The O.C.C. of a d.c. generator driven at 800 rev/min is as follows : EMF Field current (A) 2 When run as a shunt generator at 400 r.p.m, Find : 1. Voltage to which the machine will excite with shunt field resistance equal to 350. 2. lowest possible speed at which an O.C. voltage of 220 V can be obtained. 220 310 372 424 |3 4 542 492 8 460 520 9.

The O.C.C. of a d.c. generator driven at 800 rev/min is as follows : EMF Field current (A) 2 When run as a shunt generator at 400 r.p.m, Find : 1. Voltage to which the machine will excite with shunt field resistance equal to 350. 2. lowest possible speed at which an O.C. voltage of 220 V can be obtained. 220 310 372 424 |3 4 542 492 8 460 520 9.

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 separately excited generator when running at 1249 rpm supplies 110 A at 173 V to a circuit of constant resistance. Armature circuit resistance is 0.26 ohm. Determine the terminal voltage when the speed is dropped to 923 rpm. Assume that the field current is unaltered. • 2 decimal places • No need unit Round your answer to 2 decimal places.
An 8 pole shunt generator has a lap connected armature with 640 conductors. The flux per pole is 50 mWb. If the generator supplies two hundred fifty 230V, 15W – LED lamps, the field and armature resistances are 230Ω and 0.05Ω, respectively, determine the speed in rpm of the generator. Hint: The lamps are connected in parallel
This question is about d.c. machinesa)Explain briefly why the terminal voltage of a d.c. machine is not equal to thegenerated or back emf except at no load when V = E.b)Hence, state the relationship between V, E, the armature current and resistance thatapplies at normal loads for a generator.c)A 250 V shunt motor has an armature resistance of 0.4 Ω and runs at a speed of 750 rev min –1 when taking a full load current of 25 A.i)Estimate the speed of the motor at no load when the armature current is 3 A, assuming that the flux per pole remains constant.ii)Derive the relationship between speed, emf, and flux.iii)Calculate the field current for a field resistance of 110 Ω, if the load torque remains constant;iv)calculate the new armature current if the speed is increased to 1000 rev min –1v)Hence, find the value of the additional resistance required in the field circuit to maintain this current d)If the field current of a shunt wound d.c. motor is halved, what effect will thishave on the…
A 250 V, compound generator has armature, series field and shunt felid resistance of 0.4 Q, 0.2 Q and 125 2 respectively. If this generator supply10 Kw ,at rated voltage. Ignore armature reaction and assuming a drop of 1 volt per brush. Find the induce e.m.f and the armature current when the machine is connected Short compound. 1 Add file
1. show complete solutions and choose from the choices
Q1. The following data refer to the O.C.C of a D.C separately excited generator at 1000 rpm. Field current in A 0.2 0.4 0.6 0.8 1 1.2 Amature voltage in V 5 75 100 145 178 195 204 The machine is now connected as a shunt generator with a total field resistance of 200 Sn and driven at 1000 rpm. Estimate graphically: (i) the voltage to which the generat or will build up at no load. (ii) the armature, field and load currents when the teminal voltage is found to be 150 V. Neglect the effect of armature reaction and brush drop and assume armature resistance Rato be 0.8 2. (iii) Finally estimate the steady state armature curent when the machine terminals are shorted.
State two reasons why a self-excited shunt dc generator may fail to build up a voltage. In each (both) case, briefly explain what can be done to correct the problem. Reason #1 Solution #1 Reason #2 Solution #2
A long shunt compound generator delivers 100 A at 250 V. The armature, shunt field and series field resistances are 0.02 Ohms, 50 Ohms and 0.05 Ohms respectively. If the Break Horse Power (BHP) or the power developed by the shaft torque of the driving engine is 40, determine the stray loss.
Q2/ The open circuit characteristic of seperataly excited de generator driven at 1000 rpm is as follows: Field current 1 2 3 4 56 5.5 6 6.5 E.M.F volt 50 60 80 100 120 150 160 170 For this generator find: 1- No load voltage for the total shunt field resistance of 10002. 2- The critical resistance at 1000 rpm 3- The open circuit curve at 800 rpm and therfrom the open circuit voltage for a field resistance of 8002 (35 mark)