Disc chipper for crushing lumpy feed material, particularly wood

A disc chipper for the comminution of lumpy feed material, the disc chipper comprising:

• a crushing rotor driven by a drive unit and rotating about an axis;
• a rotor shaft;
• a chipping disc connected in a rotationally fixed manner with the rotor shaft, the chipping disc having chipping knives that are transversely aligned in the disc plane to the rotational direction and that cooperate with stationary counter knives for the comminution of the feed material;
• and
• the drive unit including a primary drive and a secondary drive, which drive the crushing rotor via a transmission, the primary drive being in active operative connection with the crushing rotor during a crushing operation and the secondary drive being in active operative connection with the crushing rotor during an acceleration process,
• wherein the primary drive comprises an electric motor, and
• wherein the secondary drive accelerates the chipping disc to a rotational speed at which the disc chipper is to be operated during the crushing operation.