7. The following table relates to the open-circuit curve of a shunt gen- erator running at 750 rev/min: 10 172 300 360 385 395 Generated voltage (V) Field current (A) 0 1 2 3 4 5 Determine the no-load terminal voltage if the field circuit resistance is 125 Q. If the speed is now halved, what is the resultant terminal voltage? At the reduced speed, what value of field circuit resistance will give a no-load terminal voltage of 175 V? (N.C.T.E.C., O.2)

7. The following table relates to the open-circuit curve of a shunt gen- erator running at 750 rev/min: 10 172 300 360 385 395 Generated voltage (V) Field current (A) 0 1 2 3 4 5 Determine the no-load terminal voltage if the field circuit resistance is 125 Q. If the speed is now halved, what is the resultant terminal voltage? At the reduced speed, what value of field circuit resistance will give a no-load terminal voltage of 175 V? (N.C.T.E.C., O.2)

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 415V squirrel cage induction motor develops a torque of 40NM. The torque developed by the motor if the supply voltage drops to 380V is
A 240 V, 50Hz single phase supply feeds a SP-FC-FWR. The rectifier is used to power the armature of a separately excited DC motor. The DC motor ratings are 220 V, 10 A (armature current), 940 rpm, Ra= 1.750. What is the no-load speed of the motor?
Q5:- Adjust a fire angle for a three-phase full-wave semi-controlled converter to feed the separately exciter DC motor to get a load torque that can be reached to 730 rpm. When the supply voltage of converter is 160 volts per-phase and the absorbed current through the armature 40A with resistance 0.2 a and a constant back emf 04v/rpm. Then find the maximum speed for motor assume the previous parameters values are a constant.
A single phase half controlled rectifier is used to control speed of a dc motor rated at 110V,700rpm. Rectifier is supplied with 230V,60Hz. If the Ra is 0.4 Ohm and La is 5 mH. If the motor voltage constant is 0.07V/rpm, armature current is 35A and the motor is working at rated speed. Finda) Back EMFb) Vdcc) Firing angle in degreesd) Power delivered to the motor
Q5- Adjust a fire angle for a three-phase full-wave semi-controlled converter to feed the separately exciter DC motor to get a load torque can be reached to 750 rpm. When the supply voltage of converter is 150 volts per-phase and the absorbed current through the armature 40A with resistance 0.2 a and a constant back emf 0.4v/rpm. Then find the maximum speed for motor assume the previous parameters values are a constant.
A250 V, dc shunt motar has an armeture resistance of 0.5 chmand a field resistance of 250 chm When driving a load of constant torque at 600 r.pm, the amature current is 20 A If it is desired to raise the speed from600 to 800 r.pm, what resistance should be inserted in the shunt field circut? Assume that the megnetic circut is unsaturated
power electronics and drives
what is the best switch for buck boost converter and why
For a 18600W 2400rpm DC motor, the following values are given: Ra = 0.089 2 (value at room temperature (250C)), La = 0.00144 H, KT = 0.85 Nm / A and KV = 0.851 V / (rad / s)), (In calculations Use the hot resistance values at 1000C.) (Take the rated field winding losses as Wf= 210W.) If the motor speed is reduced to 50% of the rated speed (1200rpm), find the inductive voltage, the induced current, the motor efficiency and the motor speed at no load to obtain the rated torque at this speed. (Field supply current will be considered constant). I A V V Eff % ONL rpm
From the phasor diagram in the figure, deduce a expression for the output power, as a function of the armature current, Ia, and angle γ . Draw the curve Power (P) versus current angle (γ), for different levels of excitement Ef. For this consider negligible mechanical losses.
A DC chopper controls the speed of PMDC motor. The motor has 0.52 armature resistance and 0.05H armature inductance. DC bus voltage is 300V. In a specific load condition, when the duty cycle is 0.5, the back EMF of the motor is 140V. The chopping frequency is 1kHz. a. Sketch the circuit b. Find the maximum and minimum values of the motor current. c. Calculate the power to the motor. d. Find the Fourier series expansion of the load (motor) voltage. e. Explain the motor behavior when duty cycle is decreased gradually. f. If a low-pass filter (LC filter) connected to the motor terminals, explain the operation of the circuit.
3. A factory's separately excited DC generator has an armature resistance of 0.252. The machine is driven at 1000 revolutions per minute giving the following data: E,[V] I[A] a) Plot the open circuit characteristic when the machine is driven at 1000 and at 1500 rev/min. b) If the machine is drive at 1500 rev/min and its field current is adjusted to 0.2 A, plot the output voltage (in the same axis with (a)) as the load current is varied from 0 to 40A. For a full load current of 40A, what is the voltage regulation? 5 28 75 112 132 150 0.1 0.3 0.5 0.7 0.9