M3 - Scrub Brush Actuator Lift Motor Function; Scrub System Low-Voltage Cut-Out Function - Nilfisk-Advance Adphibian AX 651 Multi EDS Service Manual

M3 - Scrub Brush Actuator Lift Motor Function

The Scrub Brush Actuator continuously raises and lowers the scrub deck as needed to maintain optimum brush contact
with the floor surface. The Scrub Brush Actuator lift motor is controlled by the amount current drawn by the scrub brush
motors as follows:
• If the control board senses that the brush motors are drawing too much current, the Scrub Brush Actuator lift motor
raises the scrub deck until the brush motor current draw is within the acceptable range.
• If the control board senses that the brush motors are drawing too little current, the Scrub Brush Actuator lift motor
lowers the scrub deck until the brush motor current draw is again within the acceptable range.
The A1 control board provides voltage through J2-2 (VIO/YEL wire) and J2-3 (WHT/GRN wire) that changes polarity
to raise and lower the scrub-deck. The large BLK negative (-) scrub brush motor wire is specially designed so that it
has a known (specified) resistance value. As brush motor current passes through the negative wire that is, in effect, a
low-value resistor, a small voltage drop is developed across it which is proportional to the motor current. This voltage
change is inputted to the A1 control board at J3-1 Brush Motor Sense (WHT/GRA wire) and J2-5 (BLK ground). Any
surrounding temperature change in this large negative motor wire affects its resistance, so the temperature is sensed
by a thermistor built into the control board A1. This allows the controller to provide error correction for the temperature
resistance changes. When the controller senses a current draw out of the desired range, it automatically turns on the
M3 actuator motor to raise or lower the scrub deck. This process is ongoing in maintaining the operator's selected
scrub motor current load setting to sustain the desired brush working pressure.

Scrub System Low-voltage Cut-out Function

The purpose of the special low battery voltage cutout function is to help prolong battery life. The scrub deck will be
raised and the brush motors and solution solenoid valves will switch off automatically when the batteries discharge to
the selected cutout level. The cutout level can be set to the standard setting (wet cell/lead acid) of 1.72 volts per cell,
or to the alternate setting (gel/maintenance-free) of 1.81 volts per cell. (See the Main Control Programming Options/
Selection of Low Voltage Cutout Threshold section for instructions for selecting the cutout threshold.
38 - Form No. 56043116 - Adphibian™/AX 651 Multi EDS/AquaPLUS™