1. Disconnect the power supply of the variable frequency control cabinet, check whether the rack is firmly grounded, and make the grounding resistance not greater than 4 Ω.

2. 
   

2. There are different kinds of voltages on the frequency conversion control cabinet (DC 110V; communication single-phase 220V; three-phase communication), so the circuit must be distinguished during maintenance to prevent short circuit accidents.

3. All electrical switches on the frequency conversion control cabinet shall operate flexibly and reliably without significant noise, the connection wire terminals and terminals shall be free of looseness, and the steel wire at the connection wire terminals of moving contacts shall be free of cracking.

4. Use a soft brush or blower to clear the dust on the panel plug-in and all electromagnetic switch parts, and check the status of the electrical switch contacts in the variable frequency control cabinet, the touch status, the insulation of the coil surface, and whether the action of the mechanical components is secure.

5. When replacing the fuse of the frequency conversion control cabinet, the fusing current should match the current of the circuit.