# US 10,483,751 B2 · Trip control circuit for circuit breaker > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,483,751 B2 - Document ID: US10483751B2 - Status: Granted - Kind: B2 - Application number: 15/495,913 - Filed: 2017-04-24 - Published: 2017-11-02 - Granted: 2019-11-19 - Earliest claimed: 2016-04-28 - Assignees: Lsis Co., Ltd. - Applicants: Lsis Co., Ltd. - Inventors: Jongkug Seon - Web page: https://patentgrep.com/patent/US10483751B2 ## CPC - G01R 31/52: Testing for short-circuits, leakage current or ground faults - G01R 15/183: {using transformers with a magnetic core} - G01R 19/10: Measuring sum, difference or ratio - G01R 19/16538: {in AC or DC supplies (G01R19/16519 and G01R19/16528 take precedence)} - H01H 83/226: {with differential transformer} - H02H 1/0007: {concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445)} - H02H 3/08: responsive to excess current (responsive to abnormal temperature caused by excess current H02H5/04) - H02H 3/087: for DC applications - H02H 3/16: responsive to fault current to earth, frame or mass (with balanced or differential arrangement H02H3/26 {; monitoring earth connection H02H5/105}) - H02H 3/332: {with means responsive to DC component in the fault current} - B60L 3/0069: {relating to the isolation, e.g. ground fault or leak current} - G01R 19/0015: {separating AC and DC} - G01R 19/165: Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values - H01F 38/28: Current transformers - H01F 38/305: {with toroidal magnetic core} - H01H 83/144: {with differential transformer} - H02H 3/165: {for three-phase systems} - H02H 3/33: using summation current transformers (H02H3/347 takes precedence) - H02H 3/347: using summation current transformers - H02H 3/44: responsive to the rate of change of electrical quantities - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - H01H: ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES (contact cables H01B7/10; electrolytic self-interrupters H01G9/18; emergency protective circuit arrangements H02H; switching by electronic means without contact-making H03K17/00) - H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H) - B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES ## Abstract The present invention provides a trip control circuit for a circuit breaker capable of breaking a circuit when a fault current occurs due to a DC current component, as well as an AC current. The trip control circuit comprises a current transformer that has a core allowing a circuit to pass through and a secondary coil for detecting a current flowing on the circuit and providing a current detection signal; an oscillation circuit section that configured to apply an electrical signal to the secondary coil to increase a slope of a hysteresis loop of the current transformer to allow the secondary coil to detect a DC current and an AC current; and a trip determining circuit section that configured to compare a current value indicated by the current detection signal with a predetermined reference current value. ## Claims ### Claim 1 A trip control circuit for a circuit breaker, the trip control circuit comprising: a current transformer that has a ring-shaped core allowing a circuit to pass through and a secondary coil wound around the core for detecting a current flowing on the circuit and providing a current detection signal; an oscillation circuit section that is configured to apply an electrical signal to the secondary coil of the current transformer to increase a slope of a hysteresis loop of the current transformer to allow the secondary coil to detect a DC current, as well as an AC current, flowing on the circuit; and a trip determining circuit section that is configured to compare a current value indicated by the current detection signal having an AC component and a DC component output from the secondary coil of the current transformer with a predetermined reference current value, and output a trip control signal when the current value indicated by the current detection signal exceeds the reference current value, and wherein the trip determining circuit section is configured to determine a current amount flowing on the circuit according to a change in time on the basis of the current detection signal, and determine a waveform and a frequency of the electrical signal to be supplied to the secondary coil through the oscillation circuit section. ### Claim 2 (depends on 1) The trip control circuit of claim 1, further comprising a sensing resistor connected to the secondary coil of the current transformer that converts a current signal as a current detection signal provided by the secondary coil into a voltage signal, and outputs the converted voltage signal. ### Claim 3 (depends on 1) The trip control circuit of claim 1, wherein the electrical signal applied by the oscillation circuit section is configured with a square wave signal. ### Claim 4 (depends on 1) The trip control circuit of claim 1, wherein the electrical signal applied by the oscillation circuit section is configured with a sine wave signal having high frequency. ### Claim 5 (depends on 1) The trip control circuit of claim 1, wherein the trip determining circuit section is configured to determine a signal of a waveform to be output by the oscillation circuit section on the basis of a relationship between a change in a magnetic field intensity generated in the secondary coil as time passed and a change in a magnetic flux density corresponding thereto. ### Claim 6 (depends on 1) The trip control circuit of claim 1, further comprising a first display unit that displays a magnetic flux density and a magnetic field intensity of the secondary coil corresponding to a signal applied by the oscillation circuit section to the secondary coil. ### Claim 7 (depends on 1) The trip control circuit of claim 1, further comprising a second display unit that is configured to display an information indicating that a DC component is detected, when the DC component flowing on the circuit passing through the core of the current transformer is detected. ### Claim 8 (depends on 1) The trip control circuit of claim 1, wherein the trip determining circuit section is configured to receive a current detection signal from the secondary coil which has detected a current including at least one of a DC current component and an AC current component flowing on the circuit or a mixed current of the DC current and the AC current. ### Claim 9 (depends on 1) The trip control circuit of claim 1, wherein the trip determining circuit section comprises a low pass filter circuit section that removes a high frequency signal that may be mixed in the current detection signal for a current induced to the secondary coil.