升降钻具 meaning in English

hoisting and lowering

Mechanized tripping method with ac inverter driving system and i t ' s examples is discussed
给出了交流变频驱动钻机升降钻具机械化的技术方法和实例。
Abstract : according to the load of tripping , driving system of dri ll should have rigid output performance and regulating performance approximate to constant power
文摘:根据升降钻具的负载特点，动力驱动系统必须具备的2个基本特性是硬的机械特性和近似恒功率的调速特性。