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. An apparatus for attachment to a plurality of power cables electrically coupled to a permanent magnet motor comprising:
a plurality of clamps selectively electrically coupled to a plurality of electrical conductors of the power cables, wherein the plurality of power cables are overwrapped by a metallic armor;
a plurality of shorting conductors electrically coupled to the clamps and extending therefrom;
the shorting conductors electrically coupled to a bus bar electrically shorting the shorting conductors; and
a conductor electrically coupled to the metallic armor and the bus bar.
2. The apparatus of claim 1 , further comprising a grounded conductor connected to the bus bar and extending therefrom and electrically grounding the shorting conductors to earth.
3. The apparatus of claim 1 , wherein at least one of the power cables or at least one of the shorting conductors includes an insulation wherein the shorting conductors are enclosed within the insulation, a plurality of teeth disposed within the clamps piercing the insulation and contacting the electrical conductors and thereby electrically coupling the power cables and the shorting conductors.
4. The apparatus of claim 1 , wherein electrically shorting the shorting conductors produces a braking torque in the permanent magnet motor.
5. An apparatus for attachment to a plurality of power cables electrically coupled to a permanent magnet motor comprising:
a plurality of clamps selectively electrically coupled to a plurality of electrical conductors of the power cables;
a plurality of shorting conductors electrically coupled to the clamps and extending therefrom;
the shorting conductors electrically coupled to a bus bar electrically shorting the shorting conductors; and
a module having the bus bar mounted therein, the module further comprising at least one monitoring device monitoring at least one condition of the permanent magnet motor.
6. The apparatus of claim 5 , wherein the at least one monitoring device measures a voltage, a current or an impedance.
7. The apparatus of claim 5 , wherein the module includes a display, an indicator or an annunciator coupled to the at least one monitoring device.
8. The apparatus of claim 5 , wherein the at least one condition includes a speed of the permanent magnet motor.
9. A method for safely working with a plurality of power cables, the method comprising:
coupling a first end of the plurality of power cables of a motor lead end to a permanent magnet motor;
providing a plurality of clamps;
selectively electrically coupling the clamps to a plurality of electrical conductors of a second end of the power cables;
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 the permanent magnet motor.
10. The method of claim 9 , further comprising electrically grounding the shorting conductors to earth.
11. The method of claim 9 , wherein at least one of the power cables and the conductors includes an insulation wherein the shorting conductors are enclosed within the insulation, the method further comprising the clamp piercing the insulation contacting the electrical conductors and thereby electrically coupling the power cables and the shorting conductors.
12. The method of claim 9 , wherein the at least one condition includes a current, a voltage, or an impedance.
13. The method of claim 9 , further including displaying, indicating or annunciating a condition related to the at least one condition.
14. The method of claim 9 , 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.
15. The method of claim 9 , further comprising producing a braking torque in the permanent magnet motor.
16. The method of claim 9 further comprising splicing the second end of the motor lead to a plurality of conductors of a power cable.
17. The method of claim 16 wherein the conductors of the power cable are comprised of an electrical conductor disposed within an insulation layer, the method further comprising:
terminating the second end of the motor lead and an end of the power cable;
exposing the insulated conductors of the second end of the motor lead and the power cable;
stripping a portion of the insulating jacket from the terminated ends of the insulated conductors exposing a portion of the electrical conductors;
electrically splicing the electrical conductors of the motor lead to the electrical conductors of the power cable; and
one-by-one decoupling one of the shorting conductors from one of the insulated electrical conductors and encapsulating the splice and a portion of the insulating jacket in an insulating material.
18. The method of claim 17 , wherein terminating comprises sawing.
19. The method of claim 9 , further comprising interrupting the method if a hazard is present.
20. The method of claim 19 , wherein the hazard comprises a shock, a sparking, or an earth fault.