The mechanism and introduction of generator

The mechanism and introduction of generator

There are many ways to generate electricity, but the most suitable generator for emergency use is one that uses an internal combustion engine as power because it is versatile and easy to start.
Here, we will briefly introduce the mechanism of generators, focusing on two types of internal combustion engine generators, diesel generators and gas generators.

Features of diesel generators

As the name suggests, it is a generator with a diesel engine as the main engine, and it is the most popular standard generator at present.
Especially for industrial generators, high-torque marine engines are mostly used.
Since the power demand fluctuates constantly, it can output stable power for the load, so it is not easy to trip. Thanks to its sturdy construction, it can be used for a long time, making it a valuable asset.

Features of Gas Generators

These engines are based on marine diesel engines and run on natural gas or other fuels with a lower environmental impact. The exhaust gas is clean, low particle, and does not emit sulfur oxides. Currently, we are working hard to deal with the diversification of fuels such as liquefied petroleum gas, volcanic gas, and methane fermentation gas. It is quieter, has less vibration, and can source fuel at a lower cost than a diesel engine.
Installation location Due to air pollution regulations, local ordinances restrict the use of diesel generators fueled by light oil. In this case, there is no choice but to use a gas engine or gas turbine generator.

Generator system

Whether it is diesel or gasoline, the kinetic energy obtained by the engine needs to be converted into electricity. The alternator is at its heart.
In other words, what is commonly referred to as a generator can be said to be a set of power engines that generate kinetic energy and an alternator that converts the kinetic energy into electrical energy.


Generator Type and Selection

Influence of power generation speed and load

The number of revolutions of the generator is the frequency. The frequencies of 50 and 60 Hz are directly related to engine speed. In other words, a constant number of revolutions must be maintained while taking any load. Frequency fluctuations can cause fatal damage to equipment that uses electricity.

Engine characteristics are important for power generation

If the generator doesn’t use electricity, it doesn’t generate electricity. Whenever there is demand, it generates power, putting pressure on the engine and vice versa. This instantaneous fuel adjustment is used to maintain a certain number of revolutions, but if you compare it to a car, it’s akin to going up and down a steep hill at the same speed. However, car engines obviously cannot withstand such a sudden heavy load.

There are two types of diesel engines

Generator engines are mainly divided into truck engines and marine engines.
[Truck engine] Using a
truck engine, a cheap generator can be made, but since it is an engine that increases the RPM output, the torque as a generator is poor.
[Marine engine] attaches great importance to torque
, which is why marine engines with large torque appear, and marine engines that maintain a constant speed for a long time can be said to be engines for generators. Extremely demanding engine characteristics that do not allow rotational speed fluctuations play an important role for the generator to respond to rapidly fluctuating power demands. Although it costs several times as much as a truck engine, it is highly reliable and of course the asset value.


When choosing a model, the load factor of the power used is important.

The driving force of the generator is the engine. What happens if you continue to step on the 1st gear in the car?
It is important to effectively set usage times and load factors and choose a model sized to match them.
If the power supply destination of the generator has a motor with a large starting current, it is necessary to understand its characteristics first. Motor starting methods include direct injection, up to 7 expansions, reactor start, slow start and inverter start.
Calculate the required power based on these facility specifications and calculate the total amount of power required.
Next is the time to use the generator for power, but the size of the generator will vary depending on whether it’s for emergency or regular use.
Emergency for several hours per day = Load factor up to 70-80% of generator rated output.
Continuous operation for 8 to 24 hours or more with normal use = 50 to 70% output or less.
That is, to choose a large industrial generator that is often used.
If you can provide us with a single wire connection diagram and equipment specifications, we can provide consulting services. Please contact us.


Use of generator

  • [Backup] In case of power failure (emergency)

■Equipped to provide power as insurance in the event of an emergency when the commercial power supply is cut off. To avoid short-term power outages, we run for a few hours a day.
■ There are various startup methods, such as manual and automatic. It takes tens of seconds to start the generator.
■Uninterrupted connection requires a UPS (large battery) to supply power while the generator is running.


  • Reduce contract power [peak clipping]

■The annual contract fee for the next year is the amount when the usage is the highest in that year.
■As we supply some electric power from generator when there is much electricity consumption, we hold down the annual use maximum.
■It is necessary to have a careful discussion with the person in charge of electricity according to the needs of the customer. First, we recommend that you consult a chief electrical engineer familiar with the requirements.
Electricity fee in the same month of the previous year ÷ (electricity fee in the same month of this year (output kilowatts × operating hours × planned operating days × unit price of electricity in the current year)) × 100% = reduction rate


  • [Power Plant] for the purpose of selling electricity

■If fuels such as self-gas and biofuels can be secured at low cost, profit can be made by selling electricity. However, there are the following problems.
■ Stability of fuel composition and flow
■ Whether there is a manufacturer’s guarantee based on composition ■
Unclear power purchase price factor


  • [Constant power supply] For the purpose of constant power supply

■ A device that is always powered by a generator.
■Continuously generating electricity through a gas engine with low operating cost, it is possible to provide electricity when it is difficult for the power company to supply it.
■Provide stable power supply for long-term power outages.

The introduction of generators is a comprehensive engineering process involving various elements. However, not everyone has the basic knowledge of generators.
Industrial generators are not ready-to-use devices like portable generators.

When selecting equipment, we determine the capacity and voltage of the generator based on the characteristics of demand changes and target properties. It is important to investigate the characteristics of consumers including them.


Government application before installation

Submit to the Ministry of Economy, Trade and Industry and the fire department having jurisdiction over the installation site.
Frequent use, emergency use. Procedures and details vary depending on whether the facility is a soot-generating facility or not.
Depending on the combustion capacity (fuel consumption per hour) of the generator, the diesel engine has a heavy oil equivalent of 50 L/hr or more, and the gas engine has a capacity of 35 L/hr or more
. , you will need to submit the following:
・Construction Plan Declaration Form
・Fume and Fume Explanation ・
Notice of Changes to Safety Regulations
For generators that do not fall under the category of fume generating facilities, only a Notice of Changes to Safety Regulations is required.
For conventional generators, the fuel use plan should be added to the smog statement.

Generator installation notice is required for local fire department procedures.
For diesel engines, depending on tank size and fuel type, a Small Hazmat Storage Disposal Notice may be required.
According to the notice, details such as the setting (see photo), capacity, accessories, etc. of the oil embankment vary by local government, so it is necessary to consult with the local fire department where the generator will be installed.


Installation and construction

The installation of private generators requires compliance with fire and building standards laws because of the storage of large amounts of noise, vibration, exhaust gas and combustible fuels.
Municipal ordinances may apply to target buildings.
There are standards for distance from buildings and generator boxes (cabinet) for outdoor installations, so it needs to be discussed carefully with the local government and local fire department where the generators will be installed.
You can rest assured that our generator department will assist you with all of these procedures.

So if you have any problems and interests in any diesel generator, please feel relax and contact us PowerSUM.