Traction Drive With Central Command Ii; Brush Lift Electrical Circuit; Down Pressure Adjustment - Factory Cat MINI-MAG SERIES Service Manual

TRACTION DRIVE WITH CENTRAL COMMAND II

The active brush lift system on the MiniMAG series consists of an actuator, down pressure
springs, scrub switch and the controller. The brush deck is raised and lowered by the brush
deck actuator which is driven by the controller. The actuator circuit is internally protected
from electrical overload by the controller. The active bush lift system is used to lower the
brush deck when scrubbing is started and raise it when stopped. The controller continually
monitors the amperage draw of the scrub brushes and raises and lowers the scrub deck
accordingly to keep the motors drawing a consistent amount of amperage thus keeping the
scrub pressure uniform.

BRUSH LIFT ELECTRICAL CIRCUIT

The brush lift electrical circuit consists of two wires that run from the controller to the actua-
tor. Power is applied to the actuator with the polarity in one direction to raise the brush
deck and the opposite direction to lower the brush deck. The actuator has internal limit
switches that prevent it from moving too far in either direction. While the circuit itself is very
simple, the control of this circuit is very complicated. The controller operates the output of
this circuit by monitoring a number of variables. Is important to know this circuit energizes
the brush deck actuator to raise the brush deck for 4 seconds each time the controller is
powered up. For this reason it is important to make sure all body parts are clear from under
the scrub deck when the machine is powered on. When the scrub switch is turned on the
controller runs the scrub brushes down toward the floor for a predetermined amount of time,
typically about 4 seconds. This is known as dock time and can be modified by changing
the parameters of the controller. When the throttle button is depressed the controller moni-
tors the amp draw of the brush motor and adjusts the scrub deck height to obtain the target
amp draw on the scrub motors. The target amp draw of the motors is set using the brush
pressure switch on the control panel. The brush pressure setting is shown on the LCD
display in the form of a bar graph. The target amps for each of the brush pressure settings
are defined by the parameters that are programed into the controller. When the throttle
of the machine is released the scrub brushes raise up off the floor for 2 seconds. This
is called raise time. The purpose of this is so the scrub brushes start up under reduced
load which leads to much longer motor life. Raise time can be modified and is set through
programing. If scrubbing begins again the brushes drop back down to the floor and the
controller again starts analyzing the brush motor amp draw and adjusting the scrub deck
pressure accordingly. When the scrub deck switch is turned off the scrub head raises for
four seconds to it's fully raised position,

DOWN PRESSURE ADJUSTMENT

Down pressure is regulated by the controller on the machine as. The desired brush pres-
sure is selected by using the brush pressure switch on the control panel. The brush pres-
sure selection is read out on the LCD display in the form of a bar graph.. The bar graph is
segmented in to 5 levels the lowest being 1 bar and the highest being 5 bars. The pres-
sure relative to each of the settings is programed into the controller and are fully adjustable..
Mini-Mag Service Manual V1.0
BRUSH LIFT SYSTEM
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