SiUS04-924_A Main Functions
14 Function and Control
Inverter Principle To regulate the capacity, a frequency control is needed. The inverter makes it possible to vary the
rotation speed of the compressor. The following table explains the conversion principle:
Drawing of
Inverter
The following drawing shows a schematic view of the inverter principle:
Inverter Features The inverter provides the following features:
The regulating capacity can be changed according to the changes in the outdoor temperature
and cooling / heating load.
Quick heating and quick cooling
The compressor rotational speed is increased when starting the heating (or cooling). This
enables to reach the set temperature quickly.
Even during extremely cold weather, high capacity is achieved. It is maintained even when the
outdoor temperature is 2°C (35.6°F).
Comfortable air conditioning
A fine adjustment is integrated to keep the room temperature constant.
Energy saving heating and cooling
Once the set temperature is reached, the energy saving operation maintains the room
temperature at low power.
Phase Description
1 The supplied AC power source is converted into a DC power source.
2 The DC power source is reconverted into a three-phase AC power source with variable
frequency.
When the frequency increases, the rotation speed of the compressor increases resulting in
increased refrigerant circulation. This leads to a higher amount of heat exchange per unit.
When the frequency decreases, the rotation speed of the compressor decreases resulting
in decreased refrigerant circulation. This leads to a lower amount of heat exchange per unit.
Refrigerant circulation rate (high)
high f
low f
freq=variable
Refrigerant circulation rate (low)
high speed
low speed
(R2812)
Amount of heat
exchanged air (large)
freq=
constant
50 Hz
60 Hz
capacity=
variable
Amount of heat
exchanged air (small)
AC
power
DC
power
Amount of heat
exchanged air (large)
Amount of heat
exchanged air (small)