What is a Diesel Generator?
A generator, also known as an electric generator, is a machine that converts mechanical power into electricity. A diesel generator is simply a machine that uses diesel to produce motion for a generator, which is then converted to electrical energy with the help of an alternator.
Diesel Generators are most often used outdoors, in places where there is no access to a power grid with electricity. Diesel Generators can also be used as a backup power supply for critical situations where power is needed, in case power grids fail.
How do Diesel Generators Work?
- Diesel Generator Engine burns diesel to produce motion(mechanical energy) for the generator.
- Inside the generator, there are wire coils. The mechanical energy induces the movement of electric charges inside these wire coils. This movement of electric charges produces electricity.
Usually, these wire coils are made of copper, as copper can carry more current as compared to other materials like Aluminium, for the same length of wire.
How to choose a Diesel Generator for your needs?
- Voltage and Frequency of Load
The first thing you need to look at before choosing a diesel generator are some basic parameters such as the voltage and frequency your load requires. This usually doesn’t vary much, with loads usually requiring 400-415V (Singapore) or 440-460V and frequency of 50Hz (Singapore) or 60 Hz. Some loads can even function in both these frequencies and voltages, but it is always good to check as you don’t want to end up buying a generator that you cannot even use!
- Current Consumption of Load
Now that you have got your basic parameters covered, the next thing you need to look at is the current your load will draw.Once you have your load current consumption, you can start calculating the minimum KVA of the generator you would require.
Minimum KVA = (V x I x P.F.)/1000
Where V is the Voltage of the Load,
I is the Current Consumption of the Load,
& P.F. refers to the Power Factor of the Load
Power Factor = 1 for Single Phase Generators
Power Factor = 1.73 for 3 Phase Generators
However, the recommended kva for your generator will be different from the minimum KVA your generator needs.
We recommend getting a generator that can supply 25% more current than the current your load needs for ordinary loads.
Recommended KVA (Ordinary Load) = (1.25 x V x I x P.F.)/1000
This is mainly for 2 reasons.
- Your loads requires 100 Ampere of Current now. 3 Months later, you may want to temporarily increase your loads, where they require 120 Ampere of Current. If you did not add in a buffer to the current your generator can supply, you will have to spend a lot more money buying a whole new generator to supply this additional current temporarily.
- Generators are not supposed to be operated at full capacity all the time. In fact, this is the case for all equipment’s and machines. Take a car for example. Imagine driving your car on rough ground, day after day. It will be able to drive on rough ground for a day, for a week even, but eventually your car will run into wear and tear pretty quickly, faster than if you did not push it to its limits.
For special loads, such as motors, which tend to consume up to 6x the current to get them started, the recommended KVA of the generator you need to get will be vastly different. If the motor load requires 6X current consumption(E.g. 600 Ampere instead on 100 Ampere) only during the first 5-10 seconds, you would be recommended to at least get a generator that can supply 3X of the regular current consumption of the 100 Ampere load (300 Ampere instead of 100 Ampere). This initial 5-10 second surge of 600 Ampere current can still be provided by a Generator that can typically only supply 300 Ampere Current.If the starting 600 Ampere current consumption is required by the motor for significantly more than 5-10 seconds, say for a minute or two, you will have no choice but to opt for a generator that can permanently supply 600 Ampere current.
Recommended KVA (Motor Load: 5-10 Second Current Consumption Surge of 6 X Normal Current)
(6 x V x I x P.F.)/(1000 x 2)
Recommended KVA (Motor Load: Current Consumption Surge of 6 X Normal Current for longer period of time)
(6 x V x I x P.F.)/1000
- Type of Load
Depending on the type of load you wish to supply current for, the type of generator recommended would also be different. For example, single phase generators are recommended for certain types of loads, whereas 3 phase generators are recommended for others.
Single Phase Generators vs 3 Phase Generators
Single Phase Generators have only one output to supply current.
Three Phase Generators have 3 outputs to supply current, and as such can withstand a much higher power output than single phase generators.That is why all generators above 20 KVA are usually three phase generators.The biggest advantage of 3 phase generators are that they can not only work with 3 phase loads, but also with single phase loads.
Single phase generators only work with Single Phase Loads.
For operating motors and loads with higher electricity consumption, usually, 3 Phase Generators would be required!
- Size of generator
Usually, the bigger the current output of the generator, the larger it will be. However, if you are still looking for a diesel generator that is small and portable compared to others, what you can do is compare the sizes and weights of generators within the same range of power output (KVA). This will help you select the smallest generator for the power output you need!
- Budget for generator
You need a generator to work smoothly and efficiently without excess fuel consumption and defaults, every time you turn it on. Otherwise, your purchase would be nothing but a waste. So buying an unknown or new brand in the market may save you a few dollars, but can potentially give you an operational nightmare. Going with proven generator manufacturers, like Denyo, Airman and Weldman who have been tested for years and have a proven track record will help you avoid a lot of pain in the long run.
Diesel Generator Maintenance and Repair
Here are the repair guidelines we offer our clients:
Here are some maintenance guidelines we advise all our clients to stick to.
For trouble free operations, follow the duty cycle of the generator
Do not overload or operate the generator without rest at maximum capacity