6 Secrets Before Buying An AC Generators

Cost and maintenance are the essential considerations for all kinds of appliances. You might wonder that words like frequency, phases, and voltage are tricky. They might need you to go with a professional with you so that he may check these things.
AC Sychronous Generator

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AC generators have become the need of the hour to overcome unexpected power outages. They come in handy whenever you plan a trip off the grid too. Innumerable varieties of generators are available in the market. The critical thing to keep in mind is that a cheap product doesn’t guarantee durable quality.

So here are the key factors to consider before buying an AC generator. These factors would help you find the best and most suitable generator for your use.

1. Size of the generator

The first thing you need to think about before buying a generator is its size. The size of the generator gives a rough estimate of the capacity of the generator. Total is the load that a generator can power.

Kilowatt, kW, or kilovolt-amperes, KVA defines the load of the generator. Your generator must be able to supply the power to all the burdens of your need. Not only that, it should have a little cushion of almost 20% as a spare. For a rough estimate, if you need a generator of 500kW, buy the one having a capacity of 700kW.

This would help the generator to have a little extra capacity despite working. You should keep in mind that kVA measures apparent power. It is the total power your generator can produce. So kW measures the functional ability. And it is the actual amount of energy that converts into useful electricity.

As an educated estimate (James, 2020),

  • For small homes or businesses: 10kVA or 10kW generator’s capacity is enough.
  • For small to medium-sized companies: 60 kW
  • For large businesses events or smaller industrial applications: 200 kW
  • Very large worksites, industries, or heavy-duty industrial applications: 2500 kVA or 2000kW

To know the exact capacity, you have to calculate the power rating of each appliance. And then add to get a gross sum of the power rating required.

AC Generators

2.Time-frame of generator’s operation

The time frame for the operation of the generator is an essential factor to consider too. Before buying the generator, make sure that you need it for standby purposes or prime duty rating. A standby duty means that you will use the generator when the power from the grid gets disconnected. Instead of waiting for the main power to come on its time, we use the generator for standby purposes.

In short, a standby generator acts as backup power to ensure that the work doesn’t get stopped due to a power outage.

A prime duty generator is one that you use for extended periods. The time may extend from more than 8 usual hours. The excellent duty generator can also be a primary source of power to the household or the business.

Likewise, portable generators come in both standby and prime duty ratings. The excellent duty rating is usually 80% of the standby duty rating.

3. Type of fuel and its efficiency

You should always ensure the type of fuel the generator requires. Because the generator works on power not available nearby your house, it can be an extra burden to you. For generators of considerable size, it is diesel, coal, or natural gas. And for small generators, it is either gasoline or diesel.

This’s not a hard and fast rule, but it all boils down to one thing, i.e., your feasibility. Any equipment bought to provide you with ease should not be a burden to you. That’s why always check if the fuel is available nearby your home. And if it is cheap enough not to become a burden in case of lengthy power outages.

Generator’s fuel options are expanding nowadays due to the ever-increasing technology. So not only diesel and petrol but also biogas and natural gas have become the sorted out fuel. So we discuss the type of energy and efficiency with the manufacturer before buying.

Starter for AC Sychronous Generator

4. Generator’s technology and noise mechanism

Various kinds of generators are available in the market. They range from cheap, mid-range, and expensive ones. But the more fantastic price is never a benchmark for good quality and the latest technology. So before buying a generator, do some window shopping. And get to understand the kind of technology the concerned factory is providing.

Design and efficiency innovations have led the latest technology generators to consume less fuel. They not only use less power but also they run longer and are cheaper.

Noise is another essential factor to consider. Small generators with outdated technology are noisy. While medium and large ones with the latest technology come with noise-proof accessories.

So choosing the best ones will need a bit of market study. Because we would never want you to buy a generator in the hassle and then regret your decision.

5. Generator’s phases and voltage

You can find the generator’s phases by calculating the number of coils in the stator. Generators with the latest technology come with three-phase provision. Because three-phase generators are more consistent in power provision than single-phase generators.

Likewise, you can find the generators’ voltage by the type of appliances it can power. Generators come in three standard types of voltage provision mechanisms. They range from low, medium, and then high ones (PEI, 2017).

  • The low voltage ranges from 50V to 600V.
  • Medium voltage ranges from 600 to 13,800 V
  • High voltage ranges from 13,800 and above.

Poles of an AC generator are also a factor to consider. Poles of a generator refer to the number of magnetic poles present within the alternator. They range from two poles to most of six poles.

The two-pole framework of the generator is usually less efficient. Due to this, it provides less consistent power. The reason is that fewer poles’ generators have to revolve with higher revolutions per minute to fulfill power needs.

In the case of six poles, the revolution per minute is less. This makes them efficient and provides consistent power as a result.

Generators with six poles are usually expensive. So a balanced approach for you would be to consider a generator with four poles.

Testing for AC Generators

6.Frequency of the AC generator

Frequency is the number of times an AC generator current changes its direction. The manufacturer gives it to Hertz. The reason you need to check the frequency of the generator you intend to buy is the power grid. Power grids of different countries provide different frequencies.

In some countries, power grids use a frequency of 50Hz. While other countries prefer the frequency provision of 60Hz. (Parade, 2018). So simple online research would tell the value of the frequency your area’s grid provides.


Cost and maintenance are the essential considerations for all kinds of appliances. You might wonder that words like frequency, phases, and voltage are tricky. They might need you to go with a professional with you so that he may check these things.

But, this is not the case. Suitable quality generators come with a manual. These manuals have all the necessary information about the generator power, voltage, and phases.

Now you don’t need to worry. You can double-check the values written in the manual with the ones you’ve researched. If they match, it’s good to go. A proper background search goes a long way in helping you save money and buy a good quality generator.

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Hey all, I'm Baymax Yan, working at a generator manufacturer and Having more than 15 years of experience in this field, and I belives that “learn and lives.” The sure thing is that I can often help my work. So I have created the blog to share all my knowledge with you. Hope my sharing helps!

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