Dry Tests of Vacuum Stability in Milking Machines with Conventional Regulators and Adjustable Speed Vacuum Pump Controllers

A survey of vacuum control, noise levels and energy savings was performed on 15 farms in Lombardia, Italy comparing conventional vacuum regulation systems with variable speed drive (VSD) control systems on each milking machine. The data showed that if VSD controllers are set up properly they are able to meet or exceed the vacuum stability of conventional regulators. The reduction in noise levels achieved by VSD control systems averaged about 12 dB with up to 24 dB reductions in some locations. The energy saved by using VSD controllers was considerable, averaging 56%, with up to 87% savings observed on larger systems. VSD controllers also reduce the starting current of large electric motors, which may be a significant advantage when operated on some rural power distribution systems.