Low inertia direct drive drawworks

• US 10,003,229 B2
• Filed: 05/19/2016
• Issued: 06/19/2018
• Est. Priority Date: 03/13/2014
• Status: Active Grant

• Current Assignee: Nabors Drillling Technologies USA, Inc.
• Original Assignee: Nabors Drillling Technologies USA, Inc.
• Inventors: Pace, Gary, Williams, Kevin R., Garaghty, James, Ellis, Brian
• Primary Examiner(s): Buck, Matthew R
• Application Number:
  US15/159,590
• Publication Number:
  US 20160268857A1
• Time in Patent Office: 761 Days
• CPC Class Codes: B66D 1/12 incorporating electric motors
• CPC Class Codes: B66D 1/525 electrical
• CPC Class Codes: E21B 15/02 specially adapted for underwater drilling E21B15/04 takes precedence
• CPC Class Codes: E21B 19/006 including heave compensators
• CPC Class Codes: E21B 19/008 Winding units, specially adapted for drilling operations
• CPC Class Codes: E21B 19/084 with flexible drawing means, e.g. cables
• CPC Class Codes: E21B 19/09 specially adapted for drilling underwater formations from a floating support using heave compensators supporting the drill string
• CPC Class Codes: H02K 1/2706 Inner rotors
• CPC Class Codes: H02K 1/278 Surface mounted magnets; Inset magnets
• CPC Class Codes: H02K 1/30 using intermediate parts, e.g. spiders
• CPC Class Codes: H02K 1/32 with channels or ducts for flow of cooling medium

Abstract

A low inertia permanent magnet motor includes a stator and rotor. The rotor includes a generally tubular and hollow rotor body coupled to the shaft of the motor by one or more spokes and/or webs. The permanent magnets of the rotor are coupled to the rotor body. In some embodiments, the low inertia permanent magnet motor may be used to power a drawworks. In some embodiments, the drawworks may be controlled by an active heave compensation controller.

Claims

1. A low inertia permanent magnet motor comprising:

a shaft;

a stator, the stator including a plurality of windings, the windings positioned to induce a rotating electromagnetic field into the interior of the stator; and

a rotor, the rotor positioned within the stator, the rotor including a generally cylindrical, hollow rotor body and a plurality of permanent magnets, the permanent magnets coupled to the periphery of the rotor body, the rotor body coupled to the shaft only by one or more extensions extending between the rotor body and the shaft, the extensions coupled directly to the rotor body and the shaft, the rotor positioned to be rotated by the interaction of the rotating electromagnetic field induced by the stator and a permanent magnetic field of the permanent magnets.

2. The low inertia permanent magnet motor of claim 1, wherein the extensions comprise spokes, the spokes being generally linear members extending between and coupled to the shaft and the rotor body.

3. The low inertia permanent magnet motor of claim 1, wherein the extensions comprise webs, the webs being generally disk-shaped members extending between and coupled to the shaft and the rotor body.

4. The low inertia permanent magnet motor of claim 3, wherein the webs comprise cutouts formed in the webs, the cutouts reducing the weight of the webs.

5. The low inertia permanent magnet motor of claim 1, wherein the weight of the rotor body and the permanent magnets comprise between approximately 60-80% of the total weight of the rotor.

6. The low inertia permanent magnet motor of claim 1, wherein the low inertia permanent magnet motor is used to drive one of a top drive, drawworks, rack and pinion hoisting device, winch, or mud pump.