Your Guide to Generator Sizing

We’re talking about generator sizing in this post, we hope you find it helpful. Size is important when it comes to generators for hire and this is because your power will be affected if you oversize or undersize one. We’ll talk about some basics here today but if you’re confused you can always give us a call because we’re always here to help.

Load - what’s going to be needing power to use your generator?

Add up all of the wattage. The total will give you the amount of electrical power that your equipment will use and you can then work out the minimum power you need from a generator. This helps enormously in hiring the right one.

Wattage - where to find?

Electrical equipment will normally have the wattage somewhere on it, this could be on the nameplate, or in the manufacturer’s guide you get with your appliance when you buy it.

Starting and running - what’s the difference?

Some equipment will have different running and starting wattage. It can take more energy than you’d think to start something up with an electrical motor than while it’s actually running. Electrical surges need to be figured in therefore into the size of the generator you’ll be using.

Something a little tricky perhaps - you’ll need to convert kW to kVA.

When you work out your power needs by adding up the wattage, you’ll find that it gives you the results in kilowatts, because this is what’s used to measure the actual power by the load to produce the output.

How efficient is your system?

A generator will be rated in kVA which stands for kilo-volt-amperes. This is the measure of apparent power. In a really efficient 100% system the kW will equal kVA. However it’s rare that any system is 100% efficient. If you know the efficiency of the electrical system you can convert kVA to KW. Remember that the closer the power factor is to 1, the more efficiently the kVA is converted into kW - and this is good.

How much power is enough?

On average, international standards say that a power factor of 0.8 is good for generators, therefore if your wattage is around 100kW you’ll need a generator with 125kVA. You need to know whether your generator is going to be a standby for you or your source of primary power. You’ll need at least around 80% capacity if you’ll be using your generator as your main source of power. 

What are the site conditions where you’ll be using your generator?

Once you’ve worked out your load size and the running requirements, you’ll have a pretty good idea of how much electrical input you’ll need from your generator.

The site access will determine how we’ll deliver and offload your generator to you. It can also affect sizing. If it’s narrow, off road or uphill, then this can be difficult to get it on and off site. Limited space means there may not be room to extend what’s known as the ‘stabilizer legs’ to offload the generator as well as operate the crane to position the generator. 

Generator Hire Solutions - for the best in generators.

Make sure you always speak to a trained and certified electrician before you hire from us, and once you know all the specifications, we’ll be more than happy to help you with your choice of generator hire. We have an impressive range of generators for hire in size, power and all with the latest technological innovations. Contact us to find out more.

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