Of a shunt excited DC generator, Excitation winding internal resistance Rf = 2.5 0 Armature winding internal resistance Ra = 0.5 Q www A rheostat has been placed in the excitation circuit to keep the end voltage of the machine constant at Va = 30 V. Machine Voltage magnetization induced in the armature while operating at n = 1400 rpm at If = 7 A excitation current %3D It is determined as Ea = 37 V from its characteristic. According to this, a) With peak voltage Va = 30 V, excitation current If = 7 A, power supplied to the load when the speed n = 1400 rpm What is the resistance of the rheostat? b) Spindle revolutions are reduced to n = 1000 rpm. In this case Va = 30 V and Ea = 37 V constant What value should the rheostat be adjusted to keep it? Calculate the power given to the load in this new case. w w

Of a shunt excited DC generator, Excitation winding internal resistance Rf = 2.5 0 Armature winding internal resistance Ra = 0.5 Q www A rheostat has been placed in the excitation circuit to keep the end voltage of the machine constant at Va = 30 V. Machine Voltage magnetization induced in the armature while operating at n = 1400 rpm at If = 7 A excitation current %3D It is determined as Ea = 37 V from its characteristic. According to this, a) With peak voltage Va = 30 V, excitation current If = 7 A, power supplied to the load when the speed n = 1400 rpm What is the resistance of the rheostat? b) Spindle revolutions are reduced to n = 1000 rpm. In this case Va = 30 V and Ea = 37 V constant What value should the rheostat be adjusted to keep it? Calculate the power given to the load in this new case. w w

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...

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111/ The armature reaction of the DC generator reduces the generated EMF. Select one: True False
Q23) A shunt generator supplies a 20KW load at 200V through cables of resistance, R = 100mΩ. If the field winding resistance ,Rf=50Ω and the armature resistance, Ra=40mΩ, i) Estimate terminal voltage across the load. ii) Calculate the emf generated in the armature.
. When a self-excited compound DC generator supplies load, the terminal voltage is not the same as the generated emE Why? a) voltage drop across the armature resistance will reduce the voltage available at the load terminals b) where there is a series field, voltage drop across the series field resistance will reduce the voltage available at the load terminals c) both "a" and "b" d) neither "a" nor "b"
Of a shunt excited DC generator, Excitation winding internal resistance Rf = 2.5 Ω Armature winding internal resistance Ra = 0.5 Ω A rheostat has been placed in the excitation circuit to keep the machine's end voltage constant at Va = 30 V. Machine Voltage magnetization induced in the armature while operating at n = 1400 rpm at If = 7 A excitation current It is determined as Ea = 30 V from its characteristic. According to this, a) With peak voltage Va = 30 V, excitation current If = 7 A, power supplied to the load when the speed n = 1400 rpm What is the resistance of the rheostat? b) Spindle revolutions are reduced to n = 1000 rpm. In this case Va = 30 V and Ea = 37 V constant What value should the rheostat be adjusted to keep it? Calculate the power given to the load in this new case.
A DC shunt generator supplies a load of 27 kW at 210 V through the cables of resistance, R = 126 mΩ. If the field winding resistance, Rf = 62 Ω and the armature resistance, Ra = 35 mΩ, Determine (a) the terminal voltage, and (b) the E.m.f. generated in the armature. The terminal voltage is = The E.m.f generated in armature is =
The flux density distribution in the airgap of a 60Hz,4-pole, salient pole machine is sinusoidal, having an amplitude of 0.8 T. Calculate the instantaneous and rms values of the voltage induced in 1150-turn, If the axial length of the armature and its inner diameter are both 100 mm.
Draw DC. Shunt generator which gives a full load output (30 K Watt) at the main voltage source of 200 voltage. In addition, gives the armature and shunt field resistors (0.05Ω and 50Ω), having 1000 watt iron and fractional losses. Calculate the Electro Magnetic field (EMF), Efficiency and Copper Loss.
The armature winding resistance of a long shunt connected DC generator is 0.4ohm, the resistances of the shunt and serial field windings are 125 ohms and 0.1 ohms, respectively. While the generator supplies 8KW of power to the load it feeds, which is the voltage it produces since the output voltage is 250V?
An 8 pole DC shunt generator with wave winding has 4800 conductor with 20 turns and average per pole flux is 20 mwb and armature current and armature resistance is 20 A and 0.5 ohm respectively find? (i) Induced emf (ii) Terminal goltage
A 250 V shunt generator has a full load armature current of 40 A, under these conditions the losses are: FW = 200 watts, shunt field = 100 watts, core = 260 watts, brush contact = 120 watts, armature copper = 400 watts. For operation at maximum efficiency, when the constant losses are equal to those losses that vary as the square of the load, calculate the maximum efficiency.
The armature reaction of the DC generator increases the generated EMF. Select one: True False
A 500-V, wave-wound, 750 r.p.m. shunt generator supplies a load of 195 A. The armature has 720 conductors and shunt field resistance is 100 Ω. Find the demagnetising amp-turns/pole if brushes are advanced through 3 commutator segments at this load. Also, calculate the extra shunt field turns required to neutralize this demagnetisation.