Question

Subject: Electrical Machines A dc series motor when running at 800 rpm draws a current of 100 amps from a source of 230 volts. The series field resistance Rs and the armature resistance Ra are 0.1 ohm and 0.15 ohm respectively. Calculate the torque developed. When the load is reduced the motor draws a line current of 70 amps. Assuming flux to be directly proportional to the current , find the resulting speed and torque.

Name: subject electrical machines a dc series motor when running at 800 rpm draws a current of 100 amps from a source of 230 volts the series field resistance rs and the armature resistance ra are 16308
Uploaded: 2023-09-17T12:04:46-08:00
Duration: 2 min 20 s
Channel: Adi S
Description: subject electrical machines a dc series motor when running at 800 rpm draws a current of 100 amps from a source of 230 volts the series field resistance rs and the armature resistance ra are 16308

          Subject: Electrical Machines
A dc series motor when running at 800 rpm draws a current of 100
amps from a source of 230 volts. The series field resistance
Rs and the armature resistance Ra are
0.1 ohm and 0.15 ohm respectively. Calculate the torque
developed.
When the load is reduced the motor draws a line current of 70
amps. Assuming flux to be directly proportional to the current ,
find the resulting speed and torque.

Added by Steve J.

University Physics with Modern Physics

Hugh D. Young 14th Edition

Instant Answer

Solved by Expert Adi S

09/17/2023

Step 1

We can use the formula for the torque of a DC motor: T = (Ia * Eb) / (ωm) where T is the torque, Ia is the armature current, Eb is the back EMF, and ωm is the angular velocity. First, we need to calculate the back EMF: Eb = V - Ia * Ra where V is the source Show more…

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Subject: Electrical Machines A dc series motor when running at 800 rpm draws a current of 100 amps from a source of 230 volts. The series field resistance Rs and the armature resistance Ra are 0.1 ohm and 0.15 ohm respectively. Calculate the torque developed. When the load is reduced the motor draws a line current of 70 amps. Assuming flux to be directly proportional to the current , find the resulting speed and torque.