Mechanical & Motion Systems

Problem Solved: Generator Set Gets an Actuator and Speed Control Boost

Sept. 22, 2022

Machine Design welcomes submissions on how to solve a specific engineering or technical problem. In the following article, an actuator/speed control recommendation improves reliability in a generator set and power unit.

Pam Palm

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The Problem: The extraction and processing of oil and gas is dirty work, performed 24 hours a day, seven days a week in extreme conditions. The machines that make this happen have to be reliable and ready to work no matter the weather, as demand for oil and gas is constant around the world.

More than two decades ago, SES Arrow, a manufacturer of oilfield equipment including generator sets and power units, contacted GAC, a manufacturer of engine control products, based on a recommendation from Arrow Engine, for whom SES Arrow is a master distributor. They were looking for a solution for their SES90 Gen Set and Power Unit. The gen set is used in oil fields as a running generator that powers various equipment, including lights and pumps that remove water in the oil extraction process.

The Solution: SES Arrow paired GAC’s ATB T2 Series Integrated Actuator/Throttle Body 45 mm and 65 mm with the GAC’s ESD5131 and ESD2241 speed control units. The actuator controls the flow of fuel into the engine similar to the gas pedal in a car. The speed control units, which are also called governors, control the throttle position of the engine, opening or closing it depending on the speed and stress on the engine. This maintains whatever speed is put into the speed controller, similar to cruise control in a car.

The ESD5131 and ESD2241 allow for PID tuning for optimum transient load response. For those unfamiliar, PID is an algorithm for speed control consisting of proportional, integral and derivative controls. Proportional, also known as gain, sets the throttle to a constant speed when not under a load, so essentially when the engine is running but not under strain.

Integral, also known as stability, is how quickly the engine is brought back to speed after strain is put on it. And derivative, also known as deadtime, is a temporary correction to compensate for overshoot lags of other disturbances. Proportional and integral are the two main settings, with derivative being used in finicky engines or when there is a random issue.

GAC speed controls boast a speed accuracy of ±.25%, meaning they have extreme reliability for keeping an engine right where it needs to be. The GAC actuators and speed control units inside the gen set and power unit allow it to run more efficiently, keeping the engine on track and running smoothly.

This article was submitted by Governors America Corp. (GAC). Pam Palm is a technical writer who writes about hardware solutions for engineering and manufacturing companies throughout the United States.

Machine Design accepts editorial submissions on how to solve specific design, engineering and technical problems. Submit your article query to [email protected].