When the winch is not in operation, or when the control lever is released, the handle returns to the center, or BRAKE-ON, position by spring force. Any load attached to the winch cable is held firm.
Moving the control lever in the direction of tractor forward movement provides a signal to direct the oil to the winch motor to pull the cable and load in to the winch. REEL-IN drum speed is proportional to the amount of lever movement. When released, the lever will return to BRAKE-ON and the winch drum will stop and hold the load firm.
Moving the control lever in the direction of tractor reverse movement provides a signal to direct the oil to the winch motor to rotate in the direction to power out the cable. REEL-OUT drum speed is proportional to the amount of lever movement. When released, the lever will return to BRAKE-ON and the winch drum will stop and hold the load firm.
NOTE: When operating in REEL-OUT mode, the pressure compensator within the motor is disabled and the winch will work in high speed mode ONLY. This feature ensures control of loads lowered on hillsides, such as yo-yo operations on pipeline right-of-ways.
Drum Clutch Release (Brake-Off)
Depending on the tractor, the drum clutch is operated by either a switch on the tractor console or by the operator joystick. The switch energizes a solenoid to send pilot oil to the drum clutch piston, and the joystick sends the pilot oil directly to the drum clutch piston. Both operations direct hydraulic oil at pilot pressure to the drum clutch in the carrier clutch assembly which moves the drum clutch piston creating clearance between the friction and steel plates in the carrier clutch. This allows the secondary sun gear to rotate disengaged from the primary gear seat and the winch brake. With the drum clutch released, the operator can drive away from a load using the inherent resistance of the two final planetary gear stages to keep a tight wrap of cable on the drum to prevent cable-over-run. When the lever is moved to the BRAKE-OFF position, pilot pressure is directed to the drum clutch releasing it until the joystick is returned to brake on.
As long as the BRAKE-OFF function is active, an indicator light on the main instrument panel in front of the operator will remain lit.
From the operator's perspective, this is the normal and most simple winch control method.
The winch line speed, or drum rotation speed, may be controlled by moving the control lever a very small distance, or by operating the tractor engine, and therefore the tractor implement pump, at a lower RPM.
NOTE: Operating the tractor engine at the lowest idle setting while winching may result in erratic winch operation. Always operate the tractor at high engine idle to provide the full range of control from the winch, while guaranteeing smooth operation. Operating the engine at lower settings will NOT provide slower winching.
The hydraulic motor used with the "autospeed" control system is a variable displacement, piston-type motor with an internal load-sense circuit. This circuit contains a small piston which adjusts the angle of the motor rotating group from minimum to maximum displacement as the pressure on the work ports (A & B) increases due to the load applied to the winch gear train. When there is little or no load on the winch, the motor rotating group will remain at the preset minimum displacement so maximum speed is available. As the winch load increases, the pressure at the motor work ports will increase. This same pressure will also act on the load-sensing piston beneath the "X" and "G" ports. As the load-sensing piston moves, it directs oil to the motor rotating group shift cylinder which increases the motor displacement to provide increased torque, or pulling power, at a slower line speed.
In this manner, the motor displacement will automatically adjust to provide the maximum hydraulic horsepower for any given line speed and line pull situation.
Low-Speed Lock Mode (Low Lock)
Depressing the button near the top of the control lever or a switch on the console will force the variable displacement motor to shift the piston to the maximum displacement position, which will allow the winch to operate in the maximum line pull, minimum line speed mode, to enhance precise load control. When shifted into LOW-LOCK, an indicator light on the main operator instrument panel will remain lit. To disable LOW-LOCK, and return to autospeed mode, press the button again. The indicator light will be off.
On some tractors a toggle switch located on the RH operator's console adjacent to the winch control lever may be switched to completely lock out the hydraulic signal to the winch. This can be performed during servicing, or to eliminate the possibility of accidental winch actuation when performing general dozing operations. When activated, an indicator light on the main operator instrument panel will remain lit.