The Reason for The Low Engine Operating Speed of Diesel Generators

Why does the engine run slightly at rated speed and frequency?

There are several reasons why the engine may run slightly at rated speed. The answer depends on the type of adjustment installed. For engines on generators that are not connected in parallel with other generators or power sources, this is true. For generators connected in parallel with the main power supply or other devices, this clause applies when the device is unloaded.

The engine equipped with a mechanical governor needs to be adjusted to operate at a higher fixed speed.

An engine equipped with a manual governor can usually be adjusted to a higher fixed speed. For examples of speed changes in mechanical speed controllers, please contact Dingbo Electric.

Remember to use a mechanical speed controller with a descent, and the no-load speed should be 3% -5% higher than the rated speed, in order to reach the rated speed for application after the speed drops.

Engine electronic governor or ECU

The speed setting may require programming

For engines equipped with electronic speed controllers, it may be necessary to program the speed correctly. Electronic speed controllers typically have a set value called "rated speed", "nominal speed", or similar as their speed control target. This usually only needs to be done during initial setup, usually by the engine manufacturer. Without engine manufacturers or their agents, it may not be possible to set the rated speed as they typically do not release software to the public.

Speed control input requests lower speeds.

For engines equipped with electronic speed controllers or ECUs, especially generators operating in parallel with other generators or power sources in synchronous systems, they will have a speed input that allows the generator controller to adjust the speed. If the engine governor is in, this is true descent or synchronization mode.

Typically, this input is a 0-5V or 0-10V input from the generator controller to the engine governor or ECU. You should use the engine and controller wiring diagrams to check the circuit and inquire if the reference voltage at the engine terminals is correct.

On a typical generator, a synchronous unit is usually equipped with a DSE8610MK2. Using this controller, the engine speed control can execute CANBUS links downwards or upwards for engine electronic governors with the following components, or with electronic control units installed or output terminals 35/36 through the governor.

For engines with an output of 0-5V, it is necessary to operate at the rated speed, and there should be a 2.5VDC output reaching the engine terminals between 35/36. For most engines, if the voltage output is low or zero, the speed will be very low. If the output is high, the speed will also be high.

For an engine with a 0-10V output, it should run at rated speed and there should be a 5VDC output reaching the engine terminals between 35/36. For most engines, if the voltage output is low or zero, the speed will be very low. If the output is high, the speed will also be high.

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