Our Brands

My Documents

Welcome to the ASCO Website

Welcome to our website.

A Guide to 3-Phase Power

In this article, we’ll be discussing 3-phase power systems, their benefits, and how they compare to single-phase systems.

Phases in Electrical Circuits

What is a phase in an electrical circuit?

A single-phase system sends current to a load via a single wire, while a 3-phase system uses three conductors, each known as a phase conductor. When talking about phases, we’re talking about wires in an electrical distribution system and the neutral conductor that can be found with them. Typically, 3-phase systems are used to conduct greater amounts of power at higher voltages than single-phase systems.

What Is Single-Phase Power?

Single-phase power is sometimes called “residential voltage.” That’s because it's used in most homes to power electrical devices and equipment.

A single-phase power system supplies alternating current power where the instantaneous voltage rises and falls multiple times each second. The complete rise and fall of an alternating current is considered one cycle, and the number of cycles per second is known as frequency, expressed as cycles per second or Hertz. When discussing power distribution in a single-phase system, it’s important to understand that a phase wire carries the current and the neutral wire provides a path for the current to return. The most common frequencies are 50 and 60 Hertz, depending on regional standards across the globe.

One characteristic with single-phase power is that it’s not able to generate a rotating magnetic field. A motor in this circuit will require additional measures to make it start and run.

These are the benefits of using a single-phase power supply:

• Single-phase power systems provide alternating current over one phase conductor and neutral conductor
• They are small and relatively inexpensive, and thus well-suited for a residence that runs non-industrial devices
• Single-phase power systems are easy to design and operate
• Single-phase power systems have increased efficiency of transmission

What Is 3-Phase Power?

Three-phase power provides three alternating currents on separate conductors. These alternating currents increase and decrease at different times within each alternating current cycle to produce a more constant and consistent voltage than single-phase systems.

Three-phase power systems most commonly use three phase conductors and one neutral wire.

Benefits of Using 3-Phase Power

So what are the benefits of 3-phase power? Why would someone opt for 3-phase power when there are simpler single-phase power systems? Here are just a few of the benefits of 3-phase power.

3-phase power can help run loads more easily

Single-phase power might be great for a home, but for a factory using industrial-sized machinery, single-phase simply isn’t going to work. 3-Phase power is absolutely required for heavier electrical loads, whether it’s a large office building or a factory.

3-phase circuits need less conducting material for transmitting larger amounts of power

3-phase power systems typically carry electricity at higher voltages. When compared to a single-phase system, a 3-phase system can transmit more power through conductors of a given size. This results in lower overall wiring costs than would be incurred to distribute the same amount of power through a single-phase system.

Smoother power supply

The offset timing of sub-cycle voltage changes between the three phases smooths out power delivery, a quality that’s beneficial to load equipment such as large motors.

For new entrants to the power business, understanding the difference between single-phase and 3 phase power is essential. For more information about elementary electrical concepts, see other articles on the ASCO Power Technologies website.

If you’re looking to improve power reliability, ASCO Power Technologies can help. We consult with companies worldwide to help them optimize power availability. Contact an ASCO representative today.