Tapped Field Control for DC Series Motors:

Tapped field control for dc series motors is another method of increasing the speed by reducing the flux and it is accomplished by reducing the number of turns of the field winding through which the current flows.

In this method of speed control of dc series motors a number of tappings from the field winding are brought outside, as illustrated in Fig. 1.72(b).

A number of series field turns can be short circuited according to the requirement. When all field turns are in circuit, the motor runs at the lowest speed and speed increases with cutting out some of the series field turns. This method is usually employed in electric traction.