دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: see chain drive. chain-and-sprocket drive n: a type of drive that consists of a loop of chain that goes around two shafts with sprockets fitted on the shafts. The driving shaft provides power and the driven shaft receives power. When the sprocket on the driving shaft turns, the chain moves and turns the driven sprocket. chainand- sprocket transmission n: a selective transmission made up primarily of chain-andsprocket drives. There are three two-strand chain-and-sprocket drives and a pair of gears for reversing, located between the input shaft coming from the compound, and the output shaft on a mechanically driven drawworks. Each of these chain-and- sprocket drives has a different sprocket ratio to provide three speeds to the high-drum drive and three to the low-drum drive. Com- pare gear transmission.

n: once the drawworks receives power from either the compound or electric motors, the type of transmission that allows the driller to select how the power is distributed (torque! speed combinations) to various components of the drawworks. The drawworks on both mechanical-drive and electric-drive rigs have a selective transmission.