What Is A 3 Phase Generator (And Difference Between Single-Phase Generator)

Buying a new generator can be a daunting experience, especially if you don’t have a lot of knowledge of the subject. 

One of the phrases that can trip people up when researching generators is ‘3 phase’. You might also see generators referred to as ‘single-phase’.

What Is a 3 Phase Generator (And Difference Between Single-Phase Generator)

This kind of terminology can be confusing if you don’t know what it’s referring to and what the distinction actually means in terms of functionality and application. 

So, what do these terms mean, and what’s the difference between a 3 phase and a single-phase generator? 

We’ll be answering both of these questions in today’s article before giving you some guidance on choosing the type of generator that will meet your needs most effectively. 

What Is A 3 Phase Generator?

A 3 phase generator is a generator that uses AC (Alternating Current) power. AC is the term for a current that changes direction by reversing at intervals instead of flowing in one direction continuously.

This directional change increases the maximum power level of the generator, which tells us that 3 phase generators are capable of high power output. 

What really defines a 3 phase generator, however, is the fact that this type of generator has 3 sequenced AC currents running at once. As you can imagine, running 3 currents at the same time requires a pretty substantial power input, but the benefit is that the power output is constant and strong. 

The current sequence for a 3 phase generator is set to 120-degree offset patterns. This means that the different currents reach their peaks at different times so that when one gets low, the other increases.

This is how a 3 phase generator maintains consistent power, because every time one current drops, another essentially takes over. The result is better overall energy efficiency. 

3 phase generators are versatile pieces of equipment because they can be wired to either a single, industrial appliance or to 3 smaller appliances. 

What Is The Difference Between A 3 Phase And Single-Phase Generator?

Before we get into the differences between 3 phase and single-phase generators, it’s worth touching on some of the similarities between them. 

For one thing, both single-phase and 3 phase generators use AC power for increased power output.

Additionally, because they use AC power, both generator types rely on power cycles (where the current peaks and then drops in sequence). 

The key difference between 3 phase and single-phase generators is that where 3 phase generators run 3 AC currents at the same time, single-phase generators operate on only one current. 

This means that while 3 phase generators need an increased voltage to run, the power input required to operate a single-phase generator is lower. This might sound great on the surface because it implies that less electrical energy is used overall. 

However, it’s not that straightforward. Because there are no additional currents to balance the power, when the single-phase generator’s current gets lower, the power output drops significantly.

Usually, this won’t cause the generator to drop out altogether, but it does mean that power output from a single-phase generator is less consistent. So, even though you don’t need as many volts to power the generator itself, you’ll be losing out on energy efficiency due to the fluctuations in power output. 

Additionally, whereas 3 phase generators are powerful enough (due to their high running voltage requirements and output consistency) to power industrial appliances, single-phase generators are suited to much lighter electrical loads, such as individual lighting fixtures. 

Another thing that’s worth noting about single-phase generators compared to 3 phase generators is that the former, despite costing less upfront, will typically rack up more maintenance expenses.

That’s because the fewer power fluctuations in 3 phase generators result in less torque than single-phase generators. Torque creates mechanical vibrations, which can cause internal wear and tear over time. 

What Type Of Generator Should I Get?

Whether you should buy a 3 phase or single-phase generator ultimately depends on what you’re planning to use your new generator for. 

Generally speaking, single-phase generators can handle electrical loads up to (but not exceeding) 240 kilowatts. If the electrical load goes above this, you run the risk of your power source dropping out altogether. 

If you’re intending to use your generator to power a single laptop, desktop computer, lighting fixture, television, or similar, then a single-phase generator could be the right choice for you. 

However, if you have more substantial power demands to cater to, you’ll probably need a 3 phase generator. 

If, for example, you’re looking for a generator that can power your whole apartment or house during an outage, you’ll need a backup power source that can be wired to multiple appliances at once and sustain a significant electrical load. 

This also extends to industrial or commercial power requirements, such as agricultural equipment, air conditioning, or commercial refrigeration. These appliances need a lot of power to run efficiently, so a single-phase generator simply wouldn’t work in this situation. 

Final Thoughts 

Ultimately, the main difference between a single-phase generator and a 3 phase generator is the number of currents that each generator type uses. 

While a single-phase generator operates on a single up-and-down current, 3-phase generators have 3 AC currents running simultaneously, but on different cycles.

In 3-phase generators, the currents’ peaks and troughs are sequenced to happen at different times so that there is a consistent output of power. 

Therefore, a 3 phase generator is both more powerful and more efficient than a single-phase generator.

It’s also more durable because there is less torque, which means fewer damaging mechanical vibrations. On the flip side, this type of generator is more expensive and requires a higher voltage input to run properly. 

3-phase generators are best suited to powering either one large, industrial-scale appliance or several small appliances at once. However, single-phase generators typically can’t sustain electrical loads above 240 kilowatts, so they’re only really reliable for single, small devices such as computers and televisions. 

I'm an environment and energy blogger who teaches outdoor and energy enthusiasts how to be better informed when it comes to purchasing or maintaining a generator, solar panel system, or anything else related to your energy needs.