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 that are 120 degrees offset from each other. It requires four wires, three for the 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. In three phase electricity transmission, the voltage does not flicker at all. This is the reason for less vibrational effects on the motor.

The three phase converter, also known simply as the phase converter, has three wires that carry the same current, thereby offering a balanced load. It provides a smoother and more efficient service and the equipment that runs on it 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, and it is not provided in many rural areas. In all these cases, one has to use a single phase to three phase converter. It 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 converter. Some of these convert single phase power into unbalanced three phase power. However, quality converters provide true, balanced three phase power, which can be used for gadgets like ovens, computers and motors.

The other most common, three phase converter, is the variable frequency drive, which controls the rotational speed of the ac power by controlling its frequency. 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 converters.

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