1、Safety Instructions

(1)Only qualified personnel are authorized to operate, inspect, or maintain the electrical cabinet. Unauthorized personnel are strictly prohibited.

(2)After power disconnection, the cabinet must be verified de-energized, locked out, and tagged out before any work begins. This prevents accidental re-energization.

(3)After the equipment is powered off, wait until all indicator lights and display screens on electrical components have completely turned off before performing any operations. This eliminates the risk of electric shock from residual voltage.

(4)Energized work is not permitted unless absolutely necessary. When energized work must be performed, a dedicated supervisor must be present at all times.

2、Major Risks of High Temperature on Electrical Control Cabinets

Rotomolding machines operate in environments with both oven radiant heat and high summer ambient temperatures. The electrical control cabinet faces the following key risks during summer operation:

3、Daily Operating Precautions

（1）Running Checks (Each Shift)

•Monitor cabinet temperature: Cabinet temperature shall not exceed 45°C; cabinets equipped with VFDs or PLCs are recommended to be kept below 40°C.

•Verify that cooling fans and cabinet-top exhaust fans are running normally with no abnormal noise.

•Inspect cabinet door sealing strips for integrity; confirm doors are closed and locked.

•Ensure a minimum clearance of 800 mm is maintained at the front and rear of the cabinet for ventilation; no materials shall be stored nearby.

•After heavy rainfall, open the cabinet door to check for water ingress or condensation marks.

（2）Key Component Inspection

（3）During Shutdown

•For extended shutdowns exceeding 2 hours, disconnect the main power supply.

•During thunderstorms, disconnect the main power supply to prevent lightning surge from entering through power lines and damaging sensitive equipment such as PLCs and VFDs.

•Clean the exterior of the cabinet body to keep ventilation openings unobstructed.

4、Summer-Specific Maintenance (Recommended Weekly)

（1）Filter Cleaning

Filter cotton at the cabinet air intake is used to block external dust from entering. Maintenance frequency should be increased during summer.

•Remove the filter cotton and use compressed air to blow out accumulated dust from inside to outside. Filter cotton must be completely dry before reinstallation after water washing.

•For heavy dust or oil contamination, soak and clean with a neutral detergent, then dry thoroughly before reinstalling.

•Replace the filter immediately if damage or deformation is found.

（2）Cooling Fan

•After power disconnection, manually rotate the fan blades to check for smooth rotation and any jamming.

•Use dry compressed air to remove dust from fan blades and air ducts.

（3）Electrical Connection Tightening (Must Be Done When Powered Off)

Summer temperature fluctuations cause frequent thermal expansion and contraction, making electrical joints prone to loosening.

（4）Insulation Testing

•Use a 500V megohmmeter to measure the main circuit insulation resistance to ground; it shall not be less than 1 MΩ.

•In humid environments, prioritize insulation testing of the main circuit to ground.

•If insulation resistance is found to be reduced, disconnect the power and use hot air or an anti-moisture heater for drying treatment.

（5）Temperature Monitoring

Use an infrared thermometer to scan key areas and establish summer temperature baseline data:

•Main circuit breaker terminals

•Contactor terminals and contact areas

•VFD heat sinks

•Heating circuit solid-state relays and contactors

If the temperature difference between phases at the same location exceeds 10°C, shut down the machine and investigate the cause.

5、Emergency Response

6、Recommended Summer Spare Parts List

Wenling Rising Sun Rotomolding Technology Co., Ltd.

www.risingsunroto.com