and three fig1 2 and 3 when pressure drops to the set point of pressure switch ps5 fig4 and 5 68 its contacts will close the alternator coil fig4 64 will become energized and power will be applied through the closed contacts fig4 69 of the alternator and through the closed contacts of the hand off auto selector switch fig4 62 set in the auto position to the coil of magnetic motor starter m4 fig4 56 when the main contacts of m4 close pump number four will be placed into operation to supply additional water to the service with additional service demand the pressure in tank three fig5 67 will be reduced further when it reaches the set point of pressure switch ps6 fig4 and 5 77 its contacts will be closed to energize magnetic motor starter m5 fig4 57 through the closed contacts of hand off auto selector switch fig4 63 pumps two three four and five now operate simultaneously to supply system demands if pressure continues to be reduced pressure switch ps4 fig2 10 of the basic system will close its contacts at the set point and restart pump number one fig1 1 of the basic system pumps one through five will now operate simultaneously to supply maximum system design capacity to service needs and will remain in operation until service demand is reduced when service demand is reduced the pressure in the secondary tank fig1 5 and in tank number three fig5 67 will be increased pressure switches ps4 fig2 10.