Regarding inverter knowledge, before installing an inverter, the installation environment must be determined, and then a suitable installation method should be used. When wiring the inverter, the main circuit and control circuit must be correctly wired. Let's take a look at the details below.

I. Inverter Installation Requirements

1. Inverter Installation Environment

(1) Ambient Temperature: -10℃～40℃;

(2) Ambient Humidity: Relative humidity not exceeding 90% (no condensation);

(3) Other Conditions: No direct sunlight, no corrosive gases or flammable gases, low dust, altitude below 1000m. 

2. Inverter Installation Methods 

(1) Wall-mounted installation: The distance between the inverter and surrounding objects should meet the following conditions: ≥100mm on both sides and ≥150mm vertically; 

(2) Cabinet installation: For single inverter installation, external cooling should be used as much as possible (when the environment is relatively clean and dust-free); when using internal cooling for a single inverter, an exhaust cooling fan should be installed on the top of the cabinet, preferably directly above the inverter; multiple inverters should be installed side-by-side as much as possible. If vertical installation is necessary, a partition should be installed between the two inverters. Regardless of the method, the inverter should be installed vertically. 

II. Wiring of the Inverter

1. Wiring of the Main Circuit

(1) The inverter input (R, S, T) and output (U, V, W) must not be connected incorrectly; 

(2) Selection of wire diameter for the main circuit 

① The wiring method between the power supply and the inverter is the same as that for motors of the same capacity;

② The wiring between the inverter and the motor should take into account the line voltage drop △U. Generally, it is required that: △U≤(2～3)%Un The formula for calculating △U is: (not copied here) Where: Imn－Motor rated current (A) R0－Resistance of conductor per unit length (mΩ/m), which can be found in the following table:

L－Length of conductor (m) Nominal cross-sectional area / 1.0 1.5 2.5 4.0 6.0 10.0 16.0 25.0 35.0 /（mΩ/m）17.8 11.9 6.92 4.40 2.92 1.73 1.10 0.69 0.49

Table: Resistance per unit length of motor lead wire

2. Wiring of control circuit 

(1) Shielded wires should be used for analog control lines. One end of the shield should be connected to the common terminal (COM) of the inverter control circuit, and not to the inverter ground terminal (E) or earth. The other end should be left floating. 

(2) Shielded wires are allowed for switch control lines, but the two wires of the same signal must be twisted together.

3. Grounding of inverters When multiple inverters are grounded, each inverter should be connected to earth separately. It is not allowed to connect the grounding of one inverter to the grounding terminal of another inverter and then ground it. To improve the power factor of the inverter, add DC reactors and AC reactors. In addition to improving the power factor, it can also play the following roles:

(1) Suppressing surge current in the input; 

(2) Weakening the effects of power supply voltage imbalance. Reactor selection: 

1) The voltage drop of the reactor should not exceed 3% of the rated voltage;

2) When the transformer capacity is greater than 500KVA or the transformer capacity exceeds 10 times the inverter capacity, a reactor should be used.