Two 10 W silicon photovoltaic modules (Sinopuren) were used to charge 12V/70 Ah battery needed to drive the DC motor, control components and a DC closed loop HT water pump. The PV modules shown in Figure 5 were fixed on the tracking frame to improve PV cell efficiency by minimising solar incident angle. Having this type of power supply, the system can operate independently and off the grid. The selection of the PV and the battery sizes were based on the
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power required by the control system and DC water pump. The required motor torque was estimated experimentally to be 100 Nm. Based on this torque, a 12 V motor unit of 0.75 RPM was found suitable for the tracking mechanism. A sprocket and chain system was used to connect the motor unit with the main tracking shaft as shown in Figure 5. The motor power consumed during system operation was measured to be 2.2 W.