Sensata Technologies. The White Paper looks in particular at how ‘old technology’ water pumps that tend to operate at full speed or not at all are being replaced by Variable Speed Pumps (VSP) that use a Variable Frequency Drive (VFD) or Variable Speed Drive (VSD) to continuously optimise the pump speed and power consumption while maintaining constant outlet pressure of the pump. In such scenarios, pressure sensors are essential. A pressure sensor converts the outlet pressure to an electrical signal which the VFD uses to adjust the pump’s speed and is either included as an integral part of the pump design or mounted externally as part of a total solution. Similarly, in many cases, a high cut-out pressure switch is mounted to prevent the pump from outputting extreme pressure. An additional pressure sensor can also be mounted on the inlet of the pump to monitor efficiency. The benefits of pressure sensors in modern-day Variable Speed Pump design can be categorised into three key areas: efficiency; reliability; and the user experience.