
CONTROL SYSTEMS (STEAM AND MOTOR)
for astern running, position of bleed valves, drains and closing in the
manoeuvring valve should the boiler pressure drop below a pre-set value.
In the 'Limiting System' the difference between the desired value and
measured value signals (or the error signal) is limited to keep the boiler pressure,
water level and turbine torque within safe limits by preventing the rate of change
of power becoming too high whilst manoeuvring.
The Timing System is used to regulate the rate of change of power between
Full Ahead and Full Away and vice-versa. It only comes into operation at shaft
speeds higher than Full Ahead bein ...