... device. While for hoister, drill pump, and drum, all adopt independent electric driving, infinite speed regulation ... , (for the drum, the compound driving is also available); and the oil derrick is designed with ... electromagnetic eddy current device etc, for hoister, drum, drill pump, all adopt unified driving; the ... 1000,000) Lifting System Rope Tied System4×55×66×7 Diameter of the Lifting Steel ...