Part B: If the load Speed-Torque characteristics (including the mechanical losses) is described by following equation: TL- |11.1+(5/150) Nrj. as shown in Fig.1. Determine the speed control range(maximum range) for three of the following cases: a- Reducing the stator voltage using autotransformer. b- Inserting external rotor resistance. c- Reducing the input voltage by 35%. d- Reducing the input voltage so that Vaew-0.85 V. Speed-Torque curve Shat spee pm N'anbe

Part B: If the load Speed-Torque characteristics (including the mechanical losses) is described by following equation: TL- |11.1+(5/150) Nrj. as shown in Fig.1. Determine the speed control range(maximum range) for three of the following cases: a- Reducing the stator voltage using autotransformer. b- Inserting external rotor resistance. c- Reducing the input voltage by 35%. d- Reducing the input voltage so that Vaew-0.85 V. Speed-Torque curve Shat spee pm N'anbe

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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Q.1: A series DC generator runs at 1000 rpm to supplies a current of 200A to the load at a voltage of 440V. The output power of the prime-mover 100kW, the resistances of the armature and series field are 0.05N and 0.152 respectively. A) Find at constant terminal voltage: (i) The load current for maximum efficiency, (ii) The maximum efficiency, B) If the speed changed to 1500 rpm, find the required divertor resistance which connected in parallel with the series windings to reduce the terminal 400V.
c) A 3 phase 6 pole star connected induction machine operates from a 120 V (phase voltage) and 50 Hz supply. Given the equivalent circuit parameters shown in Table Q4, and assuming the friction and windage loss is negligible, calculate the following parameters when operating at 1200 rpm: i. The slip (%). ii. The mechanical power (W). iii. The torque (Nm). iv. The efficiency (%). v. The no load current (A). d) Determine the following parameters for the motor in Q4c at start-up (zero speed): i. The motor phase current (A). ii. The power factor. iii. The input supply power (W). Parameter Value XM Units 85 Ω Re 250 250 R Xeg R Ω 200 Table Q4
A 240 V, compensated shunt motor driving a 1233.96 N.m torque load is running at 19.167 rps. The efficiency of the motor at this load is 94 percent. The combined armature, compensating winding and interpole resistance is 0.00707 ohm, and the resistance of the shunt field is 52.6 ohm. Determine the following parameters of the motor: (i) Input power (in kW) (ii) Field current (in Amp) (iii) Armature current (in Amp) (iv) Induced voltage in armature (in volts) (v) Torque developed by motor (in N.m) and (vi) The resistance of a dynamic breaking resistor (in ohm) that will be capable of developing 678 N.m of braking torque at a speed of 16.667 rps. Assume windage and friction at 16.667 rps is the same as at 19.167 rps. [Hint: 1 lb-ft = 1.356 N.m]"
1. a) Write the most common expressions that give the stored energy and induced electromagnetic torque of two windings within the mutual coupling. b) Give the induced electromagnetic torque expression of a switched reluctance machine having the winding current i, and winding self-inductance L1. c) What is the positioning of the armature and excitation field spaces in a DC machine? What is the advantage of this positioning for the researcher?
Give answer as soon as possible A 200 V dc shunt motor runs at no-load speed of 1000 rpm and takes line current of2 A. When it runs at rated load, the speed of the motor reduces to 920 rpm. Ifsupply voltage is constant, then calculate the line current drawn by the motor atrated load and mechanical power developed by the motor (neglect magnetic andstray load losses).
(c) Electric machines can be classified into two categories, state both categories. (d) Describe THREE (3) methods to control the speed of the DC motor. (e) State why induction (asynchronous) machines are not suitable to be used as a generators, (f) An induction machine is the most rugged machine and is widely used in domestic and industry. State its application in single phase and three phase systems.
Rotor current is about ................. A * Input current is ............. A * Speed at maximum torque is ............. r.p.m. * Starting torque is .................... N.m *
Q16 A 240V, 50 Hz, single-phase capacitor start a.c. motor is loaded such that the slip is 6% the motor constants referred to the stator are : Stator resistance 2.20; rotor resistance 3.80 Stator reactance = 30 ; rotor reactance 2.10 Magnetizing reactance 860 ; iron and friction loss 500 Draw the equivalent circuit and from it find the output power and efficiency at the given loading. Ans[ 1090 W, 74.6%]
coil of dc motor has armature resistance of 4.1N connected to voltage source of (220 V) and the coil develops a back e.m.f of (218 V) when rotating at normal speeds. Find the current when the motor first startup and the current when it is operating at normal speeds.
A 3-phase and 6-pole asynchronous motor is fed from a 100 Hz source. The engine speed under a certain load is up to 1940 rpm. If the load torque of the motor decreases by 20%, which of the following will the new speed of the motor be as given? (Note: You can think of the speed-torque relationship of the motor as linear in the steady operation region.) a.1979 rpm b.1976 rpm c.1952 rpm D.1967 rpm e.1928 rpm
pls answer soon
-A 250V, DC series motor has total resistance of 0.8 Q. Its full load current and speed are 10 A and 1500 r.p.m respectively. If the torque is reduced to 50% .Determine the current and speed. Assume straight line magnetization characteristics.