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How to correctly size electric power generators?


How to correctly size electric power generators?

Before purchasing a generator set, it is necessary to define what will be the purpose of this equipment and for what purposes it will be used, in addition to evaluating the energy capacity needed for both the generator and the machines that will be connected to it.

This information is part of the sizing of generators, a fundamental element to ensure the durability and efficiency of the generator set, avoiding possible waste of fuel and energy consumption.

But do you know how to scale electric power generator? If the answer is no, read on and learn how to do it correctly.

Where to start sizing power generators?

You already know that, regardless of the energy demand and power needed, for the generator set to have high profitability and contribute to a reduction in consumption, you need to be careful, right? The same goes for generator sizing.

The type of load, period of operation, form of use and storage location are the main points to be analyzed when elaborating the dimension of electric energy generators.

In addition to these characteristics, it is also necessary to calculate the power of the generator set. However, there are some factors that must be taken into account, such as observing whether your consumption is of an emergency or essential nature.

The emergency type, for example, it is necessary to distinguish between essential and non-essential consumers because, depending on the case, you can opt for a smaller generator.

In conditions where electricity is used constantly and has a greater demand on consumption, the use of more robust and higher-powered generator sets (diesel generators) is recommended.

In order to know the ideal genset power, you must sum the electrical energy consumption index in watts (W) of all objects that will be connected alone or simultaneously to the device.

The result of this sum corresponds to the total energy that the generator set must produce. When calculating, it is recommended to establish 25% power surplus in relation to the required value, for safety reasons.

The calculation is done as follows:

Power (W) = voltage (volts) x current (I)

When performing the calculation, you can consider 1CV = 750 W and 1000 W = 1KVa

Another important tip is to check the operating power (Watt) of the boards of the equipment that will be connected to the generator, which contains information needed to make the correct dimension.

Among them, we highlight:

  • Rated current (In)
  • Engine power (CV)
  • Ratio between inrush and rated currents (Ip/In)
  • Rated voltage (V)

In inductive devices (those that have a motor to operate), the power value must be multiplied by 4 due to the energy peak that such equipment reaches when activated.

Therefore, this estimate must be remembered when the power value is calculated as, in this way, it will be possible to obtain the exact total of the required energy capacity.

As for those considered  (electric shower, television and heaters), the nominal peak value does not change.

Below is an example of how to dimension electric power generators:
Fuel station

  • 2 pumps x 3 motors x 1 hp = 4,500W normal use/18,000W peak
  • 6 90W LED lamps on the track = 540W normal use
  • 1 computer for track = 800W normal use
  • 1 computer for the store = 800W
  • 1 Freezer = 700W normal use/2800W peak
  • 4 60W LED store lamps = 240W normal use

Total = 7,589 W / 23,180 at Peak

Therefore, the minimum value of the generator would be 8 KVA, being at the peak start, 23,000W.

What are the consequences of not sizing electric power generators?
If the dimension step is ignored, it can lead to overheating of the generator set, high consumption of lubricating oil and an increase in the smoke produced, impairing the performance of both the generator and the appliances connected to it. For Generator You can read this comparison

And to do the dimension correctly, look for an electrical technician. He is the professional indicated to identify the necessary energy demand of the generator set, in addition to making its installation in a safe way.

As we have seen, sizing electric power generators is a fundamental element for equipment operations to continue with excellent performance.