Overhead line winches KW 3F and KW 4F
Overhead line construction demands a maximum of reliability and operating precision of the winches used. To remove the fixing clamps of the insulators, the cable has to be lifted exactly to a point where the insulators are relieved from the cable load, but at the same time are no longer pressed against the fittings. Until the insulators are disconnected, the cable has to be lowered at a precisely controlled rate. This requires precise control and freedom of jerks. Any jerk of the cable may endanger the safety and life of the men high up in the pylon.
Thanks to the automatic hold-on (static pull) system, the overhead cable can be held in any desired position by means of the pulling force preselector. At the point where the insulator can be freely moved, the hydraulically controlled multiple disk brake is put on. As soon as the insulators are removed, the winch is put in reverse and starts running against the hydraulic load brake. Balancing the pressure of the hydraulic pump and the action of the load brake precisely controls the cablelowering rate.
The overhead line winch of Type KW 3F is equipped with a electronic printer and may also be used for pulling underground cables without the need for any refitting.