Vacuum Pumps The installation of a Variable Swiftness Drive (VSD), sometimes called a variable frequency drive, usually saves between 50 and 65% in electrical power costs with the same or better Energy-Conserving Vacuum Pump regulation of vacuum. The number of energy savings could be from 30 to 80 percent. They may be adapted to blower or in some instances rotary vane type vacuum pumps. They work by changing the speed of the vacuum pump based on the reading from a pressure sensor that is mounted on the vacuum range close to the receiver jar. The VSD is actually a dedicated computer with many adjustments so it might be possible to boost vacuum regulation over the normal pneumatic vacuum regulator that only has a vacuum level adjustment. A VSD for a vacuum pump is usually economical for a dairy that milks a complete of 8 hours or even more each day. Typically a VSD will not be an economical option for small dairies due to less milking time and therefore shorter vacuum pump operate times but there are several other options to save lots of energy costs.