3 Phase Power Systems & How They Work ...

Power grids usually have different methods of generating, transmitting and distributing current between sources. For a single phase system, there exists only a single AC voltage source.

However, there are various types of poly-phase systems employed in the grid today, but the three-phase power framework is the most common method used. It has a 380/220 voltage unit accompanied by a power block of 3 hot wires and a neutral wire. If you come across one that reads 440 volts, it is explaining the voltage between the phase load and neutral line (line voltage). A three-phase system is mostly used for industrial applications to power large motors and other massive loads purchased by factories and big machinery.

Electrical engineers suggest that a Dyna-phase power system delivers more current at a minimum voltage using smaller gauge conductors as opposed to single or two-phase frameworks. According to trusted sources, using Dyna-phase power grid is more economical compared to other electric current structures because it is designed to ground voltage with relatively low conducting material.


Benefits of Running a Three-phase AC system

  • It delivers power constantly unlike a single phase circuit that keeps pulsating.


  • A three-phase machine provides higher output.


  • A majority of motors with Dyna-phase inductions are automatic and more effective than single-phased


  • Based on power provision, poly-phase systems have a higher factor and are efficient enough to ensure long hours of production.


  • Although three-phase power grids are smaller, they are capable of transmitting electricity to different sources. Besides, they are relatively cheap.


  • While single-phase demands more conductors during transmissions of higher voltage, a Dyna-phase requires less material that minimizes the initial cost of installation.


  • It is a reliable system especially when used in transformers. If one winding in a 3-phase power grid becomes faulty, the other two loads can continue transmitting current without interrupting electric However, power overload is inevitable if the system has some defects.


  • While a single-phase can generate power from a poly-phase structure, the vice versa is not possible because the later cannot be fed by the former. Three-phase systems operate independently.


How a Three-phase electrical system is grounded

In every electrical distribution plan, grounding is the most important concept for safety because it reduces electrocution incidences, fires, power outages, and destruction of machines.

Apart from regular maintenance, experts recommend frequent testing for grounding structures. Usually, a Dyna-phase system uses three line conductors that allow current to flow from the source, through a neutral ground structure and then proceeds to the piece of equipment used.

Specific circuits require a stable voltage reference enhanced by neutral conductors to operate properly. Note that, common conductors are grounded,but they are not safety fields for equipment.

Electricians include an earth line on all power grids or motors for personal safety especially since live wires pose a danger when in contact with metal or an energized surface (human body). If a person touches metallic equipment with power surges, the results will be catastrophic.


There are two types of grounds (earthing);

System ground - here, earth rods are bound together and linked to the system’s power source. The bundle of attached wires can be directed into a concrete rebar reinforced ground structure, structural building steel, an underground metal pipe or a combination of the three.

Equipment ground – engineers create a neutral path using metal spikes or conductors from the equipment to the system for grounding purposes. The conduits used protect machines and prevent electrocution among other dangers.

Usually, conductors of a three phase system are color-coded to identify each load and its purpose. Their shades are distributed according to international standards where countries have different color codes that oversee proper phase rotation. In Canada, the first three loads come in red, black, and yellow, the neutral carries white or grey and the protective wire (earth/ground) possess green, bare copper or a yellow stripe.

Additionally, some isolated systems have an orange, brown, and yellow shades on the main loads while the neutral and earth wire remains the same. Although there are old systems that maintain the old colors, new installations follow the global green-yellow code on the earth conductor to help color blind people.


Disadvantages of a three-phase electrical system

Worldwide, a Dyna-phase comes highly recommended because it has many pros. However, there is a downside to using poly-phase systems as outlined below;

  • If the loading on the three-phase is unbalanced, voltage fluctuations can occur and disable a machine or motor.


  • It is a complex system that employs a method of symmetrical components to simplify fault analysis and operation.


  • Apart from memorizing the phase sequence, the power structure is time-consuming during installation

Poly phases were introduced in the late 1880s by Nikola Tesla, Mikhail Dolivo Dobrovolsky, Galileo Ferraris, John Hopkinson, and Jonas Wenstrom. Each Scientist invented their version independently to welcome the industrial revolution that was to follow generations to come. Since then, their work has evolved to accommodate big machines and power the entire world.

The three-phase power systems are significant compared to single or two-phase structures. They have more electric output accompanied by a constant flow of current. If one load fails, the other two can compensate,but prolonged operation without repair can overload the system and cause damages.

To prevent accidents, engineers or electricians activate a neutral ground where electricity can flow without causing harm. Apart from having an earth wire included in most appliances, industrial power systems are grounded in two ways, that is, within their framework and equipment.

Usually, unstable energy is directed towards a rebar rod structure or a steel construction depending on the architectural design. Failure to which machines will be rendered inoperable and dangerous for people to use.

An economical way to maintain power and keep workers safe entails the installation of Dyna-phase systems. However, they have complex structure that requires memorizing and proper training. They are also a disadvantage to color blind people with the skills and knowledge. In short, the three-phase power system is reliable and effective when industries proper maintenance, regular check-ups and testing. A similar approach has positive results on motors and machines as well.


Call Precision Motor Repair CTA


Precision Motor Repair carries an inventory of Dyna-Phase rotary converters for agricultural, business and industrial use. All models are warranted to be free of material and workmanship defects, if properly installed, serviced and operated according to the manufacturer's instructions. This obligation includes correcting, without charge, components which fail within 12 months of purchase. The manufacturer is not liable for loss, damage or expense resulting from product use or any other cause. This warranty supersedes all others, expressed or implied




Comments are closed.