1. A two-pole DC generator has an armature containing a total of 40 conductors connected in two parallel paths.
The flux
per pole is 6.48 x 10^8 lines and the speed of the prime mover is 30 pm. The resistance of each conductor is 0.01 ohm
and the current carrying capacity of each conductor is 10 A. Calculate the terminal voltage of the generator
2. A four-pole shunt connected generator has a lap connected armature with 728 conductors. The flux per pole is 25
mWb. If the generator supplies two hundred fifty 110 V, 75 W incandescent lamp. The field and armature resistances are
110 ohms and 0.025 ohm respectively. Determine the speed in rpm of the generator.
3. A shunt generator is connected to a load that draws 28.8 kW. Ra = 0.04 ohms Rsh = 48 ohms. If the power developed
in the armature is 106.3% of the power deliver to the load. Determine the terminal voltage of the generator.
4. A shunt generator supplies 100 A at 200 V. The armature and shunt resistances are 0.025 ohms and 100 ohms,
respectively. If the copper losses are equal to the iron losses at this load, find the brake horsepower of the engine driving
the generator.
5. A compound dynamo supplies a load of 20 kW at 400 V through a feeder having a resistance equal to 0.1 ohm. The
shunt and series field resistances are 85 ohms and 0.06 ohm respectively. Determine the total electromotive force when
the generator is connected long shunt. Assume a brush contact drop of 1 V per brush and an armature resistance of 0.1
ohm.
6. A long shunt compound generator has the following parameters: Ra = 0.1 ohms, Rse = 0.05 ohms and Rsh = 120 ohms.
This machine supplies power a aggregate dc load of 10 kW. At this load the armature generates 246 volts. Determine the
terminal voltage.
7. A certain 5.5 kW, 125-V DC long shunt compound generator was operated as shunt motor at no load for determination
of stray power losses. With 135 V equal the generated emf at full load applied to the armature and at normal speed of
1700 rpm, the current input to the armature was found to be 2.5 A. The armature, shul field and series field resistances
are 0.2 ohms, 25 ohms and 0.25 ohms, respectively. Determine the efficiency of the generator at rated load.
8. A simplex lap wound armature has 580 conductors and carries a current of 125 amperes per armature current path. If
the flux per pole is 20 mWb. Calculate the electromagnetic torque developed by the armature?
9. A 220 V shunt motor driving its normal load draws an armature current of 50 A from a 220 V dc source. The armature
resistance of this motor including brushes is 0.25 ohm. How much armature current (minimum) will this motor draw
from a 200 V dc source when driving the same load with the field adjusted to maintain the same speed.
10. A DC shunt motor has a full load rating of 15 hp, 230 volts, 57.1 amperes, 1400 rpm. The armature circuit resistance
is 0.13 ohm and the field circuit resistance is 115 ohms. Neglecting the effect of armature reaction, determine the no-
load line current.
11. At rated load, a shunt motor draws an armature current of 50 A from a 230 V dc mains while running at 1000 pm. At
no load the armature current drops to 5 A. If the effect of armature reaction has weaken the flux by 2% from no-load to
full loan determine speed of the motor at no-load. Assume the armature resistance to be 0.15 ohm.
12. The nameplate rating of a shunt motor is 150 hp, 600 volts, 205 A, 1700 rpm. The resistance of the shunt field circuit
is 240 ohms and the total armature circuit resistance is 0.15 ohm. Calculate the speed regulation of the motor.
13. A 120-V shunt motor has an armature equivalent of 0.5 ohms and a field resistance of 60 ohms . At full load, the
motor takes 10 A and the speed is 1000 rpm. At what speed must this motor maybe driven as a generator to deliver 10 A
to an external load at 120 V?
14. The nameplate rating of a shunt motor is 150 hp, 600 volts, 205 A, 1700 rpm. The resistance of the shunt field circuit
is 240 ohms and the total armature circuit resistance is 0.15 ohm. If the motor is to be deliver full-load torque at 1,200
rpm, what value of resistance must be added to the armature circuit?
