The Relationship between Frequency and Speed of Diesel Generator Set

In our daily lives, with the popularization of electricity, generator sets, as a type of power generation equipment, have also been widely used. However, in the use of generators, we often encounter situations where the generator malfunctions. For example, what should we do if the frequency of a diesel generator set is too low? This requires us to deepen our understanding of the frequency and rotational speed of generator sets. To enable everyone to learn more about the frequency and rotational speed of diesel generator sets, the following is an introduction by Guangxi Dingbo Power, a diesel generator manufacturer.

The frequency and rotational speed of diesel generator sets are closely related. The following is a detailed explanation of the relationship between the two:

1.Currently, there are two standard definitions of frequency globally: 50HZ and 60HZ. They represent the number of positive and negative polarity changes of alternating current per second. As we all know, frequency is related to rotational speed. So, is rotational speed the only factor that affects frequency?

2.Let's take a look at the frequency calculation formula: F = number of pole pairs × rotational speed / 60. Take a diesel generator set as an example. If the number of pole pairs is 2 and the engine rotational speed is 1500 revolutions per minute, then the frequency F = 2 × 1500 / 60 = 50 Hertz. For a domestic steam turbine generator, the number of pole pairs is 1, and the rotational speed of the generator set is 3000 revolutions per minute. Therefore, the frequency is F = 1 × 3000 / 60 = 50HZ.

3.Speaking of this, let's extend the discussion. If a customer needs a 60HZ diesel generator set, how can we achieve this? The number of pole pairs of a diesel generator set is the same. To achieve 60HZ, the only factor we can change is the rotational speed. N = F × 60 / 2 = 60 × 60 / 2 = 1800 revolutions per minute. That is to say, if a customer needs to customize a 60HZ diesel generator set, the rotational speed of the generator set must reach 1800 revolutions per minute.

4.Once the number of pole pairs of a diesel generator set is determined, to ensure a stable frequency, the generator set must operate at a constant rotational speed. To prevent the diesel generator set from having uneven rotational angular velocity of the generator due to torque pulsation, which causes voltage fluctuations and flickering lights, the rotor of the diesel generator is also required to have a large moment of inertia. Moreover, the natural torsional vibration frequency of the shaft system should differ by more than 20% from the frequency of any alternating component in the torque pulsation of the diesel engine to avoid resonance and shaft breakage accidents.

Dingbo Power was founded in 1974 and is one of the earliest manufacturers of generators and diesel generator sets in China. If you want get more information, please feel free to send email to [email protected] we will pay highly attention on your question.