Maintenance Guides 1 min read

Circuit Breaker Maintenance and Service: Arc Breaker Inspection, Contact Resistance Measurement, and Circuit Breaker Testing

Technical analysis: Switchgear maintenance: arc chute inspection, contact resistance measurement, and trip unit testing

Підтримка та обслуговування вимикача: перевірка дугового вибивача, вимірювання опору контактів та тестування вимикача - UNITEC-D Industrial MRO
Це практичне посібник для обслуговування вимикачів, охоплює перевірку дугового вибивача, вимірювання опору контактів та тестування вимикача. Включено детальну процедуру, табличні дані, перевірки та ре

1. Purpose and scope

This technical manual is intended for the maintenance of circuit breakers of complex design used in industrial installations. It covers arcing breaker testing, contact resistance measurement, and circuit breaker testing. It is recommended that these procedures be performed regularly, especially after failure or during routine maintenance.

2. Safety during maintenance

Important: Before starting any work, turn off the power supply and install the tag lock. Use personal protective equipment (PPE), including work gloves, goggles, and safety helmets. When working with high voltage, use tools with insulation and take additional protective measures.

3. Necessary tools and materials

Tool/material Specification Quantity
Torque rifle 10–100 N·m 1
Multimeter Range: 0-1000 Ω, 0-1000 V, 0-10 A 1
Laser for measuring aluminum Power: 5 mW, accuracy: ±0.01 mm 1
A separate cleaning tool Under the tripod 1
Support washers Material: stainless steel 2

4. Inspection before service

Item Verification Acceptance/rejection criteria Notes
Electricity supply Disabled Lack of tension Use a multimeter to check.
Tag lock Installed Tag lock is installed Use tools with insulation.
Clothes Full PPE in full Surface protection is not allowed.
Ambient temperature Measured in advance Between 10–40 °C Measure with a thermometer.

5. Passport service procedure

  1. Measurement of contact resistance

    1. Use a multimeter to measure the resistance between the pins. Set the resistance mode (Ω).
    2. Measure the resistance between the contacts on the switch. The resistance should be less than 100 mΩ.
    3. If the resistance is higher than 100 mΩ, clean the contacts or replace them.
    4. Error: The wrong mode on the multimeter can lead to incorrect readings.

  2. Arc Puncher Test

    1. Clean the arc puncher of abrasive substances and dust. Use a cleaning tool.
    2. Check the distance between the contacts. The distance should be 1–2 mm.
    3. Use the laser to measure the distance. Write down the readings.
    4. Error: Incorrect distance measurement can lead to unstable switch operation.

  3. Switch testing

    1. Set the switch to the off position and check if it complies with EN 60947-2. standards
    2. Apply the device to test the circuit breaker. Measure current and voltage. The current should be in the range of 10–100 A.
    3. Check that the circuit breaker meets the requirements of DSTU 3331:2006.
    4. Error: An error in device settings may result in incorrect testing.

  4. Restoring contacts

    1. Use the contact recovery tool and restore their shape.
    2. Install new thrust washers and grease.
    3. Check the distance between the contacts. The distance should be 1–2 mm.
    4. Error: Improper installation of washers can cause wear.

  5. Returning the switch to working condition

    1. Set the switch to the operating position.
    2. Check all connections and compliance ISO 12100.
    3. Perform a stability test.
    4. Error: Lack of testing can lead to unexpected failures.

6. After-service inspection

Test Expected result Actual result Pass/Fail
Contact resistance Less than 100 mΩ The resistance is measured Pas
Distance between contacts 1–2 mm The distance is measured Pas
Circuit breaker testing Current 10–100 A The current is measured Pas
Compliance with standards EN 60947-2, DSTU 3331:2006 Standards are verified Pas

7. Issue tracking

Symptom A possible reason Correction
The switch does not work Complete rejection of contacts Clean the contacts or replace them
The switch does not turn off The arc breaker does not work at all Check the distance and resume
The switch fails Incorrect installation of washers Install the washers correctly
Measurement readings deviate Incorrect device settings Check your device settings

8. Recommended maintenance schedule

Task Frequency Estimated duration Skill level
Measurement of contact resistance Annually 1–2 hours Average
Checking the arc puncher Annually 1–2 hours Average
Circuit breaker testing Annually 1–2 hours Average
Restoring contacts Annually 1–2 hours Average

9. Links to spare parts

Part description Typical specification UNITEC-D category
Contacts Material: stainless steel, resistance: 100 mΩ Category 12
Support washers Material: stainless steel Category 13
Laser for measurement Power: 5 mW, accuracy: ±0.01 mm Category 14

For spare parts, visit our catalog: https://www.unitecd.com/e-catalog/

10. Links

- EN 60947-2: Measurement of circuit-breakers - DSTU 3331:2006: General requirements for circuit-breakers - ISO 12100: Safety in industrial systems - OEM documentation: Additional requirements of the manufacturer

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