How to Use Single phase Compressors with 3 Phase power input(220V) or vice versa

*Single phase U.S. Air Compressors can work for single phase or 3 phase voltage as they are all driven by an intelligent VSD/VFD.

The way to connect single phase U.S. Air Compressor models is simple and easy. There is no extra programming or software change is required.

There are total three types of compressors can be connected as single phase. Choose appropriate type of wiring configuration according to electrical configuration of the compressor.

Type:1 Compressors with separate power input terminal box

On the main input terminal block, there are three input terminals. The left (Terminal#1) and the right one (Terminal#2) are designated as L1 and L2 for single phase use. Those lines must be connected for single phase only. If there is the 3rd phase available, 3rd phase must be connected to the middle input terminal (Terminal#3).

Terminal 3 location on main power input terminal box;

There is no connection in between Terminal#3 and VSD/VFD in order to make sure the first and last terminals are used only, when compressor is to be connected as single phase. It is needed to connect the Terminal#3 to VSD/VFD with the same size of a cable used for L1 and L2 to connect from the input terminal. The VSD/VFD input terminal from Terminal#3 is the VSD/VFD terminal placed in between L1 and L2 inputs of VSD/VFD, similar to Main power input terminal.

VSD/VFD 3rd phase input terminal;

Type: 2 Compressors with single inverter and no separate terminal box

Type:3 Compressors with single inverter and no separate terminal box

In order to use type 3 wiring configuration, Terminal #1 ( R ) and Terminal #2 ( S ) needs to be connected using jumper cable and Terminal #3 ( T ) must be connected separately.