(Photo courtesy of Wirtgen Group)
Hamm’s completely battery-electric driven tandem rollers are designed to complement the company’s HD CompactLine series. Some models are equipped with oscillation drums, including E-combination rollers with oscillation. They are not only compact emission-free but are also quiet.
With eight electric rollers in the compact class, Hamm’s HD 10e model has a drum width of 1.00 m (39.4”) and an operating weight of 2.5 t (5,512 lb.), while the HD 12e model has a drum width of 1.20 m (47.2”) and an operating weight of 2.7 t (5,953 lb.). The electric rollers have the same compaction power as their combustion engine counterparts but produce zero local emissions. They are also operated in almost the same way as the other models in the HD CompactLine series.
The machines feature a 48V Li-ion battery with 23.4 kWh capacity to provide the energy for driving, steering and dynamic compaction. Charging from zero to 100 per cent takes approximately four hours on 220V, reports the manufacturer. The roller is designed to operate in ambient temperatures of up to 113°F.
The vibration or oscillation unit is driven by electric means only via specially designed, compact synchronous motors. This results in an efficiency rating of more than double, and the energy demand reduces accordingly, as well. The electric drive motor and steering motor power a hydraulic system. All e-components require no maintenance and offer impressively high torque, and a large portion of the braking energy is fed back into the system by means of regeneration.
The company’s HAMMTRONIC control system monitors and controls the components of the zero-emissions rollers. Combined with the electronic driving levers, Hamm says this makes the machine extremely easy to control with precision. Speed ramping is also implemented to ensure smooth accelerating and braking maneuvers.
Four of the e-models feature oscillation drums, two of which are combination rollers. With quiet oscillation meeting a quiet e-drive, the compaction machines produce no emissions and cause very few vibrations in the surrounding area. As such, they are ideal for compacting in noise-sensitive and vibration-sensitive areas, such as near hospitals or historical buildings.
