Description of Hydraulic Power Packs and Linear Drives for Autopilots
As a general rule, the basic set up of a hydraulic system for autopilot consists of:
- 1 hydraulic cylinder
- 1 hydraulic power pack
- Fittings and tubing to connect the cylinder to the power pack
Other elements will be added to this basic set up in function of the configuration of the boat steering system – hydraulic steering, wire ropes, cables, etc.
The cylinder is the dictating element in the selection of a system. It gives the pushing power to the steering system in function of its effective area and the pressure it receives from the power pack.
To select the cylinder, follow the method given in menu “Selection of the System“.
Hydraulic Power Pack
Power packs are always composed of a reversible or non reversible electrical motor in 12 or 24 volts DC, or 220/240 V single-phased or three-phase, coupled to a reversible or non reversible axial piston pump or gear pump, with adjustable or fixed flow rate.
Receiving orders from the electronics, the power pack will suck or force back the oil in the circuit. The speed of correction is determined in function of the pump flow rate in litres per minute.
Our systems are fitted with lock valves which prevent cylinder movements once the boat is on the desired course until a new course correction is required.
They are also fitted with pressure relief systems to protect the circuit against abnormal pressure increases.
Tubing is designed for hydraulic oil transfer under pressure. Tubing diameter is selected in function of the power pack flow rate.
|When the boat moves away from the displayed course, the autopilot electronic computer sends current to the motor terminals or to the power pack electrovalve. Then, the cylinder will be supplied with oil and set in motion. As soon as the boat is back on the displayed course, the computer stops supplying the power pack and the cylinder stops moving.|