MCC - Motor Control Card
For large curtains with a longer ascent time, the link RL1 can be removed to increase the time that the MCC drives the motor. With the link in place, the timer drives for 45 seconds, with the link out this increases to 90 seconds. The green LED on the PCB illuminates to show when the motor is driving at full power. When the curtain has fully retracted the MCC ‘stalls’ the motor and the ‘fold back’ voltage of 3.5v holds the curtain up.