9905-463  Load Sharing and Speed Control

The 9905/9907 series of the Woodward 2301A controls load sharing and speed of generators driven by diesel or gasoline engines, or steam or gas turbines.

These power sources are referred to as “prime movers” throughout this manual.

The control is housed in a sheet-metal chassis and consists of a single printed circuit board. All potentiometers are accessible from the front of the chassis.

The 2301A provides control in either isochronous or droop mode.

The isochronous mode is used for constant prime mover speed with:

Single-prime-mover operation;

Two or more prime movers controlled by Woodward load sharing control systems on an isolated bus;

Base loading against an infinite bus with the load controlled by an Automatic

Power Transfer and Load (APTL) Control, an Import/Export Control, a Generator Loading Control, a Process Control, or another load-controlling accessory.

The droop mode is used for speed control as a function of load with:

Single-prime-mover operation on an infinite bus or

Parallel operation of two or more prime movers.

The following is an example of the typical hardware needed for the 2301A system controlling a single prime-mover and generator:

A 2301A electronic control

An external 20 to 40 Vdc power source for low-voltage models; 90 to 150

Vdc or 88 to 132 Vac for high-voltage models

A proportional actuator to position the fuel-metering device, and

Current and potential transformers for measuring the load carried by the generator.

9905-973

The 2301A 9905/9907 series electronic controls have switch-selectable speed ranges. Any of these control models can be set to operate within one of the

following rated speed ranges:

500 to 1500 Hz

1000 to 3000 Hz

2000 to 6000 Hz

4000 to 12 000 Hz

These controls are available for forward- or reverse-acting applications, and for use with either single or tandem actuators. Models for three different actuator

current ranges are available, as well as a high-voltage model (90 to 150 Vdc or 88 to 132 Vac, 45 to 440 Hz), and a low-voltage model (20 to 40 Vdc). The high

voltage model is identified as such on the front; the low voltage model is not. In reverse-acting systems, the actuator calls for more fuel when the actuator

voltage decreases. Complete loss of voltage to the actuator will drive the actuator to full fuel. This allows a backup mechanical ballhead governor to take control

rather than shut down the prime mover as would a direct-acting system. An optional deceleration ramp is also offered. When this option is present, the

time to ramp from rated speed to idle speed is approximately 20 seconds. If this option is not present, this happens instantly.

Tables 1-1 and 1-2 show part numbers and features of all 9905/9907 series 2301A load sharing and speed controls.