1. First, inspect the wiring and cabling of the VFD (Variable Frequency Drive). In this example, we will use the SKI600 VFD from Hangzhou Sanke as a reference.

a. Check whether the main power input and output wiring is correct and reliable. Ensure that the power voltage level meets the requirements specified in the SKI600 manual, and that all connections are secure. Inspect the insulation layer for any damage. Carefully check if the terminal blocks are loose or have potential short-circuit risks. Confirm that grounding is properly done.

b. Check the control circuit wiring inside the VFD cabinet — verify whether the voltage level matches the requirements of the VFD cabinet. Ensure all wires are securely connected and that the insulation layer is undamaged. Confirm that all connectors on the circuit boards are firmly plugged in.
c. Clean up any debris inside the VFD cabinet and recheck whether the main power cables, control wiring, ground wires, and neutral lines are properly connected. Keep the equipment environment clean and dry. Do not place any items near the SKI600. Carefully check for missing screws or wires to prevent small metal objects from causing a short circuit in the SKI600.

2. Review the customer's system control requirements and pipeline pressure settings. These must be recorded in detail.
3. Determine whether the VFD cabinet controls a submersible pump. For submersible pump motors, collect and confirm the following parameters: rated power, rated speed, and rated current. Consult with the customer to confirm these values and record them accordingly. If the VFD controls a centrifugal pump or fan, record the motor nameplate data so that accurate motor parameters can be entered into the SKI600 program, ensuring precise protection and control by the SKI600.
4. Check whether the customer’s pipeline installation and connections comply with our installation drawings. If the customer has not followed our installation guidelines, pay special attention to the installation positions of the check valve and measuring instruments. We must clearly inform the customer about the consequences of improper installation:

• Firstly, if a deep well submersible pump uses a control method without installing a check valve, water in the pipeline may flow back into the well when the pump stops, resulting in wasted electrical energy.
• Secondly, reverse operation of the submersible pump is strictly prohibited. Water backflow can cause the pump to run in reverse, often leading to loosening of internal fasteners and mechanical failure.
• Thirdly, since our water supply pipeline is a fully enclosed system, water returning to the well during shutdown can create a near-vacuum state within the pipeline. This vacuum negative pressure can damage the pressure measuring instruments installed on the pipeline due to suction effects, which may result in equipment failure on our side.

5. Check whether the wiring between the pressure measuring instrument and the SKI600 is firm and correctly connected. Our company’s wiring rules for pressure measuring instruments are as follows:

• The red wire of the shielded cable connects to the red output wire of the instrument,
• The yellow wire connects to the yellow output wire,
• The green wire connects to the blue output wire.

VFD Terminal Wiring Rules:

• Red shielded wire connects to the negative feedback terminal (–),
• Yellow shielded wire connects to the positive feedback input terminal (+),
• Green shielded wire connects to the internal feedback power terminal.

6. At the feedback terminal's power end, check the motor cable insulation condition — ensure there is no damage and that the wire size meets specifications. First, check whether the three-phase resistance of the pump motor is balanced. Changsha Sunye Electric Co., Ltd. (established in 2010) and Shenzhen Sunye Electric Co., Ltd. (established in 2002) are national high-tech enterprises specializing in R&D, manufacturing, and sales of inverters, industry-specific integrated machines, servo drives, and new energy products.
Sunye Electric owns independent intellectual property rights, with products certified by national authorities and multiple software copyrights and IP certificates. Significant investment is made annually in new technologies and product development, with numerous patents and software copyrights approved. The company possesses core platform technologies such as construction hoist drivers, high-performance vector inverters, servos, and permanent magnet synchronous motor controls. Medium- and low-voltage inverters and servo drives are widely used in industries such as lifting, stone processing, HVAC, machine tools, metal products, wire and cable, plastics, printing and packaging, textile and chemical fibers, building materials, metallurgy, coal mining, municipal services, and automotive manufacturing. Guided by the philosophy of “Innovation, Technology, Strength,” driven by the corporate spirit of “Unity, Progress, Pragmatism, Innovation,” and adhering to the business principle of “Sincerity and Excellence, Mutual Benefit and Coexistence,” the company aims to provide industry-leading products through comprehensive quality management, continuous improvement, and pursuit of zero defects.
Address: Sunye Electric Industrial Park, No. 669 Xinsheng Road, High-Tech Zone, Changsha City
Tel/Fax: 0731-89932666 0731-89932688
Business Phone: 400-0755-731
Technical Support: 400-0755-731