How to Calculate Three Phase Power in the Data Center (And Why it’s Important)

To illustrate the importance of calculating three phase power in the data center, let’s pretend you are going to cook a meal for a big group of people. As simple as it sounds, first you’ll need to figure out how many guests will be arriving so you don’t run out of food and wind up in a pinch.

In the data center, this planning process is called capacity planning. Only in this case, instead of feeding food to people, you are feeding electricity to servers.

Electricity is expensive, and dangerous; if you exceed your allotted power thresholds, you could wind up paying more and damaging your equipment or starting a fire. So before you approach an electrician about purchasing power breakers and cables, it’s important to have a clear idea of how much power each room will require.

So, how do you actually go about this?”

“To me the easiest way to solve three phase problems is to convert them to a single phase problem,” explains Steven McFayden of myElectricalEngineering. “Take a three phase motor (with three windings, each identical) consuming a given kW.  The kW per winding (single phase) has to be the total divided by 3.  Similarly a transformer (with three windings, each identical) supplying a given kVA will have each winding supplying a third of the total power.  To convert a  three phase problem to a single phase problem take the total kW (or kVA) and divide by three.”

Server Technology makes it easy to calculate three phase power in the data center, with the help of our partner Sunbird's Power IQ software and purpose-built, three-phase power distribution units (PDUs).