Start Fuel Limit Adjustment; Speed Sensor Check; Droop Adjustment - Woodward 2301A Installation And Operation Manual

2301A Speed Control with mA Speed Setting Input

Start Fuel Limit Adjustment

NOTE
Start-fuel limit is not recommended for use with reverse-acting controls.
With loss of speed signal, the reverse acting control will position the
actuator at the start-fuel level if the failed-speed-signal override is activated.
Reverse-acting systems normally require the control to demand full fuel on
loss of speed signal to allow the mechanical backup governor to control the
system. The Start Fuel Limit can be deactivated by turning the potentiometer
fully clockwise.
With the prime mover operating at desired speed and no load, record the voltage
across the actuator terminals 9 (+) and 10 (–). Shut down the prime mover and
activate the Failed Speed Signal Override by closing the override contact. The
voltage to the actuator should now be adjustable by the START FUEL LIMIT
potentiometer. Set the actuator voltage about 30 percent higher than the voltage
obtained at rated speed for forward-acting controls and 30 percent lower than
rated speed voltage for reverse-acting controls. Remove the Failed Speed Signal
Override contact if not required to start the prime mover.
Start the prime mover and observe the start time, overshoot of speed setting,
and exhaust smoke obtained. If the prime mover does not start, turn the START
FUEL LIMIT potentiometer slightly clockwise until the prime mover starts. The
START FUEL LIMIT may be adjusted as required to optimize the prime-mover
starting characteristics. The fuel-limiting function is turned off automatically when
the speed control takes over.
NOTE
For prime movers not requiring start-fuel limiting, the START FUEL LIMIT
function can be deactivated by turning the potentiometer fully clockwise.
If the sensor is a magnetic pickup, measure the voltage across terminals 7 and 8
to be sure there is a minimum of 1.0 volts at cranking speed, and a maximum of
30 Vrms at rated speed. If the voltage exceeds 30 V, increase the gap of the
speed sensor, and be sure that there is still a minimum of 1.0 V at cranking
speed.
The amount of droop is not critical in many installations. If the engine needs to
run in droop but the amount is not critical set the droop potentiometer in mid-
position, then adjust load with the Rated Speed/Low Limit potentiometer or the
speed setting signal..
When paralleled with an infinite bus, the generator frequency cannot change,
and unless a load- sensing module is being used, the control must be in droop to
maintain stable operation. With the droop potentiometer at mid-position, parallel
the generator, then increase the Rated Speed/Low Limit potentiometer until the
desired amount of load on the engine is achieved.
Too much droop will cause the engine to overspeed should the load be suddenly
lost. Excessive droop will also cause the engine to be sluggish in response to
load changes.
18

Speed Sensor Check

Droop Adjustment

Manual 02302
Woodward