In order to understand which type of UPS is best suited to your needs between single-phase UPS and three-phase UPS, it is necessary to examine the loads that must be protected by the UPS.
The information necessary to be able to carry out an assessment are:
- The voltage range of the equipment;
- The kVA of the machines to be protected.
In general, the single-phase UPS is mainly used to protect devices with loads below 20kVA.
This is the first substantial difference between single-phase and three-phase UPS.
Unlike the single-phase UPS, the three-phase UPS is used for loads over 20 kVA.
A further UPS difference may concern the type of equipment to be protected.
In general, IT tools (for example servers) use single-phase current while medical tools (for example machines for magnetic resonance imaging – MRI) can use three-phase power.
If a three-phase UPS is installed, it is possible to choose between 2 configurations:
- Three-phase UPS | Single-phase = Absorbs three-phase current and returns single-phase current;
- Three-phase UPS | Three-phase = It absorbs three-phase current and returns three-phase current to the loads.
Other factors to consider when choosing a three-phase UPS are related to industrial market preferences.
Three-phase UPS are generally used in the petrochemical field Single-phase as the factories want to avoid the hypothesis of problems related to the load balancing required by three-phase UPS | Three-phase.
With a 30 kVA three-phase UPS, 10 kVA of power are available on each of the three phases downstream, with the need to balance the loads sustained to guarantee an almost identical load on each of the three phases without exceeding the capacity of the individual phases.
On the other hand, the use of a three-phase system allows for a centralized power protection plan with a single large UPS used to protect an entire building or series of critical circuits, so this solution can simplify the power protection plan.
What is the difference between single-phase and three-phase UPS?
The fundamental differences between single-phase UPS and three-phase UPS can be highlighted by analyzing the following components and the following features:
• Efficiency | UPS:
o For low power requirements, single phase UPS is more efficient than three phase UPS;
o If the energy demand is higher, the three-phase UPS shows higher efficiency to carry a higher load more safely.
• Cost | UPS:
o The transmission lines for single-phase power supply need large gauge copper wires;
o The equipment in the three-phase UPS system will have longer life expectancy and, therefore, in the long run, the three-phase UPS will save more money.
• Application | UPS:
o Single phase UPS units are available in those applications typically below 20kVA, such as homes, small businesses and satellite offices;
o Three-phase UPS units are commonly used in large installations such as data centers and large industrial power applications.
• Conductor | UPS:
The number of conductors is different in single-phase and three-phase UPSs:
o The single-phase UPS contains one conductor;
o Three-phase UPS supplies power via 3 conductors.
• Sine wave | UPS:
o Single phase UPS provides single sine wave;
o The three-phase UPS provides 3 sine waves, each out of phase and spaced 120 ° from each other.
• Maintenance | UPS:
o In single-phase systems, the plug and play feature of the UPS facilitates installation and configuration;
o In three-phase systems, external installation is required.