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 could 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 speed of the vacuum pump predicated on the reading from a pressure sensor that is installed on the vacuum series close to the receiver jar. The VSD is basically a dedicated pc with many adjustments therefore it could be possible to improve vacuum regulation over the normal 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 total of 8 hours or more each day. Typically a VSD will not be a cost-effective option for small Energy-Conserving Vacuum Pump dairies because of less milking time and therefore shorter vacuum pump operate times but there are several other choices to save lots of energy costs.