High-voltage circuit-breaker diagnostics: timing, contact resistance, coils and SF6
Enter your HV circuit-breaker measurements and get the status per test and subsystem, the likely cause and an action plan to IEC 62271 or IEEE C37.
Diagnose your high-voltage circuit-breaker Enter the nameplate data and field measurements (timing, travel, contact resistance, coils, SF6 and insulation) and get the status per test and per subsystem, the likely cause and an action plan to IEC 62271 or IEEE C37, with a report to print or download. Diagnose my circuit-breaker Close the diagnosis
What this tool does
It assesses a high-voltage circuit-breaker from the field measurements you enter and returns:
- The verdict: pass, pass with remarks, fail or critical, with the corresponding action and its priority.
- The status per test and per subsystem: mechanism and timing, control circuit and coils, wear and contacts, dielectric and interrupting medium.
- The likely cause and the action for each finding, based on manufacturers’ technical documentation and the circuit-breaker diagnostics literature.
- The health index per parameter and composite (CHI), where alert and failure limits are available, using the method of Dehghanian, Popovic and Kezunovic.
- The action plan: the actions grouped by priority (immediate, before returning to service and next maintenance), without repetition and with the tests that give rise to them.
The report can be printed or downloaded in PDF, DOCX (Word) or ODT (LibreOffice), in the language of this page or, optionally, in twenty-one other languages. The curves and the history can also be exported to Excel (.xlsx) and LibreOffice Calc (.ods) with their charts. The diagnosis can also be sent by email, with the .odt report and the .json test file attached.
Tests assessed
| Test | Compared against | Standards |
|---|---|---|
| Opening and closing times, simultaneity between poles | Manufacturer’s reference and tolerance or the circuit-breaker’s signature | IEC 62271-100:2021 · IEEE C37.10-2011 |
| Travel curve: speed, overtravel and rebound | Reference envelope | IEC 62271-100:2021 |
| Main circuit resistance | Manufacturer’s value and difference between poles | IEC 62271-1:2017 · ANSI C37.16 |
| Coils: current signature, minimum operating voltage | Control voltage range and reference signature | IEC 62271-1:2017 · ANSI C37.16 · ANSI C37.32 |
| SF6 gas: density, leakage trend, moisture and purity | Filling, alarm and minimum functional levels | IEC 62271-1:2017 · IEC 62271-203:2022 |
| O–C, C–O and O–C–O sequences: dead time and close-open time | Manufacturer’s reference and rated operating sequence | IEC 62271-100:2021 |
| Dynamic resistance (DRM) and arcing contact | Manufacturer’s minimum arcing-contact wipe and the circuit-breaker’s signature | Manufacturer |
| Electrical wear (Σ I²t) and accumulated operations | Manufacturer’s limit and mechanical endurance class M1 / M2 | IEC 62271-100:2021 · IEEE C37.10-2011 |
| Mechanism: spring charging, motor, pump or compressor | Charging time and current, and starts compared with the signature | Manufacturer |
| Pre-insertion resistors, grading capacitors, heaters, oil, compressed air and vacuum interrupters | Nameplate and manufacturer’s values | IEEE C37.10-2011 |
| Bushing thermography and interlocks | Difference between poles and functional test | IEEE C37.10-2011 |
| Insulation resistance, auxiliary contacts, earthing continuity, auxiliary-circuit dielectric test and visual inspection | Values from the standard, the manufacturer and good practice | IEC 62271-1:2017 · IEEE C37.10-2011 |
How the status is determined
Each parameter is compared with its compliance limit (the manufacturer’s tolerance or the value in the standard) and with an earlier alert limit. Outside the tolerance the circuit-breaker fails; between the alert limit and the tolerance it passes with remarks. The status of each subsystem is that of its worst test, and the verdict is that of the worst subsystem. If you save successive tests of the same circuit-breaker, the History tab calculates the trend of each parameter and the estimated time until it reaches its limits.
Your data
The tool runs on Amperis servers and does not store your tests. Data is only saved or sent if you ask for it:
- Save test downloads a .json file to your computer.
- Your account history: the tests you save to your free account, protected by two-step verification, can only be seen by you. If you expressly allow it, when you sign up or later, Amperis can view them to provide technical support. You can withdraw that permission at any time and, if you delete a test or the account, it is no longer available to Amperis either.
- Email: the report is sent from diagnosticointerruptores@amperis.com with a copy to Amperis, and the form tells you about that copy.
- API for AI agents: it processes the measurements and files and discards them; it only counts the calls made with each key.
Access for AI agents: REST API and MCP
To integrate the diagnosis into your own systems or into an AI assistant, the tool provides a REST API and an MCP server with the same engine as this page: diagnosis from the measurements and analysis of analyser records (CSV, Excel, Calc and COMTRADE), with the result in any of the twenty-two report languages. API keys are created with the tool’s free account (password and two-step verification code), up to five per account and with a limit of 300 calls per key per day.
- API manual (also in Spanish): keys, calls, fields, examples and MCP server setup.
- OpenAPI specification and llms.txt for agents.
API results carry the same safeguard as the report: they are generated automatically, the software may contain errors and the tests must be reviewed with the circuit-breaker manufacturer.
What this tool does not do
- It does not replace the manufacturer. The values, tolerances and curves in the circuit-breaker manual always take precedence.
- It does not measure. It assesses the measurements you take with your own test equipment; the quality of the diagnosis depends on the quality of the measurements.
- It does not decide on energisation. It supports the responsible engineer, who is the one who validates the result.
Further information and equipment
The measurements the tool asks for are taken with circuit-breaker analysers such as the CAT Advanced Series, with micro-ohmmeters such as the RMO-A for contact resistance, with coil analysers and, for SF6, with gas analysers and leak detectors. The full range is listed under Circuit-breaker testing. For gas mass and moisture, use the SF6 calculator and, to correct insulation readings for temperature, the insulation resistance calculator.
Indicative result. The calculation runs in your browser and is not sent to any server. This website may contain errors or omissions: before making any decision about an installation, the information must be checked and validated by a qualified engineer. The battery and circuit breaker diagnostic tools run on Amperis servers; calculations are not stored unless you expressly choose to do so. Legal notice and terms of use
Frequently asked questions
- What measurements do I need to use the tool?
- Whatever you have. The nameplate data (rated voltage and current, frequency and control voltage) and one test are enough, for example the opening and closing times or the contact resistance of each pole. Each test is assessed separately, and those that are missing are shown as pending, together with the standard that requires them. The more tests you enter, the more complete the subsystem diagnosis and the health index.
- Which criteria does it apply: IEC or IEEE?
- Those of the IEC 62271 series (62271-1, -100, -110 and -203) or those of ANSI / IEEE C37 (IEEE C37.04-2018 and C37.10, ANSI C37.16 and C37.32), selected on the equipment sheet. Where the standard refers to the manufacturer, as for timing or contact resistance, the tool uses the reference and tolerance you enter or, failing that, the circuit-breaker’s own signature from a previous test.
- Can I import the curves from my circuit-breaker analyser?
- Yes. The Record tab reads COMTRADE files (.cfg/.dat or .cff), CSV or TXT, and .xlsx, .xls and .ods spreadsheets containing the travel, coil current, main and auxiliary contact, control voltage and dynamic resistance curves. You assign the use of each channel and the tool extracts the times, speeds, overtravel, rebound and the coil signature.
- Is my test data stored?
- No, unless you ask for it. The tool runs on Amperis servers but does not store the calculations. You can save each test to a .json file on your computer or, if you open a free account with two-step verification, to the history on the Amperis server, to track how the circuit-breaker evolves. Only you can see that history unless you expressly allow Amperis to view it for technical support; you can withdraw that permission at any time.
- Can I compare several tests of the same circuit-breaker?
- Yes. In the History tab you can view the tests saved to your account or add the .json files of earlier tests of the same circuit-breaker (same manufacturer and serial number). With two or more, the report includes a test-by-test comparison, the annual trend of each parameter with its chart and the estimated time until its alert and failure limits are reached.
- Can it be used from an AI agent or from our own systems?
- Yes. The tool has a REST API and an MCP server for AI agents such as Claude or Cursor, with the same diagnostic engine as this page. Keys are created with the tool’s free account, and the API does not store measurements or files: it processes them and discards them. The manual, in English and Spanish, explains the calls, the fields and how to connect the MCP server.