Buying a Single-Phase Vs. Three-Phase Generator

Single-phase and 3-phase generators may be cousins in the power-producing family tree, but businesses and building managers shouldn’t make the mistake of confusing the two for their facility’s energy needs. While both can function to generate primary power for commercial and industrial equipment for off-grid applications or alternative energy in the event of outages, people continually wonder about the differences between single-phase and 3-phase generators, what each can power and for how long.

These are natural questions. As a business or property owner, a facility manager or simply an individual looking to keep their operations and departments running around the clock without the worry of expensive downtimes or production interruptions, understanding the 3-phase motor difference is key. What’s more, if you pick the wrong type, you’re bound to experience more pain points than you had before — from weak and spotty power to sky-rocketing energy bills to an entire malfunctioning fleet of generators.

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Buying a Single-Phase vs. 3-Phase Generator With Woodstock Power

Buying a Single-Phase vs. 3-Phase Generator With Woodstock Power

The best new and used generator purchases are informed ones. What is a single-phase generator, and what is a 3-phase generator? Woodstock Power walks you through their parallels, differences and applications, so you can make the proper selection for your operations.

Before we get into the technicalities, here’s what you need to know about the similarities that form the base of both these generator types:

  • Both Use Alternating Current (AC): AC is a type of electric current that actually reverses direction rather than flowing along continuously in one-way lines. This means AC electricity is slightly more variable than other electrical currents, but it does produce higher levels of power.
  • Both Contain Power Cycles: AC flows work in cycles, with peak and lowered outputs based on how electrons are moving in their alternating paths. Single-phase generators produce and rely upon one AC flow with one up-and-down cycle, while 3-phase produce and cycle three simultaneously.


The Difference Between Single-Phase and 3-Phase Generators

While single-phase and 3-phase generators are built on the same AC flow concept, one fundamental difference sets the two apart and ultimately gives each its name. Each uses a different number of conductor wires to provide power output. The conductor wires allow each generator to produce a different amount of power output.

These generators’ power cycles are the biggest difference between the two. As we mentioned above, single-phase generators produce one AC flow that fluctuates from 170 degrees to -170 degrees. The continuous oscillating wave reaches its peak output, which is when the most power is generated, and returns to a low output. With a single current, it’s more difficult to produce large amounts of power because the wave is constantly dipping back down. However, the opposite is true of 3-phase generators.

The same concept applies to 3-phase generators, though they produce power through three different conductive wires and a neutral grounding wire. These wires, or phases, are all offset by 120 degrees and are synchronized so they never touch or cross paths. Offsetting the phases ensures one of the three waves is reaching its peak at any given moment. This arrangement provides a more even and continuous power output because you don’t have to wait for the conductors to reach their peak.

3-phase generators are essentially three single-phases housed in one unit, enabling them to produce far more power output. When looking at both types of generators, each of the same size, the 3-phase generator has 180% more capacity than the single-phase model. That difference is significant, especially when you need all the power you can get.

3-phase generators are significantly more powerful than their single-phase counterparts. The continuous 3-phase cycle uses those three conductors to give the generator a higher power factor, making 3-phase models ideal for large applications like powering industrial machinery. Meanwhile, single-phase generators are only ideal for smaller applications like powering household electrical circuits.

How a Single-Phase Generator Provides Power

As its name suggests, a single-phase generator uses a single AC wave described above to create its kilowatt outputs. This is the essential difference to this generator type. Since they only work from one “line” of power produced between a small number of conductive wires — sometimes as minimal as two — and that line has up-and-down output cycles, single-phase generators will not provide as steady a power source when compared to its 3-phase counterpart.

Luckily, even at its lowest point, single-phase generators don’t wholly “drop out.” Low cycle currents should typically remain unnoticeable unless running this generator type at overcapacity. This is why you don’t notice lights flickering in a room while a lamp or overhead fixture is on. Commercial lights are a staple application for single-phase generators, yet they cycle so fast, flickering caused by current low points is imperceptible to the human eye.

In total, a single-phase generator is one made up of the following characteristics:

  • Contains one voltage-produced current
  • At the minimum will have as low as only two winding components charging the entire system
  • Uses less conductive winding in general
  • Lower up-front purchasing costs but higher maintenance costs
  • Loads must remain relatively light, such as individual lights, electronics or appliances
  • Single cycles make it less efficient, less powerful and more prone to voltage disruption

How a 3-Phase Generator Provides Power

A 3-phase generator produces power through three sequenced currents running simultaneously. Those currents require a stronger underlying voltage, but with this setup, you’ll have continuous power generated from your unit.

What’s more, that power is not only more constant, but it’s stronger, as well. A 3-phase generator patterns its three conductor wires and one neutral wire to cycle at 120-degree offsets and to be able to maintain power for more intense applications or mission-critical machinery. The 120-degree proration means that as one current’s cycle is at its lowest, another will be at its highest, offering complementary wavelengths that work in tangent to deliver stable amounts of power.

3-phase generators strike a Goldilocks balance between power provided and cost to build and maintain. They have the added bonus of being more versatile, too. Operators can opt to sync all three current cycles to power one large piece of industrial-grade equipment. Or, each conductor wire can connect three smaller pieces of equipment to individual current lines held within the same 3-phase generator.

The former is often the case in factories and industrial applications to power a single machine or system, while the latter works in things like multi-story office buildings to power elevators and the office’s suite of desktops.

In total, a 3-phase generator will be comprised of the following features:

  • Three simultaneous voltage-produced currents fluctuating at 120-degree intervals
  • Requires at least three copper winding components to charge the entire system
  • Uses more intricate winding or wiring in general, though lighter and more efficiently
  • Loads being driven can be heavy and industrial as well as distributed to numerous lighter applications
  • Is the more economical, robust and reliable generator type

The three conductors give these generators a higher power factor. 3-phase generators provide more voltage output, allowing them to power larger and more complex systems. Some businesses, applications and facilities may require higher voltages to power their systems effectively. This is where the three conducting wires are most valuable and are often necessary for operation.

The Advantages of a 3-Phase Generator

The Advantages of a 3-Phase Generator

Understanding the functional and mechanical benefits of a 3-phase generator plays a significant role in picking one that works best for you.

However, while single-phase and 3-phase power are often pitted against each other, it bears noting that the defining element in your purchasing decision is what you will use this generator for. It’s an intuitive question, and it will help you see the actual benefits of the generator for yourself rather than relying solely on confusing spec sheets or flashy salespeople.

For industrial, commercial and agricultural applications, 3-phase generators are your surest bet. The advantages of 3-phase generators to these industries are extensive, including:

1. Stronger, Durable and More Reliable

It bears repeating that the most significant advantage of 3-phase generators is their high levels of power output and even higher levels of efficiency. They are the workhorses of industrial equipment, heavy machinery, large office buildings and facilities alike, delivering steady streams of electricity that are staples in high-demand operations.

2. Lower Overall Lifetime Costs

While they may be more expensive to acquire upfront, 3-phase generators are the calculated winners when it comes to maintenance, system updates and general upkeep. They are more stable and resilient due to less wear-and-tear from torque, heavy loads, pulsating distribution and more. What’s more, when you factor in cases of system downtime or production halts due to single-phase degeneration and patches, 3-phase generators become even more cost-competitive.

Additionally, running several single-phase generators can be costly when trying to power large applications. For the same voltage and power, the transmission cost for a 3-phase generator is less than a single-phase one.

3. Less Aluminum or Copper Per Generated-Kilowatt or Output

This initially sounds confusing, since there are more wires involved in a three-cycle generator compared to a single cycle’s traditional one or two. However, 3-phase generators actually have what’s called a lower power transmission, meaning they need less conductive materials to produce the same amount of power at the same level of volts.

In this case, that means 3-phase generators have lighter copper or aluminum wiring components than single-phase generators, making the whole unit potentially lighter but still more efficient.

4. Less Torque

Less torque in your generator means fewer mechanical vibrations. This, in turn, helps complement the superior reliability of the 3-phase generator over its one-phase counterpart.

Extensive levels of torque will cause a domino-like spiral of effects on your unit. Your AC waves become disrupted and less stable, as magnets shift out of place or other weights and forces damage mechanics, which then means irregular cycles. With harmonious cycles as the backbone to AC generator types, you’ll end up with a less sturdy and less functional 3-phased unit.

5. Superior Power Factor

Most 3-phase generators average a .8 power-factor rating. That’s nearly 1.5 times higher than the typical power factor of a single-phase generator of the same size and weight. These higher power-factor numbers mean larger final outputs capable of handling your industrial applications.

When Should You Choose A Single-Phase vs. 3-Phase Generator?

The most significant factor in choosing a single-phase or a 3-phase generator is what you intend to use it for. More specifically, consider what kinds of equipment or devices need to be powered, how often and for how long.

When You Should Choose a Single-Phase Generator

Business owners and facility managers should consider opting for single-phase generators when applications require power less than 240 kilowatts. Generally, single-phase generators are not meant for scale. They are also not ideal for powering advanced or around-the-clock equipment unless that equipment comes highly specialized or is somehow buffered by another power source.

Building managers or operators aren’t recommended to utilize single-phase generators for the majority of their facility’s major systems. Those systems include things like heating, cooling, air ventilation, elevators, large electronic systems and industrial or production equipment. Each of these will likely be unable to function without a proper high-output source, like what’s provided with 3-phase power.

Because single-phase units are best in residential uses, they are only recommended for low-power appliances and equipment, such as:

  • Individual or small sets of desktop or laptop computers
  • Individual lighting systems
  • Televisions
  • Modems
  • Backup portable generators

When You Should Choose a 3-Phase Generator

3-phase generators are the clear choice for commercial and industrial usage. They can withstand longer run times, sustain higher voltages and perform with a maximum degree of stability and reliability.

It is especially imperative for business owners and facility managers to outfit their buildings with 3-phase generators in the event of a power outage or emergency. In some industries, a power outage can cost thousands in profit-cutting expenses per minute — not to mention, in some cases put lives at risk. Without a backup power source, your facility risks lost revenue and many other business-critical liabilities.

You should choose a 3-phase generator if your plant or operation relies upon any of the following:

  • Industrial Equipment: Large motors and other heavy-load engines, commercial refrigerators, conveyor systems and industrial fabrication machinery — manual and computerized
  • HVAC Systems: Central air conditioning, commercial or industrial-grade electric boilers, furnaces or baseboards, space heaters and air ventilation — including exhaust, supply or balanced systems
  • Heavy-Duty Agricultural Equipment: Tractor-driven power take-off generators, large engine-driven alternators and open standby units

Industries and Situations That Usually Require a 3-Phase Generator

Industries and Situations That Usually Require a 3-Phase Generator

3-phase generators are essential for many business types and situations. Without proper 3-phase generators to backup operations, augment specific pieces of equipment or produce power in the field, it is impossible for the following industries to function at peak productivity.

1. Small Batch and Continuous Manufacturing

Numerous studies have found manufacturers have the most to lose from a power outage or disruption. Whether small-batch production lines or an around-the-clock fabrication facility, manufacturing knows how vital a reliable, industrial-grade source of power is. Facility managers work to ensure their power grids are secure and sustained, as well as buffer them with their own backup 3-phase generators to keep machines operational and computer systems regulated. Without these, a facility will be rendered lifeless.

2. Food and Beverage Processors

Perishable food and beverages rely upon continuous power to keep cold-refrigeration and other preservation storage methods working. With inventory extremely liable to contamination and shortened or tainted lifespans, a single power outage can force you to throw out thousands of products.

Food and beverage processing managers should have a complete suite of 3-phase backup generators on-premise to assist in these times of need — at the very least to keep temperatures regulated and air ventilation cycles sterile.

3. Multi-Story Office Buildings, Towers and Skyscrapers

The large and complex electrical systems outfitted in multi-story buildings require an equally dynamic system. 3-phase generators are the natural choice for electrical engineers and building managers alike to regulate power on each floor. What’s more, these power levels must be consistent regardless of the story or its electricity demands. Only 3-phase generators carry the versatility to distribute currents to multiple applications, as well as with the steadiness and uniformity high-rises need.

4. Agricultural Equipment, Attachments and Power Tools

Few sources of power can meet the requirements of agricultural work. Electricity is necessary for farms to function in nearly every branch, from temperature and ventilation regulation in livestock buildings to powering irrigation systems or planting and harvesting machinery. With these operations happening on the daily, static and portable 3-phase generator units are the go-to powering choice to complement current systems or boost the functionality of field equipment attachments and tools.

5. Data Centers

As cloud-based and outsourced data storage continue to rise, so, too, does the importance of powering those centers. These massive facilities cannot risk a power outage — even for a few minutes — as outages spell the potential for irreversible records loss or damage on top of subsequent liability complications. Those in the finance, telecommunications, healthcare or IT sectors need reliable data centers fueled by 3-phase power sources to keep data transactions smooth, secure and glitch-free.

New Or Used Three-Phase Generators to Power Your Commercial or Industrial Operations

New Or Used 3-Phase Generators to Power Your Commercial or Industrial Operations

You have questions, and we have answers. Choosing the right phase generator for your property is not something you decide on a whim. Woodstock Power can help you consider your business’s, plant’s, farm’s or facility’s exact grid and power layout and operational needs to find the right generators to tie it all together.

We’re always here to answer your inquiries and protect your business from expensive downtime. Reach out today through our online contact form or at (610) 658-3242. We can’t wait to work with you.

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