8901-457 WOODWARD

The RATED SPEED potentiometer, adjusted so the converter-speed voltage 

and the reference-speed voltage are equal at the desired operating speed. 

· The LOW IDLE potentiometer, adjusted so the reference voltage is correct 

for the desired idle speed. 

· The START FUEL LIMIT potentiometer to provide a means of limiting the 

fuel-rack position when starting diesel engines. Adjustment of the 

potentiometer sets the maximum actuator position from no speed until the 

speed control calls for a fuel setting lower than the setting of the start-fuel 

limit. The limit is automatically placed in the circuit whenever the speed 

monitor input declines below the Failed Speed Signal level. Setting the Start 

Fuel Limit potentiometer full cw will raise the limit above the maximum fuel 

position, making the limit non-effective. 

· RESET, GAIN, and ACTUATOR COMPENSATION potentiometers adjust 

the control amplifier to accommodate various types of prime-movers. Reset 

adjustment affects reaction time when recovering after a sudden load 

change. The magnitude of the speed change resulting from a sudden change 

in load is controlled by adjusting the Gain potentiometer. Actuator 

Compensation compensates for the time the actuator and prime-mover 

system take to react to signals from the control. 

· The RAMP TIME potentiometer sets the time required for the prime mover to 

accelerate from idle to rated speed. 

Droop and Speed Trim settings change at 10% of the existing 

reference per volt. The Auxiliary input causes a 3% speed change per 

volt. The Synchronizer input causes a 0.666% change of reference 

speed per volt. 

Actuator Circuit Protection 

The speed control is protected from shorts or overloads in the actuator circuit at 

terminals 9 and 10 by an automatic circuit breaker. The circuit breaker will reset 

automatically after the short or overload is corrected and the control has a few 

minutes to cool down. 

Reverse Acting Controls 

The reverse-acting 2301A Speed Control and its actuator are designed so that 

zero voltage to the actuator corresponds to maximum fuel to the prime mover. 

The actuator usually used with a reverse-acting control has a mechanical 

governing mechanism included (see Figure 4-3). The speed setting of this 

mechanical governor is slightly higher than the speed setting of the 2301A. 

Should the electronics fail, the actuator will try to go to maximum fuel but will be 

stopped when it gets to the speed setting of the mechanical governor, providing 

continued operation of the prime mover, although at a speed which is slightly 

higher than the electronic control speed reference.