System for isolating a medium voltage
View Patent ↗A signal isolating transformer may be arranged such that a first coil of the signal isolating transformer is located in a medium voltage compartment and a second coil of the signal isolating transformer is located external to the medium voltage compartment. The transformer spans an opening defined by a grounded wall to isolate faults in the medium voltage compartment.
1. A system, comprising:
a medium voltage compartment including at least one grounded wall that defines an opening;
a low voltage compartment adjacent to the wall;
a signal isolating transformer positioned within the opening and configured to electrically isolate the medium voltage compartment from the low voltage compartment, comprising:
a core having a first leg positioned within the medium voltage compartment and a second leg positioned within the low voltage compartment,
a first coil wound around the first leg,
a second coil wound around the second leg, and
a conductive plate connected to the grounded wall and the core, wherein the conductive plate is positioned between the first leg and second leg and covers the opening; and
a molded case which encapsulates the first coil, the second coil and the core and positions the first leg to one side of the conductive plate and the second leg to an opposing side of the conductive plate such that the first coil is within the medium voltage compartment and the second coil is within the low voltage compartment, wherein the molded case comprises a flange which covers the opening.
2. The system of claim 1 , wherein the metal plate is electrically bonded to the core.
3. The system of claim 1 , wherein the first coil comprises a first number of turns, a second coil comprises a second number of turns, and the first number does not equal the second number.
4. The system of claim 1 , wherein the first coil comprises a first number of turns, a second coil comprises a second number of turns, and the first number equals the second number.
5. The system of claim 1 , further comprising a tuning capacitor connected in parallel with the second coil.
6. The system of claim 1 , further comprising a tuning capacitor connected in parallel with the first coil.
7. The system of claim 1 , further comprising:
a plurality of low voltage thermostats positioned within the medium voltage compartment;
wherein the first coil is electrically connected to the thermostats.
8. The system of claim 7 , wherein the thermostats function such that opening of any of the thermostats causes impedance of the second coil to increase.
9. The system of claim 7 , further comprising:
a low voltage relay that is electrically connected to the second coil.
10. The system of claim 9 , wherein the thermostats function such that opening of any of the thermostats causes contacts of the relay to move.
11. A system, comprising:
a medium voltage compartment, wherein the medium voltage compartment includes a wall that defines an opening;
a low voltage compartment adjacent to the wall; and
a signal isolating transformer positioned within the opening and configured to electrically isolate the medium voltage compartment from the low voltage compartment, comprising:
a core having a first portion positioned within the medium voltage compartment and a second portion positioned within the low voltage compartment,
a first coil wound around the first portion of the core,
a second coil wound around the second portion of the core, and
a molded case which encapsulates the first and second coils and the core and positions the first portion to one side of the wall and the second portion to an opposing side of the wall such that the first coil is within the medium voltage compartment and the second coil is within the low voltage compartment, wherein the molded case comprises a flange which covers the opening.
12. The system of claim 11 , wherein the signal isolating transformer further comprises one or more conductive inserts electrically connected to the core inside the molded case to provide a path from the core to ground.
13. The system of claim 12 , further comprising:
a plurality of low voltage thermostats positioned within the medium voltage compartment;
wherein the first coil is electrically connected to the thermostats.
14. The system of claim 13 , wherein the thermostats function such that opening of any of the thermostats causes impedance of the second coil to increase.
15. The system of claim 14 , further comprising:
a low voltage relay that is electrically connected to the second coil.
16. The system of claim 13 , wherein the thermostats function such that opening of any of the thermostats causes contacts of the relay to move.