We know that during normal operation, the explosion-proof pressurized cabinet maintains a certain internal pressure, typically around 100 pascals, and is absolutely sealed from the external atmosphere. During normal operation or under full load, electrical equipment generates heat. Aging equipment and poor contacts can also cause electrical heating, while high external temperatures can lead to cabinet overheating.

The consequences are: excessive heat can cause electrical aging, reduce lifespan, and burn out electrical components.

Therefore, explosion-proof pressurized cabinets generally have strict requirements for their storage location and must be used in conjunction with explosion-proof air conditioners. This ensures a normal temperature working environment inside, allowing the equipment to operate optimally.

1. When the air pressure exceeds 1000 Pa, the pressure relief valve automatically opens the exhaust valve to adjust the internal pressure, ensuring the product is not deformed or damaged by high-pressure impact.

2. When the air pressure falls below 50 Pa, the automatic control system issues an alarm and outputs an alarm signal. The internal pressure needs to be adjusted. If pressure replenishment is successful, the system automatically returns to normal. Otherwise, the system can be set to automatically cut off power if necessary (national standards require cutting off power for low-pressure alarms in Zone 1, while low-pressure alarms in Zone 2 do not require power cutoff).

3. Only when the cabinet pressure meets the specified requirements will the pressurized purging control system perform effective air exchange (Zone 1 requires 7 times the free space volume, Zone 2 requires 5 times). After effective air exchange is completed, a signal is provided to power the cabinet.

4. The working pressure inside the pressurized cabinet is 50 Pa ≤ P ≤ 1000 Pa.

Under the control of the automatic system, protective gas is introduced, creating a slightly pressurized safe environment inside the pressurized chamber where pressure is higher than outside. This prevents combustible hazardous gases from entering the pressurized chamber, ensuring the safe operation of ordinary instruments and electrical components inside. The automatic control system primarily performs functions such as manual air exchange, pressure replenishment, high-pressure automatic alarm and exhaust, low-pressure alarm, and low-pressure interlock power cutoff. (This distribution cabinet has a low-pressure interlock function: when pressure falls below the specified value (50 Pa), it automatically cuts off the user's power supply to the pressurized chamber.)