• The magnetic lines of force are directly responsible for magnetic field strength,
• The nearer to the magnet the stronger they become
• The strength of the field falls rapidly a small distance from the magnetic source.
• The unit of magnetic field strength is the Gauss ( pronounce like house).

Fig 4. Shows magnetic flow through the field poles and rotor of a four-pole motor.

The outer part of the stator to which the pole shoes are attached carries the same magnetic field as the pole shoes, which is why the iron in the motor stator needs to be extremely dense and heavy

Fig4