Standard compatibility

When selecting equipment, it is necessary to confirm that it complies with core international standards, such as:

IEC 60112: Methods for determining the electrical trace resistance index and comparative electrical trace resistance index of solid insulation materials;

GB/T 4207-2022: Chinese National Standard, specifies the determination of the electrical trace index under humid conditions;

UL 746A, ASTM D3638: Commonly used standards in North America, involving the evaluation of material resistance to electrical traces.

Core performance parameters

Voltage range: 100V-600V, covering low to high voltage testing requirements;

Current stability: The short-circuit current needs to be precisely controlled at 1.00N ± 0.001N to avoid result deviation caused by current fluctuations;

Dropping accuracy: using micro pump technology to ensure a single droplet volume of 0.380g-0.480g or 0.997g-1.147g, with an error of ≤± 5%;

Electrode size and spacing: The platinum electrode size is (2mm ± 0.1mm) × (5mm ± 0.1mm) × (40mm ± 5mm), with a fixed spacing of 4.0mm ± 0.01mm and an angle of 60 °± 5 °.

Automation and Security

Automation function: Choose equipment that supports automatic recording of droplet count, current/voltage curve, and test results to reduce human error;

Safety protection: equipped with splash guard, emergency stop button, high-voltage danger sign, and supports overcurrent protection.

2、 Operation process: Standardized steps ensure repeatable results

Pre-test preparation

Environmental control: temperature 23 ℃± 2 ℃, humidity ≤ 80%, no flammable or explosive materials, good ventilation;

Sample processing:

Size: The sample of the flat inclined surface should be at least 50mm × 120mm, with a thickness of 6mm;

Cleaning: Clean with isopropanol and rinse with distilled water to remove oil stains and impurities;

Polishing: If the surface of the sample is not moist, use 400 grit diamond sandpaper and deionized water to polish it evenly until it is dull, then clean and dry it again.

Equipment Calibration

High voltage power calibration: Compare with a standard high voltage power supply and adjust the output value error of the equipment to ≤± 1%;

Electrode calibration: Verify the shape, size, and spacing with standard electrodes to ensure compliance with IEC 60112 requirements;

Leakage current calibration: By using standard resistors and ammeters, the measurement range error is controlled within ≤± 2%.

Experimental parameter setting

Voltage selection: Set the test voltage according to the standard, for example, CTI testing usually starts from 250V and gradually increases by 250V;

Droplet control:

Droplet height: 35mm ± 5mm;

Dropping time: 30s ± 0.1s;

Test solution resistance: A solution has a resistance of 3.95 Ω m ± 0.05 Ω m, while B solution has a resistance of 1.98 Ω m ± 0.05 Ω m.

Experimental execution and monitoring

Start test: Press the "Start" button, and the equipment will automatically drip and apply voltage according to the set parameters;

Real time observation: Monitor current changes. If the current is greater than 0.5A for 2 seconds, the equipment will automatically power off and mark "unqualified";

Exception handling: If the sample catches fire, immediately press the "stop" button or cut off the power.

Post experimental processing

Data recording: Save voltage, current, number of drops, and test results;

Equipment cleaning: Use neutralizing agents to treat residual electrolytes, and collect waste liquids according to hazardous chemical regulations;

Sample analysis: Measure the depth of corrosion and record the maximum value.

3、 Key considerations: Avoid risks and improve the reliability of results

safety protection

Operators are required to wear insulated gloves, goggles, corrosion-resistant lab coats, and insulated shoes;

Do not touch electrodes, samples, or electrolytes with bare hands, and maintain a safe distance of at least 30cm under high voltage.

Equipment maintenance

Daily cleaning: Clean the drip needle daily, check electrode wear weekly, and test insulation performance monthly;

Regular calibration: Conduct grounding resistance testing every quarter and annual withstand voltage testing;

Fault handling: Unauthorized personnel are not allowed to repair, and faulty equipment must be marked with a "no operation" sign and handled by a certified engineer from the manufacturer.

personnel training

Operators need to receive professional training, be familiar with equipment manuals, emergency procedures, and material safety data sheets;

Annual refresher training, updating emergency knowledge, and signing safety responsibility agreements.