Energy-Conserving Vacuum Pump china vacuum Pumps Installing a Variable Velocity 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 can be from 30 to 80 percent. They may be adapted to blower or in some instances rotary vane type vacuum pumps. They function by changing the rate of the vacuum pump based on the reading from a pressure sensor that’s mounted on the vacuum line near the receiver jar. The VSD is actually a dedicated computer with many adjustments so it might be possible to improve vacuum regulation over the typical 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 total of 8 hours or even more per day. Typically a VSD will not be a cost-effective option for little dairies due to less milking period and therefore shorter vacuum pump run times but there are several other options to save lots of energy costs.