Figure 22. Right-Hand Rule.

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weak magnetic field at the leading edge of the rotor starts to cut across the

conductor and the voltage increases. When the rotor reaches position (2), the

generated voltage has reached its maximum value as shown above the horizontal line

in the illustration. The maximum voltage occurs when the rotor poles are directly

under the conductor. It is in this position that the conductor is being cut by the

heaviest concentration of magnetic lines of force.

c. It should be noted in particular that the magnitude of the voltage

varies because the concentration of magnetic lines of force cutting across the loop

of wire varies. The voltage curve shown is not a result of a change in rotor

speed, because in the illustration the rotor is considered to be turning at a

constant speed.

d. By applying the Right-Hand Rule (fig 22) to position (2), it is seen

that the direction of current in the loop of wire will be out of the top end of the

conductor and into the bottom end. Thus, the top end of the conductor will be

positive and the bottom end negative. The voltage curve which is shown above the

horizontal line represents the positive voltage at the top end of the wire loop

which is generated as the rotor turns from position (1) to position (3). As the

rotor turns from position (2) to position (3), the voltage decreases until at

position (3) it again becomes zero.

Figure 22.

Right-Hand Rule.

When the

rotor turns from position (3) to position (4), note that

the N pole of the rotor is now passing under the top part of the wire loop and

the S pole under the bottom part. From the Right-Hand Rule the top end of the loop

of wire is now negative and the bottom end positive. The negative voltage at the

top end Of the loop is pictured in the illustration by

OS 010, 1-P11