ESD5500E Series
The most popular analog Speed Control in the world.

GAC’s ESD5500E Speed Controller is a long- standing, versatile, very popular speed control unit that can be applied to multiple engine / actuator applications.

It features:

  • Isochronous, Droop & Variable Speed Operation
  • Idle Control and Speed Trim Capability
  • Starting Fuel and Speed Ramping Adjustment for Black Smoke Control
  • Load Sharing & Synchronizing Capable
  • Marine Certified View Certifications

The ESD5XXX series controllers are available in a wide variety of options for both diesel and natural gas applications. See the table below for our most popular versions.



GAC ESD5500E Series Speed Control Controlling a Cummins KTA50-G9 – 2220 HP, 50L, V16 Engine

A Steel Mill in Brazil’s Minas Gerias State, contracted Distribuidora Cummins Minas Ltda (DCML)., the largest Cummins Distributor in Brazil, to install and maintain their emergency cooling water system that requires the capacity to displace 3600m3 of water per hour (over 951,000 gallons per hour).   

DCML installed a KTA50-G9 engine with a PT fuel system and EFC actuator, controlled by an ESD5500E series speed control, to drive the water pump.  The pump runs on an automated system and will come on-line if there is a power failure or any other interruption in their cooling water supply.  It’s programmed to start in idle speed control for 20 seconds then accelerate under speed ramp control to 1800 RPM.  The rate of acceleration is set to correspond with the opening rate of the water repression valve.  The system is programmed to run for one hour a day to confirm function and insure its availability in the event of an emergency.


How can I tell if my GAC products are authentic?

Authentic GAC products are made in the U.S.A.   As a highly respected provider of engine control systems, GAC products are often counterfeited and come mostly out of China. GAC prides itself on high standards and takes protection of its "Made in the USA" brand very seriously, practicing vigorous quality measures to ensure that its products are certified by all major standards.  Made with poor quality, counterfeits will likely have a number of shortcomings and are therefore unreliable. These shortcomings will interfere with the operation of an entire engine system and can cause serious damage.  Ultimately, the best way to verify the authenticity of your product is to contact GAC with your serial number by calling 1-413-233-1888 or emailing  However, here are a few things for which to look when spotting a counterfeited GAC product.


Confirm Your Serial Number at 

or Call 1-413-233-1888

TIP OF THE MONTH: Did you know the ESD5xxx series is marine certified? 



GAC will be closed Monday, February 18th for Presidents' Day