Basic wiring method of inverter

The basic wiring diagram of the inverter is shown in Figure 10-7.

Figure 10-7 Basic wiring diagram of the inverter

Pay attention to the following points when wiring.

(1) The input power must be connected to terminals R, S, and T, and the output power must be connected to terminals U, V, and W. If the connection is incorrect, the inverter will be damaged.

(2) To prevent accidents such as electric shock and fire and to reduce noise, the ground terminal must be connected.

(3) The connection between the terminal and the wire should be firm, and crimping terminals with good contact should be used.

(4) After wiring, check again to see if the wiring is correct, whether there is any missing connection, and whether there is a short circuit or grounding between the terminal and the wire.

(5) After power is on, if you need to change the wiring, even if the power is turned off, it will take time for the filter capacitor at the DC terminal of the main circuit to discharge, so it is very dangerous. Wait until the charging indicator light goes out and use a multimeter to confirm that the DC voltage between the P and N terminals has dropped to a safe voltage (below DC 36V) before operating.

Wiring of main circuit terminals

The main circuit wiring diagram of the inverter is shown in Figure 10-8.

Figure 10-8 Main circuit wiring diagram of the inverter

The functions of the main circuit terminals are shown in Table 10-7.

Table 10-7 Main circuit terminal function description

The following points should be noted when wiring the main circuit.

(1) The main circuit terminals R, S, and T are connected to the power supply through contactors and circuit breakers without considering the phase sequence.

(2) The inverter should not be operated by turning the main circuit on and off. Instead, the operation should be performed using the RUN and STOP keys on the control panel.

(3) It is best to connect the inverter output terminals to the three-phase motor through a thermal relay. When the rotation direction is inconsistent with the setting, any two phases of U, V, and W should be swapped.

(4) The neutral point of a star-connected motor must never be grounded.

(5) For the sake of safety and noise reduction, the inverter must be grounded. The grounding resistance should be less than or equal to the value specified in the national standard, and a thick short wire should be connected to the dedicated grounding terminal of the inverter. When several inverters are grounded together, do not form a grounding loop, see Figure 10-9.

Figure 10-9 The grounding wire must not form a loop

Wiring of control circuit terminals

The arrangement of the control circuit terminals is shown in Figure 10-10.

Figure 10-10 Arrangement of inverter control circuit terminals

The symbols, names and functional descriptions of the control circuit terminals are shown in Table 10-8.

Table 10-8

Table 10-8 Symbols, names and functional descriptions of control circuit terminals

Continued

(1) The control circuit wiring must be separated and kept away from the main circuit control line or other high-voltage (or high-current) power lines to avoid interference.

(2) The control circuit wiring terminals F1, F2, FA, FB, and FC (contact output) must be wired separately from other terminals.

(3) To prevent interference and malfunction, shielded isolated twisted wires must be used for control circuit wiring, see Figure 10-11. When using, connect the shielded wire to terminal G, and the wiring distance should not exceed 50m.

Figure 10-11 Shielded isolated twisted wire for wiring