Gensets are characterized by their ability to adjust to changes of loads. These changes are governed by the genset governor, which is usually attached to the fuel injection pump. In newer engines, adjustments to loads are controlled by the ECU, which in turn controls the injectors.

There have been three major steps in genset governors development:

  • Mechanical Governors
  • Speed Control and Actuator-controlled Electronic Governors
  • ECU-controlled Electronic Governors

It is quite commonplace to have older gensets with Mechanical Governors be upgraded with Electronic Governors. In this case, a set of speed control and actuator is added to the genset.

Governors America Corp. (GAC) is one of the most commonly used brands for such upgrades. We provide the following GAC items:


A high performance, speed control system results when a GAC actuator is installed on an engine and electronically connected to compatible GAC governing system components. The design baseline for GAC actuators incorporates fast responses, multi voltage usage, and proven reliability to allow for more precise control. GAC employs its field proven electromechnical design which provides proportional actuator movement based on actuator coil current.

All of GAC actuators are easy to install with no maintenance required. GAC also offers a complete line of speed control devices for use with our actuators, all of which are 100% field-proven tested.

  • ADD175-A-24 (Bosch “P” Type – Pump Mounted – 24VDC – Up to 12 Cylinder Pumps)
  • ACE275H-24 (Bosch “P” Type – Pump Mounted – 24VDC – Up to 8 Cylinder Pumps)

Speed Controls

GAC’s Speed Control Units are precise speed controls designed and manufactured in various configurations to meet application requirements using the latest analog and digital control technologies. Reverse battery polarity and fail-safe protection in the event of loss of speed sensor signal or battery voltage is incorporated in every GAC Speed Control Unit.

A wide variety of application needs can be satisfied with GAC’s constant or variable speed governing, in isochronous or droop operation. All circuit boards are hard potted or conformally coated to be vibration and moisture resistant.

  • ESD5500E (Isochronous, Variable, & Droop Operation / Switchable Droop Control / Starting Fuel Control / Speed Ramping / Soft Coupling / Overspeed Control Switch / Auxiliary Output)
  • ESD5221 (Speed Anticipation Circuit / Adjustable PID Functions / Reverse Voltage Protection / Overspeed Contact / 10 Amp Relay Output / Isochronous, Variable, & Droop Operation / Single Element Speed Switch)

Magnetic Pickups

The Magnetic Speed Sensor detects when ring gear teeth, or other ferrous projections, pass the tip of the sensor. Electrical impulses are produced by the sensor’s internal coil and sent to the speed control unit. The signal from the magnetic speed sensor, teeth per second (Hz.), is directly proportional to engine speed.

  • MSP6721C (81 mm Length / 70mm Harness Length / Standard Connector / With Mating Connector)

Please contact us for all your Genset Governors needs. Application, installation, need for parts, or servicing are available. Other part numbers are also available. Please inquire with us for quotes.