In industrial processing operation there are cases where machineries should be started one after the another. One example of electrical control applied to machineries in a processing operation is the sequential control shown in figure below (A) and (B). The 3 motors; M1, M2 and M3 are drive mechanical machine. Motor M1 is first started. After a Pre-set time, Motor M2 is started automatically. Later, with another pre-set time, motor M3 is started. Control Operation The first stage of control operation is started by pressing the start push button switch shown in figure 16 (a). Contactor C, timer TR1, and pilot lamp A are energized. Contact C1 (13-14) will close to maintain contactor C, timer TR1, and pilot lamp A. Contacts C2 (1-2,3-4,5-6) will also closed to energize and operate the motor M1, see figure 16 (b). Likewise the instantaneous timer contact TR1 (1-3) will close to prepare the second stage of operation (A) Control circuit of 3 stages sequential Control. After the pre-set...