frequency. Assume a slip of \(3\%\) in the motor.
A90.0 Hz
B88.4 Hz
C86.6 Hz
D87.3 Hz
#4📘 1001 RojasMedium
A 4-pole, three-phase synchronous motor connected across a \(60\) Hz supply drives a 6-pole alternator through a belt. If the diameter of the driver and driven pulleys are \(6\) and \(10\) inches respectively, determine the operating frequency of the alternator.
A53 Hz
B54 Hz
C55 Hz
D52 Hz
#5📜 EE Board April 1992📘 1001 RojasMedium
A generator is rated \(600\) kVA, \(240\) V, \(60\) cycles, 3-phase, 6-poles and wye-connected. What will be the speed of the driving pulley if the driven and driving pulleys are \(1\) ft and \(2\) ft in diameter respectively?
A2400 rpm
B1200 rpm
C600 rpm
D900 rpm
#6📘 1001 RojasMedium
A \(230\)-V, 3-phase motor belt drives a \(50\) kW, \(250\) V DC generator. The motor, belt and generator efficiencies are \(0.91\), \(0.95\) and \(0.86\) respectively. If the motor operates at a pf of \(0.866\) lagging, determine the current drawn.
A189 A
B195 A
C192 A
DNone of these
#7📘 1001 RojasMedium
A single-phase motor is connected across a \(230\)-V, \(60\) Hz supply and draws \(30\) A at \(0.85\) pf lagging. This motor drives a \(120\)-V DC generator through direct coupling. If the motor, coupling and generator efficiencies are \(0.85\), \(0.96\) and \(0.88\) respectively determine the current delivered by the generator using the above condition.
A35 A
B32 A
C38 A
D48 A
#8📘 1001 RojasMedium
A \(230\)-V, \(60\) Hz, 3-phase motor drives a \(25\) kW, \(250\) V DC generator through belt and pulley. The motor and generator efficiencies are \(0.90\) and \(0.88\), respectively. If the motor draws a line current of \(98\) A at \(0.85\) pf lagging, how much is the combined efficiency of the belt and pulley?
A95.12%
B96.04%
C95.33%
D94.81%
#9📘 1001 RojasMedium
A half-wave rectifier draws power from a power transformer at \(24\) volts and delivers \(200\) mA to a load. Determine power drawn by load.
A0.48 W
B1.25 W
C2.16 W
D2.05 W
#10📘 1001 RojasMedium
An AC ammeter is connected in series across the output of a full wave rectifier. This meter reads \(8\) A. If a moving coil ammeter is replaced instead of the AC ammeter, what will be its expected reading?
A8.0 A
B7.6 A
C7.2 A
D5.6 A
#11📜 EE Board April 1997📘 1001 RojasMedium
A resistor is connected across an AC supply of \(220\) volts. The power drawn is \(1{,}000\) watts. If a diode were connected in series with the resistor, what would be the power absorbed by the resistor?
A850 W
B250 W
C750 W
D500 W
#12📜 EE Board April 1997📘 1001 RojasMedium
A germanium diode, which has an offset voltage of \(0.2\) V and an incremental resistance of \(20\) ohms, is connected in series with a \(10{,}000\)-ohm resistor across a \(100\) V DC source. What is the current?
