Saturday, February 5, 2011

Single Phase to Three Phase Converter

Phase converters are used to convert the single phase power to three phase power. Three phase power is a popular way of transmitting electricity. The power plant that generates power, produces three different phases of electricity simultaneously. What is three phase power? Have you ever wondered why three? And why not two or four? The answer to this question is simple! These three phases are 120 degrees offset from each other. The three phase power requires four wires, three for the three phases and one for neutral. There are three phases because in a 360 degree cycle, there are three instances when the power waveform has a peak value. These values are shifted by an angle of 120 degrees. Usually, the utility companies provide earth as a ground connection.

There are many advantages of three phase power. The three phase converter, also known simply as the phase converter, has three wires that carry the same current, thereby offering a balanced load. In three phase electricity transmission, the voltage does not flicker at all. This is the reason for less vibrational effects on the motor. Three phase converters, thus, provide a smoother and efficient service and the equipment that runs on the three phase power last longer than those that run on single phase power. Usually, utility companies provide single phase as well as three phase power. However, the prices of three phase power service is comparatively very high. In many rural areas, three phase power is not provided. In all these cases, one has to use a single phase to three phase converter. The single phase to three phase converter is also called true three phase converter. The single phase to three phase converter is a much cheaper option than asking the utility companies to install a three phase power system at a required site.

The rotary phase converter is the most common single phase to three phase converter. Some rotary converters convert single phase power into unbalanced three phase power. However, quality three phase converters provide true, balanced three phase power. High quality, heavy-duty, rotary three phase converters provide reliable and efficient three phase power. This three phase power can be used for gadgets that run on three phase power, like three phase ovens, three phase computers and three phase motors.

The other most common, three phase converter, is the variable frequency drive. The variable frequency drives control the rotational speed of the ac power by controlling its frequency. The voltage of the three phase converters can be varied according to the voltage. They are commonly used in variable frequency motors, generally used in fans to save electricity. The frequency drives are commonly used in the conveyors and pumps. The three types of frequency drives are constant voltage, cycloconverters and constant current, from which the constant voltage drives are most commonly used.

In power systems, a digital phase converter uses a rectifier and inverter. A microprocessor based system is used to control the switching process and monitors the phase conversion. The output of the digital phase converter is pure sine wave and gives a balanced voltage as compared to other three phase converter.

The oldest three phase converter is the static three phase converter. They use two capacitors and a relay switch to convert the power from single phase to three phase. However, researches have proved that static three phase converters have a poor performance and also overheat the equipment that they drive. All these drawbacks are responsible for discarding the static three phase converter.

Three phase motors are preferred over single phase motors. There is a switch in single phase motors that connects and disconnects the secondary winding to the capacitor. Frequent switching of the secondary transformer causes overheating and the switch contacts get corroded. The three phase motor on the other hand, does not have a switch to connect and disconnect the secondary winding, which leads to a long motor life. Hence, the three phase power is preferred over the single phase power. The three phase converter is an important requirement of many industries and farms, which require heavy voltages.


  1. Please I would like additional information on how to build a digital phase converter using rectifiers and ind inverters as well as micro controllers.

  2. Thank you for posting you blog, are you rearching for online phase converters.

  3. Very excellent explanation which can be understand by every one.Thanks For the Information, It is very useful for us specially schematic diagrams helped a lot.
    VFD Static Phase Converters