1993/05/03 Caterpillar

Governor Control Adjustment {1264}

Usage:

G3508 (2JF),
G3512 (4KC),
G3516 (3RC) Engines Equipped With Woodward 701 Digital Speed Control (Caterpillar 4P6546 Governor Control Assembly) Attachment

Features Of The Woodward 701 Governor

The Woodward 701 Governor is used where applications demand different governor response times for various modes of operation. This governor is programmable so that the end user can create a variable governor gain (variable response time) to optimize engine performance. Variable governor gain allows low gain for better stability at steady-state conditions and high gain during periods of changing loads. Control gain is programmed as a function of speed error and a function of engine load.

The 701 Governor also offers a multiple dynamics menu. This governor can store two different groups of governor dynamic settings. During stand alone operation, a group of preprogrammed fast dynamic settings is automatically selected. When the unit is operating in parallel with a utility, a group of preprogrammed slow dynamic settings is automatically selected. This feature allow optimum governor gain during each application.

The current Woodward 2301 and 2301A governors do not offer programmable variable gain settings. Instead, the governor gain is manually set and remains constant throughout all modes of engine operation. The 701 Governor will provide improved performance over a 2301A Governor when both of the following criteria are met:

* When an installation involves an auto paralleling device.

* When a unit is paralleled to a utility grid even briefly during load transfer.

Installation Requirements

The 701 Governor must be able to access and determine when the unit is paralleled to the utility. Alternate dynamic terminals are provided to meet this need. In some applications, this logic signal must be in series with both the generator breaker and the utility breaker to provide the correct logic to the governor.

Programming Procedures

The 701 Governor is programmed with a hand-held 700 Set Point Programmer (Caterpillar Part Number 4P6547 Programmer). Programming is simplified by a menu driven system with the following four categories:

* Menu A-Governor Dynamics

* Menu B-Engine Speed Setting

* Menu C-Fuel Limiters and Control Output

* Menu D-Engine Display

The Woodward 701 Operators Manual (Woodward Manual Code 85132A) contains programming instruction and setup for the unit. Initial governor settings for G3500 Engines can be found in Menus A, B, C, and D. These initial settings can be changed to optimize engine performance under various modes of operation.

Two groups of dynamic setting exist for the governor. See Menu A-Dynamics Menu. Settings one through six define one group while settings seven through twelve define another. The auxiliary contacts on the utility tie breaker connect to Terminal 13, Discrete Input E, on the 701 Governor. When this contact is open, the first group of dynamic settings is selected. When this contact is closed, the second group of dynamic settings is selected.

Control maps for control gain versus speed error and control gain versus control input are shown in Illustrations 1 through 4. The plots map the recommended initial settings under specific engine applications.

Illustration 1. control gain as a function of speed error. Recommended gain map for use when the unit is in stand-alone operation not paralleled to a utility bus (Gain 1).

Illustration 2. Control gain as a function of control output. Recommended gain map for use when the unit is in stand-alone operation not paralleled to a utility bus (Gain 1).