Liebherr presents two new electric excavators. The R 976-E electric crawler excavator, together with the R 980 SME-E, succeeds the ER 974 B in mining and quarrying applications.
The latest electric excavators, developed by Liebherr-France in Colmar, France, are more than a simple adaptation of a diesel-engined excavator. Development and electrification were completely designed and implemented by Liebherr.
The electrical system of the new Liebherr crawler excavator R 976-E with 400 kW is supplied with an operating voltage of 6,000 V via a cable, the input of which is located in the middle of the undercarriage or, if desired, on the sides. A cable drum is also available as an option. The 6,000 V/50 Hz power supply is provided by a high-voltage slip-ring collector. A transformer switch cabinet (high voltage/low voltage), as well as a low-voltage switch cabinet for the distribution and control of the on-board voltages of 690 V, 230 V and 24 V, are located on the superstructure.
The low-voltage asynchronous electric motor installed on the R 976-E drives the hydraulic system. The motor has heat protection on the bearings and windings and is integrated into a frame with a reinforced flange and enables a fused soft start. The two robust control cabinets are made of a special machine-welded structure designed to withstand extreme working conditions.The high-voltage control cabinet is for the power connector and the transformation of the electrical voltage, while the low-voltage control cabinet monitors the connection. Liebherr does not provide technical details on the R 980 SME-E.
The integrated technology in the R 976-E and R 980 SME-E models is said to offer numerous advantages. “Thanks to its constant speed whatever the load, an excavator with an electric engine has a longer service life. Also, the high availability of transient power for complex machine movements enables very high productivity,” Liebherr says.