Vacuum Pumps Installing a Variable Acceleration Drive (VSD), 
sometimes called a adjustable frequency drive, usually saves between 50 and 65% in electricity costs with the same or better regulation of vacuum. The range of Energy-Conserving Vacuum Pump 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 series near the receiver jar. The VSD is basically a dedicated pc with many adjustments so it may be possible to improve vacuum regulation over the typical pneumatic vacuum regulator that only has a vacuum level adjustment. A VSD for vacuum pressure pump is usually economical for a dairy that milks a complete of 8 hours or even more per day. Typically a VSD will not be an economical option for small dairies due to less milking time and therefore shorter vacuum pump run times but there are some other choices to save lots of energy costs.