When the armature current of 5 Amp is flowing through the dc motor the torque produced is 47 Nm.
Keeping the speed constant if the armature current is increased to 7 amp, calculate the new torque.
Assume losses to be constant.
A. 27.73 Nm .
B. 38.5 Nm.
C. 65.8 Nm.
D. 74 Nm.
Answer: C
Share your understanding of this question with the correct explanation.
To calculate the new torque, we can use the relationship between torque and armature current in a DC motor. The torque is directly proportional to the armature current.
Given:
Initial armature current (I1) = 5 Amp
Initial torque (T1) = 47 Nm
New armature current (I2) = 7 Amp
New torque (T2) = ?
We can set up a proportion:
T1 / I1 = T2 / I2
Substituting the given values:
47 Nm / 5 Amp = T2 / 7 Amp
Cross-multiplying and solving for T2:
T2 = (47 Nm / 5 Amp) * 7 Amp
T2 = 329 Nm / 5
T2 = 65.8 Nm
Therefore, the new torque when the armature current is increased to 7 Amp is 65.8 Nm. The correct answer is C.