A 140 V, DC separately excited motor drives a constant-torque load at 1000 rpm speed.The armature and field resistances are 0.9 and 145 N, respectively. The motor draws a linecurrent of 9 A at the given load and the field voltage is 115 V. Answer the following questions.1- Calculate the resistance that should beadded Radd to the armature circuit toRadd -wwInreduce the speed by 90%.RaddΩ2- Calculate the efficiency of the motorwithout the added Radd N if theE.rotational losses is equal to 135.12 W.V, Rf%R3- Calculate the efficiency of the motorwith the added Radd N if the rotationallosses is equal to 135.12 W.%4- Calculate the resistance that must be added to the armature circuit to operate the motor atthe holding condition.Radd

hi there, as per the guidelines, we answer first 3 sub parts of a query, please post Q4 as a…

A 140 V, DC separately excited motor drives a constant-torque load at 1000 rpm speed. The armature and field resistances are 0.9 N and 145 N, respectively. The motor draws a lin current of 9 A at the given load and the field voltage is 115 V. Answer the following questio 1- Calculate the resistance that should be added Radd N to the armature circuit to Radd ww I reduce the speed by 90%. Radd 2- Calculate the efficiency of the motor without the added Radd N if the D. rotational losses is equal to 135.12 W. V. R. V

A 140 V, DC separately excited motor drives a constant-torque load at 1000 rpm speed. The armature and field resistances are 0.9 N and 145 N, respectively. The motor draws a lin current of 9 A at the given load and the field voltage is 115 V. Answer the following questio 1- Calculate the resistance that should be added Radd N to the armature circuit to Radd ww I reduce the speed by 90%. Radd 2- Calculate the efficiency of the motor without the added Radd N if the D. rotational losses is equal to 135.12 W. V. R. V

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

Related questions

Q: A dc generator has a field flux of 0.001 Wb and 4 poles. The machine operates with at shaft speed of…

Q: A- A d.c. series motor draws 22 A from a 240 V line while running at 840 rpm. It has an armature…

Q: hotors a) What power is developed by a motor that turns at 1200 rpm and has a torque of 3.0 N-m?

A: Referring to question, the given information are: Speed of motor (s)=1200rpm. Torque (Ts)=3.0N-m.

Q: An induction motor has a full load slip of 0.04. It's starting current 5 times its full load…

Q: A series motor runs at 700 rev/min when the voltage is 300 V and the current is 20 A. The armature…

A: Initial speed of motor N1=700 rpm. Initial terminal voltage V1=300 V. Armature current Ia=20 A.…

Q: A 220 V series motor takes 15 A and runs at 700 rpm. The armature resistance including the…

A: The solution is given below

Q: A 22 kW, 230 V Series DC motor runs at 750 rev/min at full load and draws 110 A from the supply. The…

Q: 6. The motion in DC motor can be increased by the following factors... (yc may choose more than one)…

Q: A 230 V dc series motor has an armature resistance of 0.2 ohm and field resistance of 0.1 ohm at…

A: Given, Supply voltage, V= 230 V Armature resistance, Ra= 0.2 ohm Field resistance, Rse= 0.1 ohm Line…

Q: A d.c. shunt motor is running with certain load. For constant torque, the effect of adding an…

A: As per the guidelines of Bartleby we supposed to answer 1st question only since the 2nd question is…

Q: A DO shunt generator delivers 45 A at a terminal voltage of 220 V. The armature and the shunt field…

A: Given values are - IL=45AVt=220VRa=0.01ohmRsh=44ohmStray losses=375W

Q: A series motor runs at 800 r/min when the voltage is 400 V and the current is 25 A. The armature…

A: Given :- N1 = 800 rpm V1 = 400 V N2 = 600 rpm If1 = Ia = 25A If2 = 1.1…

Q: The field windings of the series motor have a resistance of 120 ohms at 15-degree C. After running…

Q: A universal motor has armature circuit resistance of 15 ohm and inductance of 0.3H. On being…

Q: A 120 V shunt motor has an armature equivalent of 0.5 ohm and a field resistance of 60 ohm. At full…

A: Given data, Armature resistance Ra=0.5 Ω Field resistance Rf=60 Ω Terminal voltage V = 120 V Load…

Q: the relation between armature and field currents in a series connected DC motor is O It = If + la O…

Q: A 220 V DC series motor runs drawing a current of 30 A from the supply. Armature and field circuit…

A: It is given that:

Q: series motor runs at 800 rev/min when the voltage is 400V and the current is 25A. The armature…

Q: (7) The only parts suffers from eddy currents in AC motors: a- The stator. b- The rotor. c- The…

A: 7. Answer: The stator and rotor Explanation: The rotating magnetic field and induced voltage cause…

Q: A 230v DC series motor takes 30A when giving its rated output at 1400 rpm. It has a field resistance…

Q: A 250 V series motor has an armature resistance of 0.2 ohm and a series-field resistance of 0.18…

Q: 1. The operation of Commutator in DC Motor is O a) to convert dc to ac O b) to convert ac to dc O c)…

Q: Q- The armature resistance of a permanent magnet dc motor is 0.80. At no load, the motor draws 1.5 A…

Q: A 240 V d.c. series motor takes 40 A when giving its rated output at 1500 rpm. Its resistance is 0.3…

A: Given, Supply voltage, V= 240 V Armature resistance, Ra= 0.3 ohm Armature current, Ia= 40 A Speed in…

Q: A 220 V shunt motor has an armature resistance of 0.5 ohm and takes a current of 40 A on full-loads.…

A: The solution for given shunt motor can be achieved as follows.

Q: A dc shunt motor runs at 900 rpm from a 460 V supply when taking an armature current of 25 A.…

Q: 459. The current drawn by a 460 V dc motor of armature resistance 0.5 ohm and back emf 420 V in

A: Given a dc motor with, Input voltage, V = 460 V. Armature resistance, Ra = 0.5 ohm. Back emf, Eb =…

Q: A dc series motor has an armature resistance of 0.06 Q and series field resistance of 0.08 Q. The…

A: As two questions are different so iam solving only one question i.e 1st question. take ratio of back…

Q: A 3-phase 50 Hz I.M. has a rated torque = 16.7 N.M and maximum torque = 40.5 N.M. If its rated speed…

A: Induction machine is a singly excited machine in which rotating magnetic field is generated by input…

Q: The DC shunt generator with the terminal voltage 300 V, armature drop 8 V and the each brush drop 2…

Q: A240 V d.c. series motor takes 40 A when giving its rated output at 1500 r.p.m. its total resistance…

Q: A 120 V shunt generator running at 850 rpm has its armature and shunt field resistance of 0.15 ohm…

A: Need to find copper losses

Q: Reducing the supply voltage so that Vnew = Vold / V3 reduces the maximum torque of the motor so that…

A: Maximum torque or Tmax is in direct proportion with frequency. So we will use the below relation…

Q: 2. A 2-pole, 50 Hz induction motor supplies 15 kW to a load at a speed of 2950 rpm. a. What is the…

A: Given data P=2, f=50 Hz Pload=15 kW, Nr=2950 rpm To find out We have to determine the slip, induced…

Concept explainers

Speed control of motor

Speed control by DC motor-speed controller is required to realize variable speed drive. Whenever a motor drives a particular load, it is called drive, and variable speed drive refers to a load requiring variable speed. All this is obtained by a DC motor speed controller.

Question

A 140 V, DC separately excited motor drives a constant-torque load at 1000 rpm speed.
The armature and field resistances are 0.9 and 145 N, respectively. The motor draws a line
current of 9 A at the given load and the field voltage is 115 V. Answer the following questions.
1- Calculate the resistance that should be
added Radd to the armature circuit to
Radd -
ww
In
reduce the speed by 90%.
Radd
Ω
2- Calculate the efficiency of the motor
without the added Radd N if the
E.
rotational losses is equal to 135.12 W.
V, Rf
%
R
3- Calculate the efficiency of the motor
with the added Radd N if the rotational
losses is equal to 135.12 W.
%
4- Calculate the resistance that must be added to the armature circuit to operate the motor at
the holding condition.
Radd

Expert Solution

This question has been solved!

Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.

SEE SOLUTION Check out a sample Q&A here

Step 1

Step 2

Step 3

Step 4

Step 5

Step by step

Solved in 5 steps with 11 images

SEE SOLUTION Check out a sample Q&A here

Knowledge Booster

Learn more about

Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, electrical-engineering and related others by exploring similar questions and additional content below.

Similar questions

A 240 V shunt motor has an armature current of 15 A when running at 800 rpm against full-load torque. The armature resistance is 0.6 ohm. What resistance must be inserted in series with the armature to reduce the speed to 400 rpm at the same torque? What will be the speed if the load torque is halved with this resistance in the circuit? Assume the flux to remain constant throughout.
A 220 V DC series motor runs drawing a current of 30 A from the supply. Armature and field circuit resistances are 0.4 and 0.1 respectively. The load torque varies as the square of the speed. The flux in the motor may be taken as being proportional to the armature current. To reduce the speed of the motor by 50% the resistance in ohms that should be added in series with the armature is
It's urgent please solve quickly.
On full load a 500 V series motor takes 100 A and runs at 820 rpm. The armature and series field resistances are 0.1 and 0.04 ohm respectively. What will be its speed when developing half-full load torque and with a 0.08 ohm diverter connected across the series field winding. Assume flux is proportional to the field current.
step by step
2. A 2-pole, 50 Hz induction motor supplies 15 kW to a load at a speed of 2950 rpm. a. What is the motor's slip? b. What is the induced torque in the motor in N-m under these conditions? c. What will be the operating speed of the motor be if its torque is doubled? d. How much power will be supplied by the motor when the torque is doubled?
A 3-phase 50 Hz I.M. has a rated torque = 16.7 N.M and maximum torque = 40.5 N.M. If its rated speed = 910 R.P.M, the :speed at maximum torque will be %3D R.P.M 578.28O R.P.M 421.640 R.P.M 590.160 None O
NEED ASAP A 2-pole series motor runs at 707 rpm, when taking 100-A at 85-V with the coils in series. What would be the speed if the coils were connected in parallel the load torque remaining the same. Resistance of each coil is 0.03-ohm and the armature resistance of 0.04-ohm.
Developed torque??
Short shunt.
Reducing the supply voltage so that Vnew = Vold / V3 reduces the maximum torque of the motor so that Tmaxnew= ...Tmaxold . * .... ...
True or fulse