What is the difference between single phase and three phase power? What is the advantage of three phase over a single phase pump?
Morgan Byres | Feb 9, 2023
Buildings are typically wired with either three phase or single phase power. Three phase and single phase refer to the number of waves (phases) of current being delivered, this can usually be determined by the amount of hot leads.
What is single phase power?
Many homes and small businesses have single phase power. Single phase power has only one hot lead. The electrical current cycles in waves, and when you only have one source of power it creates a small gap in the power output. This does not matter when running smaller items, such as a hairdryer, however, it does affect motors above 5 HP or those drawing a significant amount of power.
What is three phase power?
Most industrial environments are wired with three phase power, this allows you to run larger motors. In this configuration there are three hot leads. The three waves of current are stacked in order to deliver a constant flow of electricity (there are no breaks in current). Each wave peaks sequentially and therefore there is never a break in current. As a result the power is more even and has no disruptions. It is also more efficient and less expensive to use three phase power, as it draws less current than single phase.
What power should you use for a pump?
This is a bit of a trick question. Our pump motors require three phase power; an uninterrupted source of electrical current. However, if you have single phase power there is another option: a VFD. VFDs can convert single phase to three phase, however there are limitations. This conversion works really well up to about 3 HP, then the feed wires required have to become larger and the process becomes more difficult. 115v single phase is only available in our portable assemblies for 1 1/2 HP and lower, while 230V single phase is available for up to 3 HP (5 HP by special order). Single phase power can be converted to three phase power for even larger motors when there are no other options, however, it is not recommended.
Finally, three phase power is always going to be better for your pump; it creates a continuous flow of power to your pump motor and does not require converting, but the convenience of single phase on the smaller motors sometimes makes it the better choice.