Sizing A Generator – Determining What Size Generator You Need

Buying a generator that can handle your power requirements is the most critical aspect of the purchasing decision

Whether you’re interested in prime or standby power, if your new diesel generator can’t meet your specific requirements then it simply won’t be doing anyone any good because it can put unnecessary stress on the unit and even damage some of the devices connected to it. Unfortunately, figuring out exactly what size of generator you require is often very difficult and involves a number of factors and considerations.

Making a choice amongst single phase, three-phase, KW, KVA, welder, standby or motor starting generators can be absolutely mind-boggling. To prevent such confusion, we’ve decided to write this blog; to help you get a better idea of how the sizing process works and give you some key things to keep in mind. This is not a substitute for a certified electrician, however, which we always suggest talking to before buying, but it should provide you with enough information to get a solid understanding of some of the key things that are involved when choosing a generator.

With the latest advancements in the field of electrical engineering, generators are now available in a wide range of sizes. Generators with power supply capacities of 5 KW to 50 KW are readily available in the personal and home use markets, while industrial generators are anywhere from 50 KW to over 3 Megawatts.

Handy and portable gensets are available for homes, RVs and small offices, but larger businesses, data centres, buildings, plants, and industrial applications need to use the much larger sized industrial generators to meet their higher power requirements.

Many people believe smaller generators can be used for standby electric power, because they are not running all the time. Not only is this a myth, it can be very detrimental to your generator. Unfortunately, generator under-sizing is one of the most common mistakes committed by buyers.

Not only does it involve the risks of damaging your new asset; it can also damage other assets connected to it, create hazardous situations and even limit the overall productivity of the business/person relying on it. If nothing else, the key thing to remember here is that more is always better than less.

While there is no substitute for having a certified electrician perform an inspection and calculate everything for you, the guidelines below do offer some great starting points and should at least get you started in the right direction:

Know Your Requirements: Going to a dealer and buying the best or cheapest generator available without any other consideration is definitely not the best approach. It is always better to delve deep into your power generation requirements before making a choice. You can do this in the following ways:

• Make a list of the items that need to be powered by the generator
• Make a note of the starting and running wattage of the respective items
• Calculate the total power requirements in KVA or KW

How to Find the Starting and Running Wattage: Getting the right starting and running wattage of the devices you intend to power is crucial for calculating the accurate power requirements. Normally, you will find these in the identification plate or the owner’s manual in the buyer’s kit of each respective device, tool, appliance, or other electrical equipment.

Ampere – Watt Conversion: You may often find power requirements of tools stated in amperes. In order to convert the power requirement of a tool from ampere to watts, follow these calculations, or you can also use our handy conversion tool on our power calculator web page.

If you require additional information on how to properly size a generator to meet your exact needs and requirements, you can give our expert team a call on 01429 264 097. Alternatively, you can fill out the contact form here.