Vacuum Pumps Installing a Variable Swiftness Drive (VSD), sometimes called a variable frequency drive, usually saves between 50 and 65% in electricity costs with the same or better regulation of vacuum. The range of energy savings could be from 30 to 80 percent. They may be adapted to blower or in some cases rotary vane type vacuum pumps. They function by changing the rate of the vacuum pump predicated on the reading from a pressure sensor that is mounted on the vacuum series close to the receiver jar. The VSD is actually a dedicated computer with many adjustments so it may be possible to improve vacuum regulation over the typical pneumatic vacuum regulator that only includes a vacuum level adjustment. A VSD for a vacuum pump is usually cost-effective for a dairy that milks a total of 8 hours or even more per day. Typically a VSD will not 
be an economical option for small Energy-Conserving Vacuum Pump dairies because of less milking time and therefore shorter vacuum pump run times but there are some other options to save lots of energy costs.