Apparatus and method of blocking and unblocking a breaker handle of a circuit breaker

Patent metadata

Field	Value
Publication number	US-9685293-B1
Application number	US-201615131717-A
Country	US
Kind code	B1
Filing date	Apr 18, 2016
Priority date	Apr 18, 2016
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

An apparatus and a method are provided to block and unblock a breaker handle of a circuit breaker having main contacts. The apparatus comprises a locking mechanism including a locking handle shaft and a locking latch. The locking handle shaft is configured to latch the locking mechanism for keeping the breaker handle in a mid-position in which the main contacts stay open. The locking handle shaft has a latching surface configured to be removed from its position in order to rotate the breaker handle to a fully ON position in which the main contacts fully close. The locking latch is configured to prevent rotation of the locking handle shaft. The locking latch is configured to engage and disengage with the locking handle shaft in order to rotate the breaker handle from a reset position to the mid-position in which the locking mechanism locks the breaker handle rotation thus preventing the main contacts from closing. The breaker handle is stopped at the mid-position by the locking mechanism until a self-test is passed.

First claim

What is claimed is:

1. An apparatus to block and unblock a breaker handle of a circuit breaker having main contacts, the apparatus comprising:
a locking mechanism including:
a locking handle shaft configured to latch the locking mechanism for keeping the breaker handle in a mid-position in which the main contacts stay open, the locking handle shaft having a latching surface configured to be removed from its position in order to rotate the breaker handle to a fully ON position in which the main contacts fully close; and
a locking latch is configured to prevent rotation of the locking handle shaft, wherein the locking latch is configured to engage and disengage with the locking handle shaft in order to rotate the breaker handle from a reset position to the mid-position in which the locking mechanism locks the breaker handle rotation thus preventing the main contacts from closing, wherein the breaker handle is stopped at the mid-position by the locking mechanism until a self-test is passed.

2. The apparatus of claim 1 , wherein the locking latch is configured to rotate the breaker handle to an Over Center to ON (OC-ON) position in which the locking mechanism unlocks the breaker handle rotation thus moving the main contacts to close and then to rotate the breaker handle to the fully ON position.

3. The apparatus of claim 2 , wherein the locking mechanism further includes:
a solenoid with a plunger configured to disengage the locking handle shaft and the locking latch to de-latch the locking mechanism by forcing the rotation of the locking latch to rotate clockwise once triggered for rotating the breaker handle from the mid-position to the Over Center to ON (OC-ON) position.

4. The apparatus of claim 3 , wherein the locking handle shaft is configured to de-latch before the breaker handle rotates counterclockwise to the fully ON position from the Over Center to ON (OC-ON) position of the breaker handle allowing the main contacts to fully close.

5. The apparatus of claim 3 , wherein the locking mechanism further includes:
a handle switch and an actuating lever to activate the handle switch during rotation of the breaker handle and de-activate the handle switch when the breaker handle is rotated to the fully ON position.

6. The apparatus of claim 5 , wherein the breaker handle having an extended tab to contact a surface of the handle switch to close a test circuit for performing the self-test to verify whether an Arc and/or Ground fault detection circuitry of the circuit breaker is working properly.

7. The apparatus of claim 1 , wherein the locking handle shaft having a stop and the locking latch defines a latching lever such that when the breaker handle is moved to the reset position the latching lever is rotated counterclockwise and the latching lever stops against the stop of the locking handle shaft.

8. The apparatus of claim 1 , wherein the locking latch is configured to rotate about a pivot.

9. The apparatus of claim 1 , wherein the locking handle shaft having a recess that interfaces with an extended tab of a breaker handle tie bar to latch the locking mechanism.

10. The apparatus of claim 1 , wherein the locking mechanism further includes:
an integrated return torsion spring for the locking latch.

11. The apparatus of claim 1 , wherein the locking mechanism further includes:
a driving-counterclockwise feature to rotate the locking handle shaft counterclockwise; and
a return-clockwise feature to rotate the locking handle shaft clockwise.

12. A circuit breaker having main contacts, the circuit breaker comprising:
a breaker handle; and
first, second, and third modules, wherein the second module is disposed in between the first and third modules, wherein the second module including:
a locking mechanism to block and unblock the breaker handle of the circuit breaker, the locking mechanism including:
a locking handle shaft configured to latch the locking mechanism for keeping the breaker handle in a mid-position in which the main contacts stay open, the locking handle shaft having a latching surface configured to be removed from its position in order to rotate the breaker handle to a fully ON position in which the main contacts fully close, and
a locking latch configured to prevent rotation of the locking handle shaft, wherein the locking latch is configured to engage and disengage with the locking handle shaft in order to rotate the breaker handle from a reset position to the mid-position in which the locking mechanism locks the breaker handle rotation thus preventing the main contacts from closing, wherein the breaker handle is stopped at the mid-position by the locking mechanism until a self-test is passed.

13. The circuit breaker of claim 12 , wherein the locking latch to rotate the breaker handle to an Over Center to ON (OC-ON) position in which the locking mechanism unlocks the breaker handle rotation thus moving the main contacts to close and then to rotate the breaker handle to the fully ON position.

14. The circuit breaker of claim 13 , wherein the locking mechanism further includes:
a solenoid with a plunger configured to disengage the locking handle shaft and the locking latch to de-latch the locking mechanism by forcing the rotation of the locking latch to rotate clockwise once triggered for rotating the breaker handle from the mid-position to the Over Center to ON (OC-ON) position.

15. The circuit breaker of claim 14 , wherein the locking handle shaft is configured to de-latch before the breaker handle rotates counterclockwise to the fully ON position from the Over Center to ON (OC-ON) position of the breaker handle allowing the main contacts to fully close.

16. The circuit breaker of claim 14 , wherein the locking mechanism further includes:
a handle switch and an actuating lever to activate the handle switch during rotation of the breaker handle and de-activate the handle switch when the breaker handle is rotated to the fully ON position.

17. The circuit breaker of claim 16 , wherein the breaker handle having an extended tab to contact a surface of the handle switch to close a test circuit for performing the self-test to verify whether an Arc and/or Ground fault detection circuitry of the circuit breaker is working properly.

18. The circuit breaker of claim 12 , wherein the locking handle shaft having a stop and the locking latch defines a latching lever such that when the breaker handle is moved to the reset position the latching lever is rotated counterclockwise and the latching lever stops against the stop of the locking handle shaft.

19. A method of blocking and unblocking a breaker handle of a circuit breaker having main contacts, the method comprising:
latching using a locking handle shaft a locking mechanism that blocks and unblocks the breaker handle for keeping the breaker handle in a mid-position in which the main contacts stay open, the locking handle shaft having a latching surface configured to be removed from its position in order to rotate the breaker handle to a fully ON position in which the main contacts fully close;
preventing using a locking latch rotation of the locking handle shaft, wherein the locking latch is configured to engage and disengage with the locking handle shaft in order to rotate the breaker handle from a reset position to the mid-position in which the locking mechanism locks the breaker handle rotation thus preventing the main contacts from closing; and
stopping the breaker handle at the mid-position by the locking mechanism until a self-test is passed.

2

Assignees

• Siemens Industry Inc

Inventors

• Watford Russell Thomas

Classifications

• H01H71/1054 Primary

  Means for avoiding unauthorised release · CPC title

• H01H83/14

  operated by imbalance of two or more currents or voltages, e.g. for differential protection · CPC title

• H01H71/123

  using a solid-state trip unit (circuits H02H) · CPC title

• H01H2083/201

  the other abnormal electrical condition being an arc fault · CPC title

• H01H71/62

  with means for preventing resetting while abnormal condition persists, e.g. loose handle arrangement · CPC title