Pedals; Service Brake Pedal; Dynamic Retarder Pedal; Throttle Pedal - Komatsu 730E Operation & Maintenance Manual

OM3241
Operator Cab and Controls

PEDALS

FIGURE 32-4. PEDALS
1. Cab Floor

2. Service Brake Pedal

SERVICE BRAKE PEDAL
Service brake pedal (2, Figure 32-4) is a foot-oper-
ated pedal which applies the service brakes.
NOTE: In some optional installations, the service
brake pedal may not be present, because it is
incorporated into a single pedal function with retarder
pedal (3).
3. Dynamic Retarder
Pedal

4. Throttle Pedal

DYNAMIC RETARDER PEDAL

Dynamic retarder pedal (3, Figure 32-4) is a foot-
operated pedal which allows the operator to slow the
truck and maintain a safe productive speed without
the use of the service brakes. For normal truck oper-
ation, only dynamic retarding is used to slow and
control the speed of the truck. Refer to Grade/Speed
Warning chart to determine the maximum safe truck
speeds for descending various grades with a loaded
truck. Apply the service brakes only when dynamic
retarding requires additional braking force to slow the
truck speed quickly and to completely stop the truck.
When dynamic retarding is activated, the engine rpm
will automatically go to an advance rpm retard speed
setting (usually 1250 rpm, see note below.) Dynamic
retarding will be applied automatically if the speed of
the truck reaches the predetermined overspeed
retard setting. Dynamic retarding is available in FOR-
WARD/REVERSE at all truck speeds above 0 kph
(mph) but is available in NEUTRAL only when the
truck speed is above 5 kph (3 mph).
NOTE: The exact engine speed in retarding may vary
(1250 - 1650 rpm) due to the temperature of certain
components, This is controlled by the Statex III
control system.
THROTTLE PEDAL
Throttle pedal (4, Figure 32-4) is a foot-operated
pedal which allows the operator to control the engine
rpm, depending on the pedal depression.
Operation - Section 32
Page 32-3