Energy-Conserving Vacuum Pump vacuum Pumps The installation of a Variable Rate Drive (VSD), sometimes called a variable frequency drive, usually saves between 50 and 65% in electrical power costs with the same or better regulation of vacuum. The range of energy savings can be from 30 to 80 percent. They can be adapted to blower or in some cases rotary vane type vacuum pumps. They work by changing the speed of the vacuum pump predicated on the reading from a pressure sensor that’s mounted on the vacuum line near the receiver jar. The VSD is basically a dedicated computer with many adjustments so it might be possible to improve vacuum regulation over the typical pneumatic vacuum regulator that just includes a vacuum level adjustment. A VSD for a vacuum pump is usually cost-effective for a dairy that milks a complete of 8 hours or more each day. Typically a VSD will not be a cost-effective option for small dairies due to less milking time and thus shorter vacuum pump run times but there are some other options to save lots of energy costs.