Methods and apparatus for rendering electrical cables safe
A “safe grounding apparatus” (SGA) for safely grounding or neutralizing the electrical conductors for permanent magnet motor (PMM) powered artificial lift systems and methods of practicing the same are disclosed. The SGA of the present invention ameliorates some of the dangers associated with PMM's. Methods of shorting, grounding, testing and monitoring the electrical conductors of a permanent magnet motor in order to safely manipulate the conductors are also disclosed.
1. A safe grounding apparatus for attachment to a motor lead end electrically coupled to a permanent magnet motor comprising:
the motor lead end including a plurality of electrical conductors enclosed within a layer of insulation;
a plurality of clamps adapted to pierce the layer of insulation and be selectively electrically coupled to the plurality of electrical conductors of the motor lead end;
a plurality of shorting conductors adapted to electrically couple to the clamps and extend therefrom; and
the shorting conductors adapted to electrically couple to a bus bar to electrically short the shorting conductors.
2. The safe grounding apparatus of claim 1 , wherein the motor lead end is overwrapped with a metallic armor, the apparatus further comprising a conductor adapted to electrically couple to the metallic armor and the bus bar.
3. The safe grounding apparatus of claim 2 , further comprising a grounded conductor adapted to connect to the bus bar and extend therefrom and electrically ground the shorting conductors to earth.
4. The safe grounding apparatus of claim 1 , wherein the clamps include a plurality of teeth disposed within the clamps adapted to pierce the layer of insulation and contact the electrical conductors and thereby electrically couple the power cables and the shorting conductors.
5. The safe grounding apparatus of claim 1 , further comprising the bus bar mounted within a module, the module further comprising at least one monitoring device adapted to monitor at least one condition of the motor lead end and the permanent magnet motor.
6. The safe grounding apparatus of claim 5 , wherein the at least one monitoring device measures a voltage, a current or an impedance.
7. The safe grounding apparatus of claim 6 , wherein the module includes a display, an indicator or an annunciator coupled to the at least one monitoring device.
8. The safe grounding apparatus of claim 6 , wherein the at least one condition includes a speed of the permanent magnet motor.
9. The safe grounding apparatus of claim 1 , wherein the shorting conductors coupled to the bus bar is adapted to produce a braking torque in the permanent magnet motor.
10. A method for rendering a motor lead end coupled to a permanent magnet motor safe, the method comprising:
providing a plurality of clamps;
selectively electrically coupling the clamps to a plurality of electrical conductors of a plurality of power cables of the motor lead end;
electrically coupling the clamps to a plurality of shorting conductors;
electrically coupling the shorting conductors to a bus bar; and
monitoring at least one condition of at least one of the motor lead end and the permanent magnet motor.
11. The method of claim 10 , further comprising electrically grounding the shorting conductors to earth.
12. The method of claim 10 , wherein the electrical conductors include an insulation, the method further comprising the clamps piercing the insulation contacting the electrical conductors and thereby electrically coupling the power cables and the shorting conductors.
13. The method of claim 10 , wherein the at least one condition includes a current, a voltage, or an impedance.
14. The method of claim 10 , further including displaying, indicating or annunciating a condition related to the at least one condition.
15. The method of claim 10 , wherein the plurality of power cables are overwrapped by a metallic armor, the method further comprising electrically coupling the metallic armor to the shorting conductors shorting the metallic armor.
16. The method of claim 10 , wherein electrically coupling the shorting conductors to the bus bar produces a braking torque in the permanent magnet motor.
17. The method of claim 10 further comprising terminating the motor lead end at an uphole end such that the plurality of clamps are positioned between the uphole end and the permanent magnet motor.
18. The method of claim 17 further comprising preparing the motor lead end for splicing after the terminating step.
19. The method of claim 17 , wherein the terminating step comprises sawing the motor lead end.
20. The method of claim 10 , wherein the monitoring at least one condition comprises determining if a hazard is present.
21. The method of claim 20 , wherein the hazard comprises a shock, a sparking, or an earth fault.