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Generators - Frequently asked questions

Date posted: 19 March 2015

You can easily handle all your power generation needs by getting a generator that meets your specific requirements, to avoid undue stress on the unit and get the job done efficiently. One of the many aspects you need to consider is the size of the generator, and it involves numerous factors. To prevent the confusion deriving from deciding whether to use a 3-phase, single-phase, KVA, standby, KW, or motor starting generator, we have developed this article that should give you a pretty clear idea as per the sizing-related matters, and not only.

Q: Why is it so important to choose the right generator?

A: To name a few, choosing the right generator will help you prevent unexpected system failures and shutdowns (due to overload), increase the longevity of the asset, to have a smoother, worry-free maintenance, and avoid asset damage.

Q: What kind of generators are available on the market right now?

A: Electric engineering has evolved in the last decade, offering generators a broad range of power supply capabilities, ranging from 5KW and up to 50KW (for personal/residential use), and to over 3MW for industrial use, depending on your power requirements. 

Q: Is it true that using smaller generators for Standby Electric Power is recommended?

A: Absolutely not. Don’t be drawn into that myth. In fact, a generator that is under sizing involves several risks. You may damage the generator AND the assets connected to your generator, limiting the unit’s overall productivity and creating dangerous situations.

Q: How much power do I need?

A: Besides having a certified electrician determining the right size of the generator for you, you can also get started with the following guidelines to head towards the right direction:

  • Delve deep into your requirements for power generation before purchasing a generator. Make a list of what item needs to be powered and note down the starting and running wattage for these items (you’ll find them in the owner’s manual or the identification plate). Your power requirements should be calculated in KW or KVA.
  • If your power requirements are in amperes, convert them to Watt. There are many conversion calculators, such as Rapid Tables, to help you.

Q: Do I need to get a long-run fuel tank generator to get maximum power effect?

A: If you want to purchase a generator just to keep your mind safe in case of a power cut, a long run tank fuel asset is recommended. Now, if you don’t require a backup power supply unit that will get you through the entire night, you can get a generator with a standard run version that will last for up to 4 hours.

Q: Do I run a home computer from a standard generator?

A: No, you are not advised to do that. What you need is a generator that utilises Automatic Voltage Regulation (AVR), such as the Honda EU& EM Range inverter or the Briggs Pro Max 6000A to get more stable electricity. 

Note: To avoid surging (when the generator runs out of fuel), you can use a UPS (Uninterruptible Power Supply) which is an equipment that helps computer users save data in the event of a power cut.

Q: Is using a personal power breaker a good idea?

A: The generator and the mains supply have different configurations. The first has a floating earth and the latter has an earthed neutral configuration. Using an RCD (personal power breaker) is recommended for the mains. In fact, it is meant to run from the mains. However, for most cases, using one with a generator is unnecessary, given that the generators are assets designed to be safe.

In case you want to use a power breaker with a generator, you will have to modify the generator so it has the same configurations as the mains. This can be done quite easily by a qualified electrician, but you will then need to use a personal power breaker EVERY TIME you use the generator and always have an earth spike connecting the ground and the frame of the generator. Due to its uncertain results (can you ensure you get that right every single time?), it is not recommended to modify the generator.

Q: How do I connect the generator to my house, in case mains fail?

A: You must take some precautions when intending to have a generator as an alternative mains supply. First of all, the generator should be isolated from the mains supply, so it doesn’t attempt to power up the entire block. This will also protect a utility worker that will attempt to restore the mains supply from being electrocuted. To accomplish that a certified electrician must install a changeover switch (break-before-make, double-pole), which should be fitted between the building consumer unit and the electricity meter. This switch will connect the building to a lead plugged into the generator or the mains supply.

Note that the majority of buildings have a built-in RCD into their consumer unit that is configured to run with an earthed neutral from the mains supply and NOT a generator. Modifying the generator in a way that is the same as with the mains supply (always by a qualified electrician) will allow you to utilise this protection device and will also ensure that the generator is safe (unmodified) when disconnected from the house.
Important Note: Always use a steel armored cable for the generator-transfer switch connection, as the lead between those two is NOT protected by the RCD. Plus, you also need to install a local earth spike (low-impedance).

Q: If I want to start a motor, what size generator do I need?

A: Truth is there are several designs of motors, and each one has various characteristics. For example, some motors require a larger generator because the need additional current to start (e.g. induction motors). The motors that don’t usually need additional start-up current are those fitted to hand tools. Therefore, it is best to ask the asset’s supplier as to whether it requires additional current to start.

Q How do I hire a generator?

If you are looking to hire a generator you can visit Best at hire your National tool hire supplier. We have a wide range of generators for hire, suitable for all applications. You can simply call us today for free expert advice and we can deliver directly to your door. Most of our equipment is available for next day delivery.

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