Got a generator speed problem? Having problems connecting a generator to the load (items you are trying to power), this article might help you. All generators, petrol and diesel, small and large show the same common issues. Learn more in this article.
What is generator low frequency?
Generator frequency is the number of electrical cycles per second, measured in Hertz (Hz) and this is directly proportional to the engine speed. So if the frequency goes down, it is due to the engine speed. If the generator frequency is going down, but the engine speed is constant its a different problem. You can tell as you can hear an engines speed change.
Why would my generators engine speed go down?
When you apply load to a generator it will always have an effect on the speed (although if the load is small, it might be a small effect). Normally, it will recover in less than a few seconds.
When I apply load my generator slows down or just stops?
In cases where the load is too large the speed will not return to its normal level, or the generators engine will stall and shutdown entirely. The power a generator can provide is limited by the amount of fuel and air that can be injected into the cylinders for combustion. A 10kW (ESP rating) generator can only use enough fuel to produce 10kW of power (plus a little bit for speed governing usually.) If you try and apply 12kW, it can't combust enough fuel, the speed will start to drop and the engine could stall. This is called overloading the generator.
Some generators, have protection for overload. Overload protection works when the generator is not big enough for the items you are trying to connect to it. For example, if you have a 10kW generator with overload protection and try and connect 11kW, the generators control panel, or engines ECM will shut down the engine and display a warning on the control panel.
I'm not overloading my generator - what else could it be?
A fuel restriction or air restriction would also cause this problem, try changing your fuel filter and your air filter to see if this helps. You could also have poor quality fuel - if your fuel is old (especially petrol) or has been contaminated it won't be providing the same amount of power per litre, so you will end up with an under powered generator.
There are of course many reasons that a diesel generator can shut down, so this is just one answer to why it might be happening. If the generator only shuts down when you apply the load and connect it to the devices you want to power, then overload is a strong possibility.
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