Why Do Today’s Server Applications Use 54-V BLDC Motors? (.PDF Download)
Nearly everyone has heard the term “cloud-based computing,” yet most of us who rely on being able to access important data from our computers and smartphones don’t think much about where the data is actually stored. So what is cloud-based computing? Cloud-based computing refers to a mesh of remote servers that stores and moves data around the world so that we can access via Wi-Fi, local-area network (LAN), or a cellular network.
These remote servers act as a large storage device that consists of clusters of servers in a warehouse commonly referred to as a server farm. These server farms require a constant ambient temperature (optimal temperature range is between 68° and 71°F) to operate at their highest performance and to minimize any failure. They’re typically cooled by central air conditioning or heated with central heating depending on their location, just like a typical office space.
The actual server racks use a series of fans that cool the electronic components inside them. As most of us have experienced, electronic equipment heats up as it’s utilized, which eventually will affect the maximum performance of the equipment. To minimize the cost and size of heat sinks, the electronics are cooled by air flow using brushless dc (BLDC) fans to take advantage of the ambient temperature, which is kept constant by heating, ventilation, and air conditioning (HVAC) to cool the electronic components in the server rack.
Traditionally, server applications have used 12-V BLDC fans to cool the electronics in a cabinet. However, just like automotive applications, 54-V BLDC motors are being adapted for server applications for several reasons. This article discusses the two main reasons why server manufacturers are adopting 54V BLDC motors rather than traditional 12-V BLDC motors. It also breaks down the typical components required for 54-V motor-drive applications as well as some of the common motor-control algorithms.
Two Reasons for Switching to 54-V BLDCs
Server manufacturers are adopting 54-V BLDC motors over traditional 12-V BLDC motors because it allows them to use one fourth of the current. In turn, motor manufacturers can use thinner copper wire. This also enables motor manufacturers to reduce the size of the motor and, therefore, the overall cost of the motor, because fewer raw materials are required to perform the same work load. Secondly, server manufacturers save on the cost of expensive cables—one cable can power four times the number of motors using a 54-V BLDC motor compared to a 12-V BLDC using the same power bus gauge cable. For the same power, higher-voltage motors can use smaller cables or a narrower PCB track width.