Circuit Descriptions; Vacuum Motor Off - Nilfisk-Advance Advance SC1500 Service Manual

Service Manual – SC1500
• The
Solid State Relay
voltage to the
Vacuum Motor
the has an LED that
Solid State Relay
lights when the
Relay
• The
Flyback Diode (D2)
voltage spike through the Solid State
Relay that can occur when the Vacuum
Motor is switched off. The inductive
nature of the motor can cause a large,
reverse polarity voltage spike across
the solid state relay. The flyback diode
permits this energy to be dissipated
through the motor windings without
the large voltage buildup at the relay.
The flyback diode uses a bridge
rectifier simply for its power handing
capabilities.
Also refer to "Squeegee System"
operation.

Circuit Descriptions

Vacuum Motor Off

Bat +
SPST Key
Switch
S1
BRN/VIO BRN
1 2
CB3
BLU/ORN
1
2
Circuit Breaker, 20 Amp
Solid State
When the
Vacuum Motor
• The switch on
Brake -
the line on pin
Motion Input
• The
Vacuum Contactor
the
M4 Vacuum Motor
( ) controls the
K1
. Note that
is on.
reduces the high-
on page 106 for more information on the squeegee components and
Control Board
Vacuum
Contactor
GRA/BLK
J3-12
Motion Input 24v
WHT
Relay (K1)
1 2
M4
M
Vacuum
Motor
Fly-back
D2
+
Diode
~ ~
-
is off:
in the
Pin 6 E1 Curtis Speed Controller
on the
J3-6 A1 Control Board
switch on pin is open, the
J3-12
is off.
Fly-back
Diode (D2)
A1
Bat -
RED/WHT
J3-6
24v
is open and is not sending the drive signal to
Solid State Relay (K1)
Recovery System
Solid State
Relay (K1)
Bat -
E1
Curtis 1210
Speed
Controller
Pin 6 Brake -
Bat -
is de-energized and open, and
67