20 Room Air Conditioner
Part 2 Functions & Controls
5.6 Power Relay Control
• Power relay turns on 1 second later after the power is supplied to the outdoor unit.
• Control sequence : power on →PTC operating →power relay on
5.7 Inverter
1. The single phase power AC is converted into DC.
2. The single phase power DC is converted into a three phase chopped DC voltage with a variable frequency.
3. When the frequency changes, the rotation speed of the compressor changes resulting in an changed refrigerant circu-
lation. This leads to changeable amount of the heat exchange per unit.
3Ø
Comp.
Motor
U
UVW
V
W
+