Question

Chapter 21, Problem 43Partially correct answer. Your answer is partially correct. Try again.The 1400-turn coil in a dc motor has an area per turn of 1.1 × 10-2 m2. The design for the motor specifies that the magnitude of the maximum torque is 8.4 N·m when the coil is placed in a 0.18-T magnetic field. What is the current in the coil?

Answer 1

The current in the coil is determined as 3.03 A.

How to calculate the current in the coil?

The current in the coil is calculated by applying the following formula as shown below.

The formula for torque in DC motor is;

τ = NBAI

where;

• N is the number of turns
• B is the magnetic field
• A is the area of the coil
• I is the current in the coil

The current in the coil is calculated as follows;

I = τ / NBA

I = ( 8.4 ) / ( 1400 x 0.18 x 1.1 x 10⁻²)

I = 3.03 A

Thus, the current in the coil is determined as 3.03 A.

Answer 2

I = 3.028 A

Step-by-step explanation:

given,

Number of turns in the coil = N = 1400

Area of DC motor per turn = 1.1 × 10⁻² m²

Maximum torque in motor = 8.4 N.m

Magnetic field in the coil = 0.18 T

Current in the coil = ?

using formula for toque in the magnetic field

τ = N A B I

8.4 = 1400 x 1.1 × 10⁻² x 0.18 x I

`I = (8.4)/(2.774)`

I = 3.028 A

Current in the coil will be equal to I = 3.028 A