| 摘要 |
In the case of rotating mechanism drives for large jibs of ships, excavators or cranes having gearwheel transmission, as a rule, the tooth system is not designed very precisely. Unless any special protective measures are adopted, there is thus play between the tooth edges between motor-driven pinions and a rotating mechanism toothed rim, which play has a disturbing effect as looseness during rotation of the jib and, when it is at rest, as a result of wind forces and rolling on ships and can lead to fatigue fractures of teeth or to damage to the jib structure. In order to overcome this looseness, at least two drive machines (M1, M2) (which act via pinions on the rotating mechanism toothed rim) are electrically braced with respect to one another, in that bracing currents which have different directions and magnitudes and correspond to the different bracing torques, are superimposed (iM1, iM2) on the armature currents which correspond to load torques which can be predetermined, so that different torques are transmitted by at least two drive machines. The sum of all the bracing torques acting on the rotating mechanism toothed rim is approximately zero. A DC drive (M1, M2) having rotation speed regulation (1, 2) and lower-ranking current regulation (8, 9) is used, in the case of which a different required bracing current value signal ( DELTA i1, DELTA i2) is added to a required current signal (isoll) at the output of one rotation speed regulator (2) per regulating system for each DC machine (M1, M2). The required current signal formed in this way must not exceed required current limiting values (+/-imax1, +/-imax2) which can be predetermined. In order to protect the transmission during a torque zero crossing for the respective DC machine, the required current is reduced for a time period which can be predetermined, by means of changeover logic (14) and a required current level control element (7). <IMAGE>
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