For a DC machine having P no of pair of ___

Electrical Engineering MCQ Electrical Machines MCQ
1

For a DC machine having P no of pair of pole pairs, Z no of conductors having length L of resistivity ρ and cross section S are arranged.

What is the armature resistance?

A. PZL/4S
B. PZL/ 4Sa
C. PZL/4Sa²
D. PZL/4Sp²

Show Answer

Answer: C

Share your understanding of this question with the correct explanation.

2

The armature resistance of a DC machine can be calculated using the formula:

R_a = (ρ * L) / (A_c)

Where:
R_a = Armature resistance
ρ = Resistivity of the conductor material
L = Length of the conductor
A_c = Cross-sectional area of the conductor

In the given options, we have:

A. PZL/4S
B. PZL/4Sa
C. PZL/4Sa²
D. PZL/4Sp²

Comparing the options with the formula, we can see that option C matches the correct formula.

Therefore, the armature resistance is given by:
R_a = PZL/4Sa²