Many electrical problems can be explained using the logic in these three rules:
1. When a conductor cuts or is cut by magnetic lines of force, a voltage is created in the conductor.
2. The voltage value increases as the speed of cutting lines of force increases. An example is the speed of a generator’s armature.
3. The voltage value increases with an increase in the number of lines of force.
Example: Increasing the excitation amperes in the shunt field of a DC generator, or the rotor windings of an AC alternator, will increase the voltage value.
The speed at which lines of force cut conductors can be very high when AC or DC is switched off. The arc ...