Group 16, Electrical Motors
16-1-2 • Motor Specifications and Descriptions SM 765, Nov ’06
Description and Location
The truck has three electric AC motors:
• Two identical traction motors
• One main hydraulic/power steering pump motor.
Drive motors
The two drive motors are three-phase AC motors with
class F insulation. These motors do not use brushes and
the motors are totally enclosed, minimizing the service
requirements. Because the motors do not use brushes and
are enclosed, sealing them from outside contamination,
there is no need to blow out the inside of the motors dur-
ing a PM. Each motor has two bearings; the drive end
bearing is a ball bearing and the bearing at the rear of the
motor is a special encoder bearing (sensor) for motor
feedback to the control. One motor drives the left traction
wheel, the other the right. The electronic control system
varies the speeds to the two motors independently to
accommodate cornering.
The external connections are easily accessible from the
top of the motor where they are protected from external
damage.
Each drive motor also has a built-in thermistor which con-
stantly monitors the winding temperature and reports this
information to the control (this sensor is not serviceable).
Should it sense that the motor is approaching the tempera-
ture limit, the control will cutback motor current until the
temperature decreases. Since it is cutting back current and
not voltage, the top end speed will not be effected, unless
on a grade.
Lift/Steer pump motor
The pump motor is a three-phase AC motor with class F
insulation. It is also a brushless motor and totally
enclosed. Because the motors do not use brushes and are
enclosed, sealing them from outside contamination, there
is no need to blow out the inside of the motors during a
PM. This motor has two bearings; the drive end bearing is
a ball bearing and the bearing at the rear of the motor is a
special encoder bearing (sensor) for motor feedback to the
control. An electronic control system controls the speed of
the motor at all times. This pump runs for steering any
time the truck is in gear, or anytime a hydraulic function is
requested.
The external connections are easily accessible from the
top of the motor where they are protected from external
damage.
The pump motor also has a built-in thermistor which con-
stantly monitors the winding temperature and reports this
information to the control (this sensor is not serviceable).
Should it sense that the motor is approaching the tempera-
ture limit, the control will cutback motor current until the
temperature decreases. Since it is cutting back current and
not voltage, the top end speed will not be affected, unless
the loads are close to capacity.
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