The first power-on after magnesium oxide refilling typically requires a wait of 3–5 hours. This is the time needed to complete sintering, cooling, and necessary testing. The specific duration depends on the rigor of the process execution.
Key Time Nodes Before First Power-On
Stage Time Description
Sintering Holding 1–2 hours Ensures sufficient recrystallization of magnesium oxide grains at 800–1000℃
Natural Cooling in Furnace 1–2 hours Cools with the furnace to <200℃ to prevent thermal stress cracking
Cooling to Room Temperature After Removal from Furnace 30–60 minutes Ensures the component temperature stabilizes at around 25℃ to avoid testing errors
Cold Performance Testing ≤30 minutes Must pass insulation resistance (≥500 MΩ) and withstand voltage tests (AC 2000V, no breakdown in 1 minute) The first power-on can be performed as early as 3 hours after sintering begins, provided that all cooling and testing steps have been completed and the results are satisfactory.
Conditions to be met before energizing:
Normal physical condition: The casing is free from deformation, cracks, or bulges, and the seal is tight.
Electrical performance meets standards: Cold-state insulation resistance and withstand voltage tests are all qualified.
Dry environment: The humidity of the testing and energizing environment is ≤30% to prevent surface leakage.
Safety protection in place: The power supply circuit is equipped with leakage protection and overcurrent alarm devices.
Engaging in the circuit without sufficient cooling or without passing tests may lead to insulation breakdown, casing rupture, or even fire, and must be strictly prohibited.
