Method for operating an electrical apparatus and circuit breaker

Patent metadata

Field	Value
Publication number	US-9293288-B2
Application number	US-201213596451-A
Country	US
Kind code	B2
Filing date	Aug 28, 2012
Priority date	Aug 30, 2011
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

In order to provide a high impedance between two sensor terminals, for instance for connecting a Rogowski transducer to a circuit breaker, but to prevent the coupling-in of interference signals in the case of a non-connection to the terminals, two auxiliary terminals are connected. In at least one embodiment, they are connected in such a manner that in the basic state, the sensor terminals are short circuited but in the case of a connection, for example of a plug to the sensor terminals and simultaneously to the auxiliary terminals, the short circuit is canceled with external short circuiting of the auxiliary terminals.

First claim

What is claimed is:

1. A method for operating an electrical apparatus including two sensor terminals and two auxiliary terminals, the method comprising:
connecting a connecting element to the two auxiliary terminals to i) short circuit the two auxiliary terminals through the connecting element, and ii) increase an internal impedance provided by the electrical apparatus between the two sensor terminals.

2. The method of claim 1 , wherein, in a basic state, the apparatus short circuits the sensor terminals and when the connecting element is connected to the auxiliary terminals, the short circuit of the two sensor terminals is canceled.

3. The method of claim 1 , wherein the connecting element is a plug of a device, and if the plug is connected the two auxiliary terminals, the plug is connected simultaneously to the two sensor terminals.

4. The method of claim 1 , wherein, by short circuiting the two auxiliary terminals, a potential is changed which is present at an input of a comparator.

5. The method of claim 4 , wherein an output of the comparator is coupled to a control electrode or the gate of at least one transistor.

6. A circuit breaker, comprising:
at least one switching contact device, configured to interrupt an internal line connecting two line terminals for a line in the circuit breaker; and
a triggering device, configured to evaluate input signals, supplied to the triggering device, from current transducers to drive the at least one switching contact device based on the input signals;
a pair of auxiliary terminals and at least one pair of associated sensor terminals; and
a switching device configured to, i) in a basic state where the pair of auxiliary terminals are open, short circuit the associated pair of sensor terminals internally and, ii) in the case of the pair of auxiliary terminals being short-circuited, cancel the short circuit for the associated sensor terminals to increase an internal impedance provided by the switching device between the sensor terminals.

7. The circuit breaker of claim 6 , wherein the at least one switching contact device includes three switching contact devices wherein, in each case, one phase line with associated line terminals and sensor terminals to which, in each case, a current transducer of the circuit breaker is connected, and further comprising two additional sensor terminals configured to connect a current transducer allocated to a neutral line, outside the circuit breaker, and an additional pair of auxiliary terminals allocated to the additional sensor terminals.

8. The circuit breaker of claim 6 , wherein the switching device is configured to provide two different electrical potentials which are, in each case, coupled by a resistor to one of the pair of auxiliary terminals, and wherein one of the pair of auxiliary terminals is coupled to the input of a comparator.

9. The circuit breaker of claim 8 , wherein the output of the comparator is coupled to a control electrode or to the gate of at least one transistor.

10. The method of claim 2 , wherein the connecting element is a plug of a device, and if the plug is connected to the two auxiliary terminals, then the plug is connected simultaneously to the two sensor terminals.

11. The method of claim 2 , wherein, by short circuiting the two auxiliary terminals, a potential is changed which is present at an input of a comparator.

12. The method of claim 11 , wherein an output of the comparator is coupled to a control electrode or the gate of at least one transistor.

13. The circuit breaker of claim 7 , wherein the switching device is configured to provide two different electrical potentials which are, in each case, coupled by a resistor to one of the pair of auxiliary terminals, and wherein one of the pair of auxiliary terminals is coupled to the input of a comparator.

14. The circuit breaker of claim 13 , wherein the output of the comparator is coupled to a control electrode or to the gate of at least one transistor.

15. The circuit breaker of claim 9 , wherein the at least one transistor includes two series-connected transistors.

16. The circuit breaker of claim 14 , wherein the at least one transistor includes two series-connected transistors.

Assignees

• Fischer Andreas
• Siemens Ag

Inventors

• Fischer Andreas

Classifications

• H01H71/125 Primary

  characterised by sensing elements, e.g. current transformers (for differential protection H01H83/144) · CPC title

• Y10T307/911

  Cross-Sectional Technologies · mapped topic