The first power-on after magnesium oxide refilling must ensure that the components are completely cooled, pass the cold-state test, and meet insulation standards to avoid breakdown, short circuit, or equipment damage.
Key Precautions for the First Power-On
Confirming Completion of Cooling
The components must be allowed to cool naturally to room temperature (approximately 25°C) after sintering. Forced air cooling or water cooling is strictly prohibited. After removal from the furnace, allow the components to stand for 30–60 minutes to ensure no residual heat causes thermal stress cracking.
Passing the Cold-State Performance Test
Insulation resistance ≥500 MΩ (500V DC);
Withstand voltage test passed: AC 2000V, no breakdown or flashover within 1 minute;
The test should use calibrated instruments to eliminate surface leakage interference.
Low-Power Preheating Start-up
Apply 50% of the rated voltage for initial power-on and run for 10–15 minutes; Observe whether the temperature rise is stable, the current does not change abruptly, and there are no abnormal noises or smoke.
Gradually increase to full load.
After confirming normal low-power operation, gradually increase to 100% power; continue operation for 30 minutes to prepare for subsequent hot-state testing.
Real-time monitoring and safety protection.
Integrate a leakage current protection device and set an overcurrent alarm;
If equipped with an online monitoring system, record the trend of insulation resistance changes to promptly detect latent defects.
Powering on without sufficient cooling or without passing the cold-state test may lead to insulation breakdown, casing rupture, or even fire, and must be strictly prohibited.
