Vehicle Operation; Electrical System Operation - Toro Workman GTX Electric & Lithium Service Manual

Electrical System Operation

Vehicle Operation

The Workman GTX Electric electrical system uses a 48
volt battery pack, an electric traction motor, a vehicle
controller and numerous other electrical components to
allow vehicle operation.
The battery pack is composed of four 48 VDC lithium--
ion batteries that are connected in parallel provide cur-
rent for a 48V, brushless, high torque, AC inductive
traction motor, the vehicle controller and vehicle acces-
sories. The batteries are discharged as the vehicle is
used so charging the batteries after using the vehicle is
necessary. The display on the dash provides the opera-
tor with information on battery charge level.
IMPORTANT: When connecting the battery pack in
the 48 VDC system, make sure that battery polarity
is carefully checked. System damage can occur if
batteries are not connected correctly.
The Workman GTX electrical system is an isolated sys-
tem so the vehicle frame is not used for any ground con-
nections. Before performing any electrical service, it is
recommended to open the vehicle battery circuit by dis-
connecting the conductors between the battery pack
and vehicle components (see Opening Battery Circuit in
the General Information section of this chapter). This will
prevent unexpected component operation when per-
forming service on the vehicle.
The electric traction motor directly drives a double re-
duction, high torque transaxle with integral differential.
Operator inputs for forward/reverse, supervision speed
limit switch position and accelerator pedal position are
used by the controller to determine needed electrical
power for the traction motor.
The traction motor is protected from overheating by a
thermistor (thermally sensitive resistor) that resides in
the motor housing. If unsafe motor temperature is
sensed by the thermistor, the controller will limit vehicle
speed and torque until the motor temperature reduces
to a normal level.
Workman GTX Electric Lithium
The vehicle controller is a sealed electronic logic device
that uses inputs from several vehicle components to
control motor speed and direction. These inputs include
several switches (key, direction selector, speed mode
limit, parking brake), the traction motor thermistor (tem-
perature), the traction motor encoder (speed sensor),
the accelerator pedal and the vehicle main contactor
(solenoid). The controller also provides regenerative
braking to assist in slowing the vehicle whenever the ac-
celerator pedal is released. Battery current is available
to the controller whenever the key switch is ON which
energizes the main contactor. A high current fuse
mounted to the controller protects the 48 VDC circuits.
The Workman controller also limits roll away speed in
instances when the vehicle begins to move (roll away)
after being stopped. On an incline and with the key
switch in the ON position, if the vehicle starts moving, re-
generative braking will limit vehicle speed.
Vehicle accessories (headlights, USB charge port, op-
tional reverse alarm and optional lights) are operated by
a 12 VDC system that is powered by a 48 VDC to 12
VDC converter mounted under the dash panel. These
vehicle accessories receive current for operation when
the key switch is ON. The 12 V fuse block provides cir-
cuit protection for the components in this 12 VDC sys-
tem. Ground wires used for 12 VDC circuits have black
insulation.
An on--board, fully automatic, high efficiency charger
with 85 -- 265 VAC global input is attached to the vehicle
for charging the battery pack. The vehicle controller pre-
vents the vehicle from operating while charging the bat-
teries. Charger activity can be monitored at the display
on the dashboard.
Testing and service information about components used
in the Workman GTX electrical system is included in the
Component Testing and Service and Repairs sections
of this chapter.
Page 3B - - 5 Electrical System