COUPLING ASSEM. (STRAIGHT) 6V9953 - Caterpillar

3500 Family Of Generator Sets And SI (Spark Ignited) EnginesReference: Service Magazine, April 9, 1984, Page 2, "Overvoltage Protection For Woodward 2301 Governor".Reference: Special Instruction SMHS8363, SELS0115 and Service Manual (SENR2928-01) for 2301 Governors.Description of Change: The load sharing electric governor is an optional governor for the 3500 Family of Generator Sets and SI Engines. Formerly, the optional load sharing electric governor was a Woodward 2301 Governor. Now, this optional load sharing electric governor is a Woodward 2301A Governor. The standard 2301 Speed Control Governor (sometimes called standby control) has not changed. The most important improvement of the 2301A Governor is the extended power supply voltage range. Thus, the 4W5391 Box Assembly (preregulator) is not required to protect the 2301A Governor from high voltage spikes and surges. See Reference Article. Other improvements are: ... The cold start relay, that is frequently required when the preregulator is used, is also not required. Special Instruction SMHS8363 covers installation of this part if needed.... The internal power supply in the 2301A Governor is electrically isolated, eliminating the need for a high voltage selector (best battery selector). The potential for problems with grounding and governor incompatability have been reduced.... The 2301A Governor can be adjusted for engines having much different dynamic characteristics.... A high quality load sharing relay is not required in the load sharing lines. The 2301A Governor contains its own load sharing relay.... A start-fuel limit feature has been added to reduce overfueling at start-up.... Excessive contact resistance in the idle-rated switch will not affect speed.
There are many other differences between the 2301 and 2301A Governors. It is important that the people installing and adjusting the engines and switch gear be aware of these many differences and refer to the Special Instruction SELS0115, "Installation Of 2301A Load Sharing Control Group".
Adaptable To: The 7C246 Governor Control Assembly (2301A) can be used to replace the former 4W5395, 8N409, 4W5394, or 8N6728 Governor Control Assemblies (2301). The Special Instruction comes with each new governor. The instructions cover installation of the new governor in combination with either the former governor or with other new governors, or as a replacement for the former governor. The following topics explain in more detail the differences between the two governors and cover new prestart and operation adjustments.
Differences Between 2301 And 2301A Governors
Terminal Numbers Change
The terminals used for the various interface connections have changed. These are shown in the following Chart and in the Special Instruction. Only terminals one through eleven remain the same.
Terminals That Have New Functions
The minimum fuel and defeat failsafe functions now use normally open contacts, or no connections, where normally closed contacts, or jumpers, were used previously.
Two Functions No Longer Used
The functions for former terminals 28 and 25 are not required on the 2301A Governor. However, these two terminals are still used with different functions assigned. See Chart.
Added Terminals
Load signal terminals 12 and 13 are now located on the terminal strip. Terminals 12, 22 and 27 are common terminals to be used for shield connections.