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July 22, 2022


Many people think Diesel Generator Sets are noisy and create a lot of vibrations, but this is not true. Modern Diesel Generator Sets have an acoustically designed enclosure, and a good foundation to minimize the noise and vibration to a great extent. This article explains to you about the working of a Diesel Generator Set (D G Set in short) and some useful tips to help you buy it.  


How do industrial and commercial Diesel Generator Sets work?

A Diesel Generator Set consists of a diesel engine coupled to an alternator, and there are many other parts and controls for its smooth and efficient working. It has control and display systems to caution the operator on fuel position and performance parameters to run the Diesel Generator Set efficiently. The Diesel Generator Sets used in industrial and commercial sectors are of high KVA capacity and produce three-phase power.

You can use a Diesel Generator Set as a primary source of power if the place does not have the facility of grid power or as a standby unit (for use during the power blackout).

Present-day Diesel Generator Sets have the capability of ensuring automatic transfer of the source of power from the power grid to the Diesel Generator set when there is a grid failure.


Working of a Diesel Generator Set with an automatic transfer switch (ATS)

Industrial and commercial units have a transformer installed on their premises and the transformer receives the high tension (HT) power supply. The transformer converts the HT power to low tension (LT) power and the LT power flows into the ATS (automatic transfer switch). From ATS the power flows into the distribution panel and is distributed to the equipment, lighting, computers, etc.

The Diesel Generator Sets are designed to continuously monitor the supply of electrical current and start automatically when there is a grid power failure and stop when the grid power is restored. The lever of the ATS can shift between the transformer and the DG Set.

Hubei Junvoch Industrial & Trade Co., Ltd 

Let us see what happens when there is a grid failure and there is no power supply to the ATS?

The ATS has a current sensor, and this sensor senses that there is no supply from the power grid and automatically connects the “transfer switch” with the Diesel Generator Set.

The Diesel Generator Set also has a current sensor and as soon as the ATS is connected to it, the current sensor senses this and starts the Diesel Generator Set. This process ensures there is a negligible interruption of the power supply. The connection of the ATS shifts automatically from the power grid to the Diesel Generator Set.


Then, what happens when the supply from the power grid is restored

The current sensor on the ATS senses the restoration of the supply from the power grid and automatically shifts from the Diesel Generator Set to the power grid. The current sensor on the Diesel Generator Set also senses this and it stops working. However, the Diesel Generator Set may run for a few minutes more to get it cooled down.

If you choose to buy a Diesel Generator Set with a manual transfer switch (instead of an ATS), then in the event of a blackout the shifting of the “transfer switch connection” from grid power to the Diesel Generator Set and vice-versa has to be done manually. There will be a gap between a blackout and the resumption of power from the Diesel Generator Set.


Advantages of Diesel Generator sets.

· The Diesel Generator Sets have a superior response rate (about 10 seconds) and make it almost instantaneous.

· The diesel engine works on compression ignition and does not need spark plugs. This reduces the maintenance to a good extent.

· A well-maintained Diesel generator Set has a product life of 15 years or more.

· The fuel efficiency of a Diesel Generator Set is superior.

· You can use a Diesel Generator Set continuously for a longer period compared to other generators.

· If you are located in an area that is prone to frequent grid power failure, Diesel Generator Sets are the best option.

· Diesel has a better shelf life, gives more power per unit of fuel, and is less volatile compared to natural gas or gasoline.

· In case of a natural disaster like an earthquake, or hurricane, the Diesel Generator Set continues to work since the supply of diesel is normally not disrupted.

· The major competition for Diesel Generator Set comes from the generator that is coupled with a natural gas run engine. Natural gas burns cleaner compared to diesel and hence it is considered environmentally friendly. However, when it comes to high KVA generators, Diesel Generator Sets stand superior.


Buying guide for Diesel Generator Sets.

If you intend to buy a Diesel Generator Set for your industry or commercial business, go through the following steps.

Step 1- Diesel Generator Sets are classified based on their power output in KVA (kilo volt-amperes), so your first task is to calculate the maximum demand load in KVA for your industry or commercial business.

· Make a list of all the machinery, equipment, lighting, lifts, computers, motors, pumps, and all other units that run on electric power and note down their kilowatt (KW) requirement. Adding up all these will give you a total connected load. Let us say your total connected load is 1000 kW. (If you want to run only a few selected units during a blackout, calculate the connected load for those units only).

·Add 10% for future addition of equipment. The total connected load is revised to 1000 KW+10%=1100 KW.

· All the equipment, machinery, and other units are not connected to the load for all 24 hours. For example, you do not use lights during the day. This is expressed as a demand factor, and it can be 80% for a commercial business and 80 to 90% for the industry. Let us assume 80% for our case. So, the maximum demand load is 80% of the total connected load. The maximum demand load is 80% of 1100 KW= 880 KW.

· Convert this maximum demand load from KW to KVA by using the power factor. Assume the power factor as 0.8. So maximum demand in KVA is 880 ÷0.8=1100 KVA.

· Since a Diesel Generator Set does not run with 100% efficiency, you have to consider this as a factor for calculating the final demand load. Assume the efficiency of the Diesel Generator Set as 85%.  The maximum demand load (considering generator efficiency) is 1100 ÷0.85=1294 KVA.


You need a Diesel Generator Set with a capacity of 1294 KVA or more (do not select a Diesel Generator Set of less than 1294 KVA).

Step 2- You can select either one Diesel Generator Set for full capacity or a combination of two Small Diesel Generator Sets. Consider your needs and make a decision. Your hint here is Diesel Generator Set has the best fuel efficiency when run at 80% load (it should be run with 50% or more load to keep the fuel efficiency fairly good).

Step 3- ATS system or manual transfer switch system, make a decision.

Step 4- Decide the location for the Diesel Generator Set for its best performance.

Step 5-Make a study of different Diesel Generator Sets. Verify about the brand reputation, their service support in your area, and the availability of engineers and spare parts near you, before you finalize on a brand. The life of a Diesel Generator Set is 15 years or more and the 24×7 service support of the dealer and manufacturer is very important.

Step 6- Obtain the calculation of running cost and maintenance cost for all the brands of Diesel Generator Sets that are under your consideration and compare them. This is an important comparison and helps you to decide on a good and economical brand of Diesel Generator Set.

Step 7- Machines and motors need a higher KW during starting. Discuss this with the dealer or manufacturer of the Diesel Generator Set.

Step 8- Based on the above data, discuss with your team, make your decision, and select a brand of Diesel Generator Set that meets all your requirement.

Step 9- Do not buy the Diesel Generator Set in advance, it will get deteriorated in storage. Plan and schedule its delivery just when you need it.

Step 10- Purchase only from the manufacturer or their authorized dealer.

Want to learn more about a Diesel Generator set? Please go through our article “Diesel Generator Sets and their applications”.

Hubei Junvoch Industrial & Trade Co., Ltd


· Hubei Junvoch Industrial & Trade Co. Ltd. is a professional company located in the People’s Republic of China and its products include Diesel Generator Sets, Engine assembly, and Engine parts.

·JUNVOCH has created a long-term strategic partnership with internationally renowned engine manufacturers such as Cummins, Perkins, Doosan, Shanghai Mitsubishi, and alternator manufacturers such as Leroy Somer, Stamford, and some Chinese famous engine manufacturers as well

· JUNVOCH considers Integrity, Dedication, Unity, and Win-win as the core values, and their service strategy is " Focus on customer focus, Meet or exceed customer expectations, Innovation service mode, and Improve service levels."

· JUNVOCH has a wide range of Diesel Generator Sets up to 2500 KVA.

· For further information please visit or contact at Tel: +86 -27 -6712 7626 and Email: