The Drinking Water Discharge Winch and Levelwind are driven by a dual hydraulic power system. The winch is
driven by a closed-loop circuit with a variable displacement piston pump, and the levelwind is driven by an open loop
circuit with a fixed displacement gear pump.
Figure 4-1 shows the circuit schematic for the system. The hydraulic power package component arrangement is
shown in Figures 4-2 and 4-3. The item numbers in this section refer to the numbers indicated on the schematic.
Specific information pertaining to the hydraulic components is contained in the Appendices.
Certain elements of the hydraulic system are common to both circuits. The immersion oil heater in the reservoir
(13) is used to bring the hydraulic fluid up to the proper operating temperature and viscosity in cold weather conditions. It
is controlled by the rotary switch on the electrical enclosure, and by the automatic control system. A red indicator light is
illuminated when the heater is in operation. The level/temperature switch (12) in the reservoir is used to shut down the
system in the event of excessively high or low oil temperature or low oil level.
The heater contactor will automatically open if any one of four conditions exist:
- Low oil level (level switch open)
- High oil temperature (high temperature switch open above 180° F)
- Thermostat open (set for 100° F)
- Manual rotary switch turned off by operator.