A class is designing a d.c. motor. To achieve a greater turning effect, three suggestions are made.
1 Have a larger current in the coil of the motor.
2 Have a stronger magnet in the motor.
3 Put a larger number of turns on the coil.
Which suggestions will help to increase the turning effect?
1, 2 and 3
1 and 2 only
1 and 3 only
2 and 3 only
Fig. 8.1 shows a horizontal, flat coil in a magnetic field
Fig. 8.1
The coil is connected to a cell. The coil rotates.
State and explain what happens to the coil as it reaches the vertical position.
To operate as a motor, a split-ring commutator and brushes are added to the parts shown in Fig. 8.1.
Explain the effects of the split-ring commutator and the brushes on the action of the motor.
Fig. 8.1 shows the single turn coil of a simple direct current (d.c.) motor.
Fig. 8.1
The coil is replaced by an otherwise identical new coil with three turns and the same current in the coil.
State how the turning effect compares with the turning effect in (i).
A third coil is identical to the coil in (i) except that its resistance is three times greater. The potential difference (p.d.) across the coil is the same as the p.d. in (i).
State how the turning effect compares with the turning effect in (i).