Scrub System, Disc
124
Service Manual – SC6500
™
Circuit Description
The coil sides of contactors
K2
,
K3 and K4
get positive voltage from the
Battery
when the load side of contactor
K5
is closed. Contactor
K5
closes when the
A2 Control Board Assembly
connects the
K5
coil to battery ground.
Contactors
K2
,
K3
and K4
are connected to battery ground through the
A2 Control Board Assembly
.
The
Right Brush Motor M9
,
Center Brush Motor M10
and
Left Brush Motor M11
get positive voltage from the
Battery
when the load sides of contactors
K2
,
K3
and K4
are closed respectively. Contactors
K2
,
K3
and K4
close
when the
A2 Control Board Assembly
connects the
K2
,
K3
and K4
coils to battery ground. The
Right Brush Motor
M9
,
Center Brush Motor M10
and
Left Brush Motor M11
are connected directly to battery ground.
The
Brush Actuator M2
gets voltage from the
A2 Control Board Assembly
which switches the polarity to move
the scrub deck up or down. When the
A2 Control Board Assembly
receives a signal from the
A3 Switch/Display
Panel Assembly
via the CAN BUS that the operator has pressed the scrub on switch, the
A2 Control Board
Assembly
sends the appropriate voltage to the
Brush Actuator M2
to lower the scrub deck to the operating
position.
The
Scrub Deck Sensing Resistor R2
senses the deck size so the operator does not need to program the deck
size into the hidden menu.
As the brush motor current passes through the
BRN
current sense wire, which 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 pin
J2-2
on the
A2 Control Board Assembly
. Any surrounding temperature change in
the
BRN
current sense wire affects its resistance, so the temperature is sensed by a thermistor built into
the
A2 Control Board Assembly
. This allows error correction for the temperature resistance changes in the
BRN
current sense wire. When
A2 Control Board Assembly
senses a current draw out of the desired range it
automatically turns on the
M2
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.