Steering Drive Unit; Rudder Feedback Unit - Vetus FOLLOW-UP STEERING Manuel D'utilisation Et Instructions D'installation

3.6 Steering drive unit

The Follow-Up steering system can work with one of the follow-
ing sorts of steering drive units:
- electro-hydraulic pump with reversible motor
- electro-hydraulic pump met continuously running motor
(in one direction) and solenoid valves
- rotating electro-mechanical drive unit
- linear electro-mechanical drive unit
Choice of steering drive unit, total hard-over time
The total hard-over time does not influence the operation of
the Follow-Up steering system but a shorter time will, however,
make the steering react more quickly to commands and this
generally gives more comfortable steering behaviour.
When an autopilot is being used the total hard-over time does
have an effect on the steering behaviour. The steering drive unit
installed must be capable of operating the rudder with the fol-
lowing total hard-over times (seconds):
- for a ship displacing water: between 1.2 x OL and 1.8 x OL
- for a surface ship: between 1 x OL and 1.3 x OL
OL is the Overall Length in metres.
Calculation of the EHP (Electro-Hydraulic Pump) required for a
ship with hydraulic steering system:
(This calculation applies to both an EHP with reversible motor
and an EHP with continuously running motor and solenoid
valves.)
Determine the capacity of the cylinder which is already installed
or will be installed. See the technical specifications for the partic-
ular hydraulic steering system as supplied by the manufacturer.
Divide the cylinder capacity by the required total hard-over time
in order to determine the capacity of the EHP to be chosen.
Example
:
The required total deflection time is 15 seconds
The hydraulic steering cylinder has capacity of 150 cm3.
Therefore the EHP must have capacity of :
3
Cylinder capacity in cm x 60
hard-over time in seconds
28
100901.02
3
150 cm x 60
= = 600 cm
15 s
Connecting the steering drive unit
See diagram 7.2 for the connections to the steering drive unit.
The current for a reversible motor * runs from the connecting
cables from the battery to the electronic control unit and from
there to the motor.
*) electro-hydraulic pump with reversible motor, rotating electro-
mechanical drive unit or linear electro-mechanical drive unit
Use connecting cables with sufficiently large cross-sectional
area.
Where a non-reversible motor is used (electro-hydraulic pump
with continuously running motor and solenoid valves) only the
current for the solenoid valves runs though the connecting
cables. Use cable with cross-sectional area 1.5 mm

3.7 Rudder feedback unit

The rudder feedback unit reports the angle of the rudder back
to the Follow-Up steering system.
The rudder feedback unit (Vetus art. RFU1718) must be pur-
chased separately.
If a Vetus rudder feedback unit is already installed for an auto-
pilot or display meter it must be connected as described in this
manual.
3
/min
It is therefore not necessary to install separate rudder feed-
back unit for a Vetus autopilot or one or more Vetus rudder
position display instruments.
Power supply
The rudder feedback unit
must be connected to the 5
Volt power supply provided
by the Follow-Up system.
The connector must be put
to the '5V' position as shown
in the drawing.
2 .
Follow-Up Steering System Follow-Up Steering System