Service Brake Pedal; Dynamic Retarder Pedal; Throttle Pedal; Heater / Air Conditioner Vents - Komatsu 730E Operation & Maintenance Manual

OM3035.2 02/03
Operator Cab and Controls

SERVICE BRAKE PEDAL

The Service Brake Pedal (2, Figure 3-1) is a foot-
operated pedal which applies the service brakes.
NOTE: In some OPTIONAL installations, this pedal
may not be present, because it is incorporated into a
single pedal function with the Retarder Pedal (3).

DYNAMIC RETARDER PEDAL

The Dynamic Retarder Pedal (3, Figure 3-1) 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 should be used to slow
and control the speed of the truck. The Grade/Speed
Chart (8, Figure 3-1) should always be followed to
determine MAXIMUM safe truck speeds for descend-
ing various grades with a loaded truck. Service
brakes should be applied only when dynamic retard-
ing requires additional braking force to slow the truck
speed quickly and to bring the truck to a complete
stop.
When dynamic retarding is in operation, the engine
RPM will automatically go to an advance RPM retard
speed setting (usually 1250 RPM)*. Dynamic retard-
ing will be applied automatically, if the speed of the
truck reaches the predetermined overspeed retard
setting. Dynamic Retarding is available in "Forward/
Reverse" at all truck speeds above 0 mph/kph, but is
available in "Neutral" only when truck speed is above
3 mph (4.8 kph).
* 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.
OPTIONAL - DUAL FUNCTION / SINGLE PEDAL
The Dynamic Retarding/Brake Pedal is a single foot-
operated pedal which controls both retarding and
service brake functions. Thus, the operator must first
apply, and maintain, full dynamic retarding in order to
apply the service brakes.
When the pedal is partially depressed, the dynamic
retarding is actuated (actuation is modulated). As the
pedal is further depressed, dynamic retarding is fully
applied; then, while maintaining full retarding, the
service brakes are actuated (a slight increase in
pedal resistance will be felt) through a hydraulic
valve, which modulates pressure to the service
brakes. Completely depressing the pedal causes
full application of both dynamic retarding AND
the service brakes.

THROTTLE PEDAL

The Throttle Pedal (4, Figure 3-1) is a foot-operated
pedal which allows the operator to control engine
RPM, depending on pedal depression.
Reference: Figure 3-1

HEATER / AIR CONDITIONER VENTS

The operator has complete control of the air flow in
the cab. The heater/air conditioner vents (5, Figure 3-
1) are a flapper type which may be individually
opened or closed and may be rotated 360° for opti-
mum air flow. There are four (three not shown)
across the top of the panel, two in front of the opera-
tor (one each in right and left panel modules), and
four below the panel.
Operation - Section 3
Page 3-15