The Volvo DD118HF and the DD138HF compactors increase production through a high frequency design. Both compactors employ the SMART start system, available only on Volvo compactors. A consistent mat quality and density is achieved through this system. The Volvo impact meter measures the relationship between the compactor’s vibration frequency and its rolling speed to accurately indicate the number of drum impacts per foot. The DD118HF has a Cummins four-cylinder engine and the DD138HF has a Cummins six-cylinder engine. The DD118HF has a vibration frequency of 3,400 vibrations per minute (56.67 hertz), a maximum centrifugal force of 42,680 pounds (190 kN) and a maximum nominal amplitude of 0.025 inches (0.63 millimetres). The DD138HF has a vibration frequency of 3,200 vibrations per minute (53.3 hertz), a maximum centrifugal force of 42,260 pounds (188 kN) and a maximum nominal amplitude of 0.025 inches (0.63 millimetres).
