Circuit interrupter and receptacle with temperature based trip

Patent metadata

Field	Value
Publication number	US-10622169-B2
Application number	US-201715716846-A
Country	US
Kind code	B2
Filing date	Sep 27, 2017
Priority date	Sep 27, 2017
Publication date	Apr 14, 2020
Grant date	Apr 14, 2020

Abstract

A circuit interrupter includes separable contacts, a trip actuator structured to cause the separable contacts to trip open, a conductor structured to carry power through the circuit interrupter, a sensor having a forward bias voltage drop inversely proportional to temperature and being disposed proximate the conductor, an amplifier circuit electrically connected to the sensor and being structured to amplify the forward bias voltage drop of the sensor, and a comparator circuit structured to compare the amplified forward bias voltage drop with a predetermined reference voltage and to output a signal to the trip actuator when the amplified forward bias voltage drop is less than or equal to the predetermined reference voltage. The signal causes the trip actuator to cause the separable contacts to trip open.

First claim

What is claimed is:

1. A circuit interrupter comprising:
separable contacts;
a trip actuator structured to cause the separable contacts to trip open;
a conductor structured to carry power through the circuit interrupter;
a sensor having a forward bias voltage drop inversely proportional to temperature and being disposed proximate and thermally coupled to the conductor;
an amplifier circuit electrically connected to the sensor and being structured to amplify the forward bias voltage drop of the sensor;
a comparator circuit structured to compare the amplified forward bias voltage drop with a predetermined reference voltage and to output a signal to the trip actuator when the amplified forward bias voltage drop is less than or equal to the predetermined reference voltage;
a power supply structured to receive an alternating current voltage and to convert the alternating current voltage to a direct current voltage as a supply voltage for the circuit interrupter; and
a voltage regulator circuit structured to output an enable signal to activate the comparator circuit when the supply voltage provided by the power supply stabilizes,
wherein the signal causes the trip actuator to cause the separable contacts to trip open.

2. The circuit interrupter of claim 1 , wherein the sensor is a diode having a P-N junction and the forward bias voltage drop is a voltage drop across the P-N junction.

3. The circuit interrupter of claim 1 , wherein the sensor is a bi-polar junction transistor having a P-N junction and the forward bias voltage drop is a voltage drop across the P-N junction.

4. The circuit interrupter of claim 1 , wherein the forward bias voltage drop of the sensor is inversely proportional to temperature at a predetermined rate of voltage drop per degree Celsius.

5. The circuit interrupter of claim 1 , wherein the amplifier includes first, second, and third resistors, a potentiometer, and a transistor; wherein the potentiometer is electrically connected between a base of the transistor and the sensor; wherein the first resistor is electrically connected between the base of the transistor and a supply voltage; wherein the second resistor is electrically connected between the supply voltage and a collector of the transistor; wherein the third resistor is electrically connected between an emitter of the transistor and ground; and wherein the collector of the transistor is electrically connected to the comparator.

6. The circuit interrupter of claim 1 , wherein the comparator circuit includes first, second, and third resistors and first, second, and third transistors; wherein the first resistor is electrically connected between emitters of the first and second transistors and ground; wherein the second resistor is electrically connected to a base of the third transistor and a collector of the first transistor; wherein the third resistor is electrically connected to an emitter of the third transistor; wherein the base of the first transistor is structured to receive the amplified forward bias voltage drop and a base of the second transistor is structured to receive the predetermined reference voltage; and wherein the comparator circuit is structured to output the signal through the third resistor.

7. The circuit interrupter of claim 1 , wherein the comparator circuit includes a resistor and first and second transistors; wherein the resistor is electrically connected to emitters of the first and second transistors; wherein a base of the first transistor is structured to receive the amplified forward bias voltage drop; wherein a base of the second transistor is structured to receive the predetermined reference voltage; and wherein the comparator circuit is structured to output the signal through a collector of the second transistor.

8. The circuit interrupter of claim 1 , wherein the voltage regulator circuit includes a resistor, a zener diode, and a transistor; wherein the resistor is electrically connected between the supply voltage and a base of the transistor; wherein the zener diode is electrically connected between ground and the base of the transistor; wherein an emitter of the transistor is electrically connected to the supply voltage; and wherein a collector of the transistor is electrically connected to the comparator and is structured to output the activation signal.

9. The circuit interrupter of claim 1 , wherein the trip actuator includes a silicon controlled rectifier and a solenoid; wherein the trip actuator is structured to receive the signal at a gate of the silicon controlled rectifier; and wherein the silicon controlled rectifier is structured to activate and allow current to flow through the solenoid in response to receiving the signal.

10. The circuit interrupter of claim 1 , wherein the sensor includes a plurality of diodes or transistors electrically connected in parallel.

11. The circuit interrupter of claim 1 , wherein the circuit interrupter is a circuit breaker having a conductive path therethrough; and wherein the sensor is disposed proximate and thermally coupled to the conductive path.

12. The circuit interrupter of claim 11 , further comprising:
an input terminal disposed on the conductive path; and
an output terminal disposed on the conductive path,
wherein the sensor is disposed proximate and thermally coupled to one of the input terminal and the output terminal.

13. A circuit interrupter comprising:
separable contacts;
a trip actuator structured to cause the separable contacts to trip open;
a conductor structured to carry power through the circuit interrupter;
a sensor having a forward bias voltage drop inversely proportional to temperature and being disposed proximate and thermally coupled to the conductor;
an amplifier circuit electrically connected to the sensor and being structured to amplify the forward bias voltage drop of the sensor;
a comparator circuit structured to compare the amplified forward bias voltage drop with a predetermined reference voltage and to output a signal to the trip actuator when the amplified forward bias voltage drop is less than or equal to the predetermined reference voltage,
wherein the signal causes the trip actuator to cause the separable contacts to trip open,
wherein the circuit interrupter is a circuit breaker having a conductive path therethrough, and wherein the sensor is disposed proximate and thermally coupled to the conductive path, and
wherein the circuit interrupter further comprises:
an input terminal disposed on the conductive path;
an output terminal disposed on the conductive path, wherein the sensor is disposed proximate and thermally coupled to one of the input terminal and the output terminal; and and
a resistive element disposed on the conductive path,

wherein the sensor is disposed proximate and thermally coupled to the resistive element.

14. The circuit interrupter of claim 12 , wherein the circuit interrupter does not include a bimetallic element.

15. A receptacle comprising:
separable contacts;
a trip actuator structured to cause the separable contacts to trip open;
an outlet structured to electrically connect to a load;
a conductor structured to carry power through the receptacle;
a sensor having a forward bias voltage drop inversely proportional to temperature and being disposed proximate and thermally coupled to the conductor;
an amplifier circuit electrically connected to the sensor and being structured to amplify the forward bias voltage drop of the sensor;
a comparator circuit structured to compare the amplified forward bias voltage drop with a predetermined reference voltage and to output a signal to

Assignees

• Eaton Corp
• Eaton Intelligent Power Ltd

Inventors

• Schmalz Steven Christopher
• Zhou Xin

Classifications

• H02H3/085

  making use of a thermal sensor, e.g. thermistor, heated by the excess current (also responsive to the temperature of the protected device H02H5/041, thermal images H02H6/00) · CPC title

• H01H71/125 Primary

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

• H01H9/54 Primary

  Circuit arrangements not adapted to a particular application of the switching device and for which no provision exists elsewhere · CPC title

• H01H73/20

  Terminals; Connections · CPC title

• H01H71/14

  Electrothermal mechanisms {(combined with a electro-thermal time delay relay H01H61/002)} · CPC title