Problem 483: The armature of a 4-pole, 128 slots shunt generator is lap wound with four conductors per slot. The flux per pole is 50 mWb. The armature and shunt field resistances are 0.04 ohm and 50 ohms respectively. Determine the speed of the machine when supplying 400 A at a terminal voltage of 250 V.
A615 rpm
B622 rpm
C634 rpm
D624 rpm
#2📘 1001 RojasHard
Problem 492: A shunt generator is connected to a load that draws 28.8 kW. \(R_a=0.04\,\Omega\) and \(R_{sh}=48\,\Omega\). If the power developed in the armature is 106.3% of the power delivered to the load. Determine the terminal voltage of the generator.
A238 V
B240 V
C234 V
D236 V
#3📘 1001 RojasHard
Problem 501: A 30 kW series generator has an efficiency of 88 percent when operating at rated load. If the stray power loss is 15% of the full load losses, calculate the maximum efficiency of the generator. Assume that the stray power loss is constant and the other losses vary as the square of the load.
A90.43%
B92.04%
C91.12%
D89.92%
#4📘 1001 RojasHard
Problem 506: A long shunt compound generator has the following parameters: Ra = 0.1 \(\Omega\), Rse = 0.05 \(\Omega\) and Rsh = 120 \(\Omega\). This machine supplies power a aggregate dc load of 10 kW. At this load the armature generates 246 volts. Determine the terminal voltage.
A251.55 V
B257.86 V
C253.82 V
D247.33 V
#5📘 1001 RojasHard
Problem 507: A compound generator is to be operated, as a flat-compounded long shunt compound generator. To obtain the same rated voltage at full load and at no load when operated as a shunt generator, it is necessary to increase the field current by 0.20 A. The shunt field winding has 1000 turns per pole, and the series field winding has 4 turns per pole. If the full load armature current of the compound generator is 95 A and the series field resistance is 0.025 ohm, calculate the diverter resistance required.
A0.068 \(\Omega\)
B0.042 \(\Omega\)
C0.028 \(\Omega\)
D0.034 \(\Omega\)
#6📘 1001 RojasHard
Problem 508: The armature, series field and shunt field resistances of a 125 kW, 250-V long shunt cumulative compound DC generator are 0.025 \(\Omega\), 0.01 \(\Omega\) and 30 \(\Omega\), respectively. If the stray power loss at rated load is 5 kW, determine the motor brake horsepower required to drive this machine. Assume a brush drop of 2 V and a stray load loss of 1% of the output.
A182.32 hp
B201.33 hp
C190.85 hp
D210.56 hp
#7📘 1001 RojasHard
Problem 512: A short shunt compound generator has the following has an armature, series field and shunt field resistances are 0.04 ohm, 0.03 ohm and 80 ohms respectively. The generator serves a 20 kW, 200 V load through a feeder with an equivalent resistance of 0.1 ohm. Solve for the power generated by the armature.
A23.84 kW
B21.30 kW
C22.29 kW
D21.92 kW
#8📜 EE Board April 1993📘 1001 RojasHard
Problem 515: Two shunt DC generators G1 and G2 are rated at 100 and 150 kW at 110 V respectively. Their external load characteristics may be considered as straight line. The drop in the terminal voltage from no-load to full-load is 10 volts for G1 and 20 volts for G2. Calculate the no-load voltages of these generators when they are operated in parallel to supply a load of 2000 A, which is divided between them in proportion to their ratings.
AG1 = 123.7 V, G2 = 133.7 V
BG1 = 123.7 V, G2 = 131.7 V
CG1 = 121.7 V, G2 = 133.7 V
DG1 = 121.7 V, G2 = 131.7 V
#9📘 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.
