Problem 517: Two identical shunt generators running in parallel supply a total load current of 2500 A. Each machine has a field resistance of 50 ohms and an armature resistance of 0.01 ohm. The induced emfs generated are 230 and 235 volts, respectively. Calculate the common operating voltage of each machine.
A220 V
B222 V
C223 V
D218 V
#42📘 1001 RojasMedium
Problem 518: Three shunt generators operating in parallel supply a total load current of 2000 amperes. Each machine has a field resistance of 40 ohms and an armature resistance of 0.02 ohm. The emfs generated are 240, 242 and 245 volts respectively. Determine current delivered by each generator.
A550 A, 600 A, 850 A
B550 A, 650 A, 800 A
C500 A, 650 A, 850 A
D600 A, 600 A, 800 A
#43📘 1001 RojasHard
Problem 519: Two shunt generators running in parallel deliver a total current of 3,600 A. Each machine has a field resistance of 60 ohms and an armature resistance of 0.01 ohm. The emfs generated by each machine are 455 and 460 V, respectively. Calculate the kW share of each machine.
A652 kW, 1087 kW
B670 kW, 1069 kW
C641 kW, 1098 kW
D682 kW, 1057 kW
#44📘 1001 RojasMedium
Problem 520: A shunt generator and a battery are connected in parallel serving a 500 A busload. The generator has an external characteristics such that the terminal voltage drops uniformly from 460 volts on no load to 440 volts on rated load while delivering 125 A of current. The battery has an open circuit emf is 420 V and internal resistance of 0.01 ohm. What percentage of the load current does the battery deliver?
A53 %
B47 %
C64 %
D36 %
#45📘 1001 RojasMedium
Problem 521: A 50 kW, 220 V dc generator has a voltage regulation of 10%. It is connected in parallel with a battery of 115 cells, each with an emf of 2 V and internal resistance of 0.01 ohm. What current will the battery carry if by accident the load is trip-off from the bus.
A0 A
B8.02 A
C6.15 A
D7.20 A
#46📘 1001 RojasMedium
Problem 522: Two identical 600 kW, 230 V dc generators are operating in parallel and take equal shares of an 800 kW, 250 V busload. The voltage regulation of each machine is 5%. If one of the generators is accidentally tripped off from the line, what is the voltage of the remaining machine?
A250 V
B243 V
C245 V
D247 V
#47📘 1001 RojasMedium
Problem 523: Two 250 V DC generators are operating in parallel and taking equal shares of a 3000 A, 250 V bus load. Ratings: Generator 1 (2% reg, 500 kW), Generator 2 (4% reg, 400 kW). If the load drops to 2100 A, determine the new operating bus voltage.
A252 V
B256 V
C254 V
D253 V
#48📘 1001 RojasEasy
Problem 524: Two shunt generators are operating in parallel and taking equal shares of a 2400 A, 230 V bus load. Ratings: Generator 1 (3% reg, 500 kW, 250V), Generator 2 (4% reg, 600 kW, 250V). If an additional 600-A load is connected to the bus, determine the current delivered by each generator at this condition.
A1516 A, 1484 A
B1525 A, 1475 A
C1612 A, 1388 A
D1655 A, 1345 A
#49📜 EE Pre-Board August 2012📘 PowerhouseEasy
In a 4 pole, 35 slot, dc armature, 180 electrical degrees coil span will be obtained when coils occupy _ slots.
A1 and 10
B1 and 9
C2 and 11
D3 and 12
#50📜 EE Pre-Board August 2012📘 PowerhouseEasy
An 8 pole lap wound dc generator has 1000 conductors in its armature. The flux produced per pole is 20 mWb and emf generated is 400 v. What is the speed of the machine?
A1160 rpm
B1200 rpm
C1240 rpm
D1300 rpm
#51📜 EE Pre-Board March 2013📘 PowerhouseEasy
A dc shunt generator has an induced voltage of 220 V on open circuit. When the machine is on load the voltage is 200 V. Find the load current if the field resistance is 100 Ω and the armature resistance is 0.2 Ω.
A100 A
B102 A
C98 A
D96 A
#52📜 EE Pre-Board August 2013📘 PowerhouseEasy
An 8-pole lap wound dc generator has 1,000 armature conductors, flux of 20 mWb per pole and emf generated is 400 v. What is the speed of the machine?
A1,000 rpm
B1,800 rpm
C1,200 rpm
D1,500 rpm
#53📜 EE Pre-Board March 2014📘 PowerhouseMedium
A 120 V shunt motor has an armature resistance of 0.5 Ω and a field resistance of 60 Ω. At full load, the motor takes 10 A and the speed is 1,000 rpm. At what speed must this machine be driven as a generator to deliver 10 A to an external load at 120 V?
A1,158 rpm
B1,086 rpm
C1,262 rpm
D1,045 rpm
#54📜 EE Pre-Board March 2014📘 PowerhouseMedium
A 20kW, 200 v shunt generator is operated at rated load. If the driving engine is developing 30 bhp, determine the iron and friction losses. Armature resistance is 0.05 ohm and shunt field resistance is 50 ohms.
A1,340 W
B1,039 W
C954 W
D1,034 W
#55📜 EE Pre-Board August 2014📘 PowerhouseEasy
A dc machine has 8 poles and a rated current of 100A. How much current will flow in each conductor at rated condition if the armature is simplex lap wound?
A6.25A
B50A
C25A
D12.5A
#56📜 EE Pre-Board August 2014📘 PowerhouseEasy
A 4-pole lap-wound armature has 480 conductors and a flux per pole of 25mWb. What is the emf generated, when running at 600 rpm?
A240V
B120V
C60V
D30V
#57📜 EE Pre-Board March 2015📘 PowerhouseMedium
A 10 kW, 110 volts dc series generator has a 2 volts brush drop, an armature resistance \(R_a\) of 0.1 Ω and a series field resistance \(R_s\) of 0.05 Ω. Calculate the generated emf when delivering rated current at rated speed.
A110 v
B130.25 v
C115.56 v
D125.64 v
#58📜 EE Pre-Board March 2015📘 PowerhouseMedium
The field current of a 200 kW, 230 volts shunt generator is 8 A when running full-load at rated terminal voltage. If the combined brush and armature resistance is 0.03 Ω, solve for the electrical efficiency of the generator.
A88.9%
B85.7%
C93.5%
D81.7%
#59📜 EE Pre-Board August 2015📘 PowerhouseEasy
In a 12-Pole duplex lap wound dc armature, each conductor can carry a current of 50 amperes. If the total armature conductor is 600, what is the rated current of the armature?
A30,000 A
B1,200 A
C600 A
D2,500 A
#60📜 EE Pre-Board March 2016📘 PowerhouseEasy
A 4 pole dc generator has a total of 600 conductors in its lap wound armature. The flux per pole is \(10^{6}\) lines. Determine the generated emf if it is driven at 2400 rpm.
