301Service Manual – CS7000 301Scrub SystemFunctional DescriptionOverviewThe scrub system includes the scrub brushes, scrub brush motors, side squeegees, and the scrub deckactuator which lowers and raises the scrub deck.The scrub deck actuator lowers the scrub brushes any time the scrub system is enabled. The brush motorsswitch on when the drive pedal is moved from the neutral position. The operator can enable the scrub systemindependent of the solution and recovery systems to scrub without adding or picking up solution.Scrub Pressure ControlThe electric scrub deck actuator motor (M11) moves the scrub deck up and down to control the scrubpressure. The retract limit switch (proximity sensor) (S1) stops the upward deck movement at the uppertravel limit.The brush current sensor (B1) acts like an “amp clamp” around the brush motor wires to constantly measurethe total current draw of all three brush motors. This current reading is sent to the A1 Main MachineController on pin J7-27 Brush Current Sense. The A1 Main Machine Controller interprets this current valueand raises or lowers the scrub deck as follows:• If the brush motor current drops below the preset limits for the selected scrub pressure (1-3), the scrubdeck actuator will lower the scrub deck to increase the scrub pressure and current draw until the currentdraw is again within the correct range.• If the brush motor current rises above the preset limit for the selected scrub pressure, the scrub deckactuator will raise the scrub deck to decrease the scrub pressure and current draw until the current drawis again within the correct range.The scrub brush current monitoring and scrub deck actuator allow the machine to automatically compensatefor a variety of floor surfaces and scrubbing conditions while maintaining constant scrubbing pressure.If the scrub deck actuator is unable to maintain the combined brush motor current draw below 75 amps for25 seconds, or if there is a short circuit, the A1 Main Machine Controller will set an over-current fault code.
