... stepless variable frequency driven.Main components/parts,such as a crown block,traveling block,hook,swivel, rotary table,mast & substructure are in ... the drilling automation, the drilling rig is equipped with a hydraulic disc brake and some mechanized wellhead tools to ... .as required, drilling floor can be the structure of block assembled or self-propelled. ParametersModelZJ40/2250 D/DB/L/LDBNominal ...