Importance

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Abstract

The system and method for use with a drawworks having a rotatable drum on which a line is wound, wherein the drawworks and the line are used for facilitating movement of a load suspended on the line, includes a drawworks control system for monitoring and controlling the drawworks. A brake arrangement is connected to the rotatable drum for limiting the rotation of the rotatable drum and at least one electrical motor is connected to the rotatable drum for driving the rotatable drum. A load signal representative of the load on the line is produced and a calculated torque value based on the load signal and electrical motor capacity is provided. The drawworks control system provides a signal representative of the calculated torque value to the electrical motor wherein pre-torquing is generated in the electrical motor in response to the signal. Control of the rotation of the rotatable drum is transferred from the brake arrangement to the electrical motor when the electrical motor pre-torquing level is substantially equal to the calculated torque value.

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First Claim