HOUSING 2566488 - Caterpillar

Illustration 4 shows the effect of the torque limiter (3) on the maximum flow rate for the machine with the torque limiter open. The initial flow on the charts is low. This reflects the standby pressure from the pump. When oil flow is required, the pump increases the flow of oil. The flow of oil decreases as the pressure in the system increases.The flow compensator spool (2) regulates pump flow when the system pressure and the flow requirements are below the curves in the upper right corner.Line (D) indicates the position of the torque limiter's control over the pump. The torque limiter will destroke the pump as the system pressure increases. The rate of destroke will parallel the torque curve of the engine.Line (A) indicates when the solenoid for the torque control has been energized. The pump provides more oil flow to the hydraulic system.Parameters for the Solenoid for Torque Control with the Direction Selector (Loader)
Table 1
Use of the Direction Selector with the New Solenoid for Torque Control (Loader Operation)    
Model     The Solenoid is Energized.     The Solenoid is De-energized.    
    High Torque     Low Torque    
450E     1600 rpm     1200 rpm    Table 1 lists the operating parameters for the solenoid for torque control. When the solenoid is energized, the pump is in the high torque mode. When the solenoid is de-energized, the pump is in the low torque mode.When the direction selector is in the FORWARD or REVERSE, the new solenoid for torque control (4) will not be energized until a certain engine rpm is obtained. The solenoid for torque control (4) is not energized until the engine reaches a higher engine speed. Then, all of the power from the engine can be utilized by the power train.When you operate the machine, the power train system and the hydraulic system will utilize the engine horsepower. When the solenoid for torque control (4) is energized or de-energized due to the engine rpm, there is a slight delay in operation. The delay occurs when you change the direction selector. The delay will help stabilize the engine and the hydraulic system.Parameters for the Solenoid for Torque Control without the Direction Selector (Backhoe Operation)
Table 2
The New Solenoid for Torque Control Without the Direction Selector (Backhoe Operation)    
Model     The Solenoid is Energized.     The Solenoid is De-energized.    
    High Torque     Low Torque    
450E     1200 rpm     1100 rpm    Table 2 lists the operating parameters for the new solenoid for torque control (4) without the use of the direction selector. When the solenoid is energized, the pump is in the high torque mode. When the solenoid is de-energized, the pump is in the low torque mode.When the direction selector is in the NEUTRAL position, the new solenoid for torque control (4) will not be energized until a certain engine rpm is obtained.When the direction selector is in the NEUTRAL position, the solenoid for torque control