1-A d.c. shunt motor is running with certain load. The effect of adding an external resistance field circuit is to a)-reduce the motor speed, b)-increase the motor speed, c)- stop the motor d)- reduce the armature current of the motor 2- The copper loss and iron loss of transformer at half load are 1600 w and 5000w respectively. The copper loss and iron loss at full load will be respectively. a)-(3200 w and 10000w), b)- (6400 w and 5000 w), c)- (6400 w and 10000w), d)-(3200 w and 1250w) 3- The secondary winding of which of the following transformer is always kept close a)-power transformer d)-distribution transformer b)- auto-transformer, c)- current transformer,

1-A d.c. shunt motor is running with certain load. The effect of adding an external resistance field circuit is to a)-reduce the motor speed, b)-increase the motor speed, c)- stop the motor d)- reduce the armature current of the motor 2- The copper loss and iron loss of transformer at half load are 1600 w and 5000w respectively. The copper loss and iron loss at full load will be respectively. a)-(3200 w and 10000w), b)- (6400 w and 5000 w), c)- (6400 w and 10000w), d)-(3200 w and 1250w) 3- The secondary winding of which of the following transformer is always kept close a)-power transformer d)-distribution transformer b)- auto-transformer, c)- current transformer,

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

See similar textbooks

Similar questions

a) Which components determine the excitation current of a transformer? How are they in transformer equivalent circuit modeled? b) Why is the polarity determination of a transformer made? Briefly explain how the experiment is done. c) If the direction of rotation of the motor changes when the feeding ends are changed in a DC motor, what can be said about its type? d) Why does the peak voltage increase as the serial DC generator is loaded? How long does this increase continue?
a)Please explain the connection methods of Current and Voltage Transformers? b) Control the DC motor speed and direction. Draw the circuit.
1) total Armature Winding resistance of 60kW, 270V short shunt compound generator 54mΩ, series area windingits resistance is 40mΩ and the shunt field winding resistance is 135Ω. Brush-contact voltage drop is neglected.The generator supplies the load at Rated Power Rating (60kW) at rated voltage of 270V. Generatorthe voltage induced in the armature is 291V. (a) draw the equivalent circuit of the corresponding DC machine, specifying all current, voltage and winding resistors.Make appropriate current direction arrangements for the generator. (b) load current value (c) armature current value at full load
60kW, 270V short shunt compound generator total Armature Winding resistance 54mΩ, series area windingits resistance is 40mΩ and the shunt field winding resistance is 135Ω. Brush-contact voltage drop is neglected.The generator supplies the load at Rated Power Rating (60kW) at rated voltage of 270V. Generatorthe voltage induced in the armature is 291V. (a) draw the equivalent circuit of the corresponding DC machine, specifying all current, voltage and winding resistors.Make appropriate current direction arrangements for the generator. (b) load current value, (c) armature current value at full load (it is strongly requested that the articles you send be read)
18.a. A mechanical connection between machines is NOT needed for loading back tests ofA. induction machines.B. d-c series-wound machines.C. synchronous machines.D. d-c shunt-wound machines.18.b. The machine part which does not have any iron loss is theA. a-c motor stator.B. transformer core.C. d-c motor armature.D. alternator rotor.
A 220 V, single-phase induction motor gave the following test results:Blocked-rotor test: 120 V, 9.6 A, 460 WNo-load test: 220 V, 4.6 A, 125 WThe stator winding resistance is 1.5 Ω, and during the blocked-rotor test, the starting winding is open. Determine the equivalent circuit parameters. Also, find the core, friction and windage losses.
An 8-Pole, simplex lap wound, shunt generator has 800conductors and a flux per pole of 0.025Wb and running at 1200rpm. The armature and shunt field resistances are 0.25Ω and 120Ω respectively. If the armature voltage drop is equal to 10V, what is the load current (in Amp)? use two decimal places if the answer is not exact and do not include the unit anymore.
4. A 2 MVA, 2.3kV, three-phase Wye connected alternator operates at rated kVA at a power factor of 80 %. The dc armature winding resistance between terminals is 0.08-ohm. The field takes 70-A at 125-V from the exciter equipment. Friction and windage loss is 20-kW, iron loss 36-kW and stray power loss are 2.0-kW. Calculate the efficiency of the alternator. Assume the effective armature winding resistance is 120% of the dc resistance.
- Reconnecting Induction Motors 6.a. The voltage in a 460-volt motor is changed to 425 volts. If the original torque was 125 lb-ft, the newtorque isA. 135 lb-ft.B. 117 lb-ft.C. 115 lb-ft.D. 107 lb-ft.6.b. If a 575-volt three-phase motor originally connected in 3-parallel △ is reconnected in 5-parallel Y, thenew voltage isA. 501 volts.B. 794 volts.C. 598 volts.D. 747 volts.
The armature of a 400V, 6-pole, 25 Hz single-phase series motor is lap-wounded with 504 conductors Motor field winding has effective resistance and leakage reactionance are 0.06 22 and 0.05 12, respectively and has 18 turns. However, the armature winding has a leakage reactance of 0.04 12 and negligible resistance. At rated motor current of 300A, the flux per pole is 0.05 Wb, the short circuit current is 50A and the equivalent current to iron losses is 40A. Find motor speed , torque and efficiency at rated current .
1.5 A 10‐pole, 380 ‐V, 50 Hz, D‐connected three‐phase induction motor is rotating a quarry belt conveyor. The machine has the following parameters, referred to the stator, on a per phase basis: Stator Parameters Winding Resistance................0.19 Ω ......... Winding Reactance.................1.12 Ω.......... Rotor Parameters Winding Resistance......................0.29 Ω Winding Reactance.....................1.12 Ω Magnetising Reactance................................16.8 Ω Equivalent Core‐loss Resistance....................900 Ω. The friction and windage losses are 320 W. When the motor runs at its rated slip of 2.6 %. Determine: 1.5.1 The stator current. 1.5.2 Estimate the Output torque of the motor under the rated conditions. 1.5.3 The Motor…
A 240V shunt motor, running on no-load and at normal speed, takes an armature current of 2.4 A froma 240Vsupply. The resistance of the field circuit is 240Ω, and that of the armature is 0.25Ω. Calculatethe motor output power and efficiency when drawing a line current of 35 A from the supply