Using a variable speed drive on a farm is one way of saving on a farm’s energy expenditure. Variable speed drives are crucial for certain farm machinery such as vacuum pumps. This is because this machinery operates at full speeds for maximum capacity loads, even though the maximum capacity may not be utilized. A vacuum pump for example will work at speeds calculated for largest anticipated demand. In reality this demand is utilized for only 1% of the pumps overall operations. This leads to a waste of energy and noise pollution.