The most critical indicator in hot-state testing is the insulation resistance value within 2 seconds after power failure, with a standard of ≥200 MΩ. This indicator directly reflects the stability and integrity of the magnesium oxide insulation layer at high temperatures.
Detailed Explanation of Core Indicators in Hot-State Testing
|
Indicator |
Key Standard |
Function and Significance |
|
Hot-state Insulation Resistance |
≥200 MΩ (500V DC, measured within 2 seconds after power failure) |
Verifies the stability of the insulation structure under high-temperature conditions, preventing leakage or breakdown. |
|
Power Failure Response Time |
Measurement completed within 2 seconds |
Ensures the temperature has not dropped, and the data accurately reflects the insulation performance under operating conditions. |
|
Operating Temperature Rise Curve |
Stable temperature rise without fluctuations |
Determines whether the filling density is uniform and whether there is a risk of localized overheating. |
|
Current Stability |
No sudden changes in current at rated power |
Investigates potential problems such as poor lead contact or internal short circuits. |
Hot-state insulation resistance is the core of the core. If it is below 200 MΩ, it indicates incomplete sintering or sealing failure, leading to moisture intrusion and a risk of high-temperature conductivity.
Test Condition Guarantee Indicators:
Ambient Humidity: ≤30% to prevent surface leakage from interfering with readings;
Cold State Test Pass: Must first pass insulation resistance (≥500 MΩ) and withstand voltage tests (AC 2000V, 1 minute without breakdown);
Power-On Duration: Continuous operation for 30 minutes to ensure the component reaches thermal equilibrium.
Testing without meeting the above conditions may lead to data distortion and mask potential defects.
