Quiz 2

The field windings of the series motor have a resistance of 120 ohms at 15-degree C. After running for two hours, the resistances increase to 140 ohms. If the temperature coefficient of the windings at 0 degree C is 0.004, find the new windings of the temperature

the field windings of a series motor has a resistance of 120 ohms at 15° c. after running for 2 hours, the resistance has increases to 140 ohms. if the temperature coefficient of the windings at 0°C is 0.004, find the new temperature of the windings

The field windings of a series motor has a resistance of 180 ohms at 30 degree Celsius. After running for 5 hours, the resistance increases to 140 ohms. If the temperature coefficient of the windings at 0 degree Celsius is 0.004. Find the new temperature of the windings. *

The field circuit of a 125-volt dc generator has a resistance of 50 ohms and an inductance of 12.3 henrys. A discharge resistor of 144 ohms is connected directly across the field winding at the instant the main switch is opened. What voltage appears at the winding terminals at t = 0, and what is the initial rate of current change?

A) Although the magnetic field for each phase of a 3-phase induction motor is merely switching back and forth between north and south poles, the resultant magnetic influence from all phases sets up a rotating magnetic field to cut the rotor conductors. a) true b) false B) In a two-pole stator winding of a 3-phase motor, how many revolutions does the rotating magnetic field make in one cycle of the electrical current? a) one b) 60 c) 3600 d) none of the above 3.

A DC shunt generator delivers 45 A at a terminal voltage of 220 V. The armature and the shunt field resistances are 0.01 2 and 44N respectively. The stray losses are 375 W. What is percentage efficiency of the DC generator

The field windings of a series motor has a resistance of 120 ohms at 15 ˚C. After running for two hours, the resistance increases to 140 ohms. If the temperature coefficient of the windings at 0 ˚C is 0.004, find the new temperature of the windings.

DEGREE: ELECTRICAL ENGINEERING  SUBJECT/COURSE: AC MACHINES   Answer the following questions (A, B and C) depending on the topic.   1. ALTERNATORS   A. Why is it necessary to maintain the speed of an alternator at all times and how do they control the speed of an alternator when in operation?   B. Distinguish between half-coiled and full-coiled armature windings in alternators.   C. Why are fractional pitch windings generally used in alternators?

A 240-V series motor has an armature resistanceof 0.42Ω  and a series-field resistance of0.18Ω . If the speed is 500 r/min when the current is36 A, what will be the motor speed when the loadreduces the line current to 21 A? (Assume a 3-Vbrush drop and that the flux is proportional to thecurrent.)

A wave wound armature of an eight-pole generator has 06 slots. Each slot contains 16 conductors. The voltage required to be generated is 300 V. What would be the speed of coupled prime mover if flux per pole is 0.05 Wb.If the armature is rewound as duplex lap wound machine and run by same prime mover, what will be the generated voltage.

Answer number 5 Make solution neatly and accurate

Armature windings in ac generators are same as those used in DC machines Select one: O True O False

Check the correct answer with some explanation please

Kindly solve what is ask with complete solution so that I can understand. I want a handwritten solution. Thank you very much pots!

At rated voltage, a 125 kw, 300-V long shunt compound system provides power with a stray power loss of 3.69 kW. The winding resistors are as follows: armature=0.023, series field=0.04, shunt field=75. Under this condition, find the efficiency of the system.

An alternator has 6 poles. (a) At what speed must the machine be driven to develop 60 cycles? 25 cycles? (b) What frequency is developed if the speed is 1000rpm?   Please give the complete solution for this problem. Thank you!

A) Although the magnetic field for each phase of a 3-phase induction motor is merely switching back and forth between north and south poles, the resultant magnetic influence from all phases sets up a rotating magnetic field to cut the rotor conductors. a) true b) false B) In a two-pole stator winding of a 3-phase motor, how many revolutions does the rotating tr) magnetic field make in one cycle of the electrical current? a) one b) 60   c) 3600 d) none of the above

Q choose the correct answer: 1-Brushless excitation system consisting of.... a- Stator field winding and power diodes b-stator and rotor field winding and capacitor c- stator and rotor field winding and capacitor d- Everything mentioned in the options 2- Voltage generated per phase in an alternator is proportional to a- Flux per pole b- Number of turns in armature c-Winding factors d- Everything mentioned in the options e- Frequency of waveform 3- If input mech. Power of SG constant, the functionality of AVR is a- Control flux of rotor b-Control terminal voltage c- Control flux and terminal voltage d-Control Load angle

The shunt field winding of a shunt generator has a resistance of 80 ohms at 20⁰C. After several hours of continuous operation, the winding temperature rises to 50⁰C. How much is the winding resistance under this condition, Assume the resistance temperature coefficient of copper to be 0.004 ohm per degree at 0⁰C.

The strength of the rotating magnetic field in a three phase induction motor is equal to times the flux produce ...... ....... in one of the phase windings. 1.25 1 O 1.5

solve this completly

A 4- pole series motor has 944 wave-connected armature conductors.At a certain load the flux per pole is 34.6 mWb and the total mechanical torque developed is 209 Nm.Calculate the line current taken by the motor and the speed at which it will run with an applied voltage of 500 V.Total motor resistance is 3N.

A long shunt compound generator supplies a load consists of 172 shunt lamps each rated at 48 W, 235 V. The resistance of the armature is 0.035 Q. The resistance of the shunt windings is 35 Q. The resistance of the series windings is ?0.014 Q. Find the efficiency. The stray loss is 583 W

5. Calculate the flux per pole required on full-load for a 50 kW, 400 V, 8-pole, 600 r.p.m. d.c. shunt generator with 256 conductors arranged in a lap-connected winding. The armature winding resistances is 0.1 Ω, the shunt field resistance is 200 Ω and there is a brush contact voltage drop of 1 V at each brush on full-load. Subject Electrical Machine 1

A dc shunt generator delivers 50 kw at 250 v, its armature has a 4-pole wave winding with a resistance of 0.01 ohm and its field resistance is 125 ohm. if the number of turns in the armature is 201 and the flux per pole is 0.02 wb, find the voltage generated and the speed of operation. *

A short shunt compound dc generator delivers a load current of 30 A and 200 V and has armature, series field and shunt field resistance of 0.05-ohm, 0.03 ohm and 200 ohms respectively. Calculate the generated voltage (allow 1 V for brush contact drop)

The DC shunt generator with the terminal voltage 300 V, armature drop 8 V and the each brush drop 4 v, then the value of generated emf is When the load on a series generator is decreased, then the flux produced will be decreased in direct proportion. Select one: O True O False