Nilfisk-Advance 56314019, Service Manual

28 - FORM NO. 56043089 / AquaRide

™

 / BRX 700

SCRUB BRUSH SYSTEM

FUNCTIONAL OVERVIEW

•  Cylindrical Brush System Overview
See Figure 6.  The machines AquaRide SE and BRX 700 use two cylindrical brushes that counter rotate to sweep up light debris and scrub at the 
same time.  Each scrub brush is powered on opposing ends by 3/4 HP permanent magnet motors attached to separate poly-V belt/pulley drives.
•  General Brush Overview
On all models the scrub deck platform is raised & lowered automatically by a vertically mounted electric lift actuator motor (M1).  The operation of 
the machine’s scrub functions are activated when the operator selects (presses) either the scrub maintenance or restoration (mode) panel buttons.  
The scrub brush pressure ranges (light through heavy) are programmable allowing the operator the choice to vary the scrubbing effort (pressure) 
for numerous carpet cleaning requirements.  Note: See the Main Control Board Special Program Options section in this manual for more detailed 
operation and instructions to change scrub pressure settings.
See Figure 1.  The machine’s main scrub system input and output operating functions are regulated (managed) by the combined membrane switch 
display panel and main control board E1.  The major scrub system functions are…
•  Scrub Brush Motor Run Function
To turn On (energize) the K1 brush motor solenoid either the scrub pressure maintenance or restoration buttons (location E1 panel) must be pressed 
and the (foot activated) drive pedal moved off its neutral position triggering an output from the R1 directional throttle potentiometer.  These two-
operator functions deliver the required E1 control board and A1 speed control circuit inputs.
Detailed Explanation of the scrub motor function
A closed E1 membrane panel switch input (either maintenance or restoration) enables the E1 microprocessor automatic functions for the brush 
lift, brush solenoid, solution solenoid and vacuum solenoid.  The next step is the movement of the foot pedal for the needed R1 throttle output to 
the A1 speed controller, which causes either FWD or REV motor action.  At the moment of R1 throttle input the A1 controller closes an internal coil 
driver and outputs a POS. 36V signal from pin #6 (wire color Red/Blk) to the E1 J4-10 connection.  This positive input signal causes the controller 
to output a NEG. 36V signal from J2 pin #1 (wire Wht/Red) and completes the K1 negative solenoid coil pulling in the high current contactor making 
the brush motor(s) turn on (run).  Note: The positive K1 control circuit voltage is supplied by the E1 board’s J2 pin #8 wire (Wht/Brn).
•  Scrub Brush Actuator Lift Motor Function
The control board outputs activate (raise and lower) the scrub-deck for installing, removing and controlling the scrub brushes’ selected pressure 
limits (current load).  The negative (-) brush motor wire is specially designed so that it has a known (specifi ed) resistance value.  As brush motor 
current passes through the negative wire that is, in effect, a low value resistor, a small voltage drop is measured across it which is proportional to 
the motor current.  This current measurement shunt circuit is made up of two small diameter sense wires (J4-12 Yel/Vio & J4-8 Blk) and are the 
inputs used by the control board to calculate the exact current level of the scrub brush motor(s).  Any temperature change to the large (Neg.) motor 
wire affects its resistance so the circuit temperature is sensed by a thermistor (*) built into the control board.  This allows the controller to provide 
a level of error correction for the temperature resistance changes.  When the controller senses a current draw out of the desired range (selected 
pressure limit) it automatically turns on the M1 actuator motor to raise or lower the scrub deck.  This process is on-going in maintaining the operator’s 
selected scrub motor current load (setting #) to sustain the desired brush working pressure.
•  Low Voltage Cut-Out Function
The purpose of the low voltage cutout function is to help prolong battery life.  The main control board E1 is programmed to monitor the machine’s 
battery pack voltage to prevent over discharging of the batteries.  The brush motors, brush lift actuator and solution solenoid valve will turn OFF 
automatically and cease to function when the batteries are discharged to the selected cutout level.  The cutout level is adjustable between two 
settings.  The standard battery type (wet cell) is 31.5 volts (1.75 volts per cell) and maintenance free battery (gel) is 33 volts (1.83 volts per cell).  
Note: See the Electrical System for instruction in selecting (setting) the two different thresholds.
* Thermistor: A special semiconductor resistor whose resistance value varies with temperature.
Note: See the “Know Your Machine” section in this manual for a complete explanation for all scrub system operational modes.