Speed Governor & Actuator

Diesel generator speed governor currently in use

(The Brands mentioned here are for reference purpose only, our parts can exactly replace the original ones.)

Generator Speed Governor: 

Kutai: EG2000, EG3000

Fortrust Series : C1000A, C1000B, C1002, C1500B, C2001, C2002

YUNYI Series: ESD6000, ESC8000, ESS9000, ESC9800

Other Speed Governors: S6700E, S6700H

Cummins: 3044196, 3062322, 3098693, 3037359, 4914090, 4914091, 4913988, 3044195, 3032733, 3062323, 3036453, 3053065, 3030256, 3053060

GAC Sereis: ESD2210-12V, ESD2210-24V, ESD5111, ESD5221, ESD5500E, ESD5522E, ESD5550E, ESD5570E, ESD5330, LSM672N, SYC6714


The Speed Controller is an important component of the diesel generator set. It can automatically adjust the oil supply according to the change of the load of the unit, so as to ensure the diesel generator genset to work stably within the specified speed range. Generally, when the diesel generator set is working, the load will often change greatly. If the oil supply is not adjusted in time, the generator may have a accident. In the work of the diesel generator set, condition of frequent load changes, it is impossible to rely on the operator to adjust the oil supply and maintain a stable speed, so the governor must be installed.

According to different working principles, generator speed controller can be divided into mechanical governors and electronic governors. In the mid-1970s, mechanical hydraulic generator speed controller were widely used in generator sets or marine diesel engines powered by diesel engines or gas engines. With the need of energy saving, it is obvious that the traditional mechanical hydraulic governor on the market at that time can no longer meet the market regulation requirements. The electronic governor can automatically increase or decrease the fuel supply in the fuel injection pump according to the change of diesel engine load, so that the diesel engine can run at a stable speed.

1. Function Of Speed Controller

Cummins diesel generator governor is used to keep the speed of diesel engine stable. Its speed will change correspondingly in the process of load change of diesel engine. When the speed decreases, if the governor does not adjust, the diesel engine will eventually stop; When the speed increases, if the governor does not work, the diesel engine will eventually be unable to withstand excessive centrifugal force and damage. The function of the governor is to keep the speed of the diesel engine stable. In addition, the governor can also maintain the minimum and maximum speed of the diesel engine to prevent flameout during low speed operation and “runaway” during high speed operation, resulting in mechanical damage.

2. Composition Of Generator Speed Controller

The governor is composed of speed sensing element, control mechanism and actuator. The speed sensing elements are two speed sensors distributed at the free end of the diesel engine; The control mechanism is two “black boxes” distributed on the body of the diesel engine near the generator side. The two sets of control mechanisms are standby for each other. When one set of control mechanism fails, it will automatically switch to the other; The actuator is distributed at the free end of the diesel engine and the upper part of the speed sensor, and its internal pipeline is connected with a pipeline of the diesel engine lubricating oil system for power.

3. Basic principle of governor

Basic principle of speed regulation: changing the amount of diesel entering the cylinder for combustion (increasing or decreasing the “throttle”) can change the speed or load of the diesel engine. If the speed is kept constant, changing the amount of fuel can change the load of Cummins generator; If you keep the load of the diesel generator unchanged and change the amount of fuel, you can change the speed of the diesel engine. The governor changes (or adapts) the load of the diesel generator while keeping the speed unchanged.

4. Speed regulation process

First, the speed change is sensed by the speed detection element, and then transmitted to the speed control mechanism. Compared with the set speed value, the positive and negative of the difference will determine whether to turn down or turn up the “throttle”. The difference signal (electrical signal) is transmitted to the actuator, in which the pressure of the lubricating oil system is amplified (hydraulic adjustment) to drive the “throttle” to open or close.

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