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Q 1/30
Score 0
How many parallel paths are there in the triplex lap wound armature of a 4 pole, dc generator?
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Q 2/30
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A 4 pole, dc generator with duplex lap wound armature current of 5A per conductor. What is the total armature current in amperes?
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30 questions
Q.
How many parallel paths are there in the triplex lap wound armature of a 4 pole, dc generator?
1
30 sec
Q.
A 4 pole, dc generator with duplex lap wound armature current of 5A per conductor. What is the total armature current in amperes?
2
30 sec
Q.
A 4 pole, dc generator has 400 conductors in its simplex wave wound armature. With a flux of 0.02 Wb per pole, the voltage generated by the armature is 213.33 V. Find the generator speed in rpm.
3
30 sec
Q.
When a dc generator is ran at 1080 rpm, the generated emf is 207 V. Find the generated emf in volts if the speed increased to 1200 rpm while the flux is kept constant.
4
30 sec
Q.
The no load voltage of a 50-kW, 220 volts, shunt generator in the FEU laboratory is 232 volts and rated load voltage is 220 volts. The armature resistance including brushes is 0.026 ohms and the resistance of the shunt field resistance is 52 ohms. What is the induced electromagnetic force at rated load?
5
30 sec
Q.
A 230-volt shunt generator has an armature circuit resistance of 0.05 ohm and shunt field resistance of 57.5 ohms. When the generator operates at rated voltage, it has a total core and mechanical losses of 1880 W. At what load does the generator operate so as to achieve maximum efficiency?
6
30 sec
Q.
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 varies as the square of the load.
7
30 sec
Q.
Two dc shunt generators 1 and 2 are connected in parallel supplying 120 A to a common load. Generator 1 has no-load voltage of 450 V and full load voltage of 375 V at 80 A; while generator 2 has no-load voltage of 475 V and full load voltage of 375 V at 100 A. Assuming the external characteristic curves of both machines to be straight lines, find the current delivered by generator 2 in amperes.
8
30 sec
Q.
A 4400v, 60 HZ transformer has a core loss of 840 watts, of which 1/3 is eddy current loss. What is the core loss when the transformer is connected to a 4600 v, 50 HZ source?
9
30 sec
Q.
Two compound generators are operated in parallel. If generator A has a series field resistance of 0.0015 ohm and is adjusted to take 30% of the line load while generator B with a series field resistance of 0.001 ohm takes the remainder of the load, what is the current flow in the equalizer, when the load is 230-kW at 230-volts.
10
30 sec
Q.
A short shunt compound generator has an armature, series, and field resistances of 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.
11
30 sec
Q.
A dc shunt generator has an induced voltage of 220 volts on open circuit. When the machine is on load, the voltage is 200 volts. Find the load current if the field resistance is 100 ohms and armature resistance is 0.2 ohms
12
30 sec
Q.
A 20 kW, 200 V shunt generator is operated at rated load. If the driving engine is developing 30 hp, determine the iron and friction losses. Armature resistance is 0.05 ohms and shunt field resistance is 50 ohms.
13
30 sec
Q.
The hysteresis and eddy current losses of a DC machine running at 1000 rpm are 250 watts and 100 watts respectively. If the flux remains constant, at what speed will the total iron loss be halved?
14
30 sec
Q.
A compound generator is to be operated as a flat-compound long shunt generator. To obtain the same rated voltage at full load and at no load when operated as shunt generator, it is necessary to increase the field current by 0.20 A. The shunt field winding has 1000 turns/pole and the series field winding has 4 turns/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.
15
30 sec
Q.
A 120 volts dc motor draws 225 A from the supply at a distance of 350 m using two copper conductors of diameter 0.5 inch. Find the voltage of the supply.
16
30 sec
Q.
A motor is supplying 60 N-m of torque to its load. If the motor's shaft is turning at 1800 rpm, what is the mechanical power to the load in horsepower?
17
30 sec
Q.
A 400 V, 10 kW series motor drives a fan when running at 800 rpm. The motor draws 50 A from the supply. The resistance of the armature and series field are 0.2 ohm and 0.1 ohm respectively. Determine the electromagnetic torque developed by the motor.
On a full load a 500-volt series motor takes 100 amperes and runs at 840 rev/min. The armature resistance is 0.1 ohm and field resistance is 0.04 ohm. Find the speed when developing half of full load torque but with a 0.08 ohm diverted in parallel with the field winding. Assume flux is proportional to the field current.
20
30 sec
Q.
A shunt motor has a rated armature current of 50 A when connected to 200 V. The rated speed is 1000 rpm and the armature resistance is 0.1 ohm. Find the speed if the total torque is reduced to 70% of that at rated load and a 3 ohms resistance is inserted in series with the armature.
21
30 sec
Q.
A 120 volt shunt motor has an armature equivalent of 0.5 ohm 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 may be driven as a generator to deliver 10 A to an external load at 120 volts?
22
30 sec
Q.
The nameplate rating of a shunt motor is 150 hp, 600 volts, 205 A, and 1700 rpm. The resistance of the shunt field circuit is 240 ohms and the total armature circuit resistance is 0.15 ohms. Calculate the speed regulation of the motor.
23
30 sec
Q.
A 100 volts shunt motor is developing 6 hp while operating at an overall efficiency of 86%. The armature and shunt field resistances are 0.06 and 50 ohms respectively. Determine stray power losses.
24
30 sec
Q.
A 240 volts dc series motor develops a shaft torque of 200 N-m at 92% efficiency while running at 600 rpm. Calculate the motor current.
25
30 sec
Q.
The shaft power of a shunt motor is 7.8 hp. Its armature draws 50 A from 120 volts. The field winding draws 1.2 A. What is the efficiency of the motor?
A 120 volts dc shunt motor has an armature resistance of 0.2 ohm. If the full load armature current is 75 A, find the starting resistance needed to limit the armature starting current to 150% of the full load value. Assume brush contact of 2 volts.
28
30 sec
Q.
A 110-volts dc motor draws an armature current of 16 A. If the armature resistance is 0.25 ohm, compute for the back emf.
29
30 sec
Q.
A motor is supplying 60 N-m of torque to its load. If the motor's shaft is turning at 1800 rpm, what is the mechanical power to the load in horsepower.