Main Functions; Frequency Principle - Daikin CTXU25G2V1B Service Manual

SiBE12-908

1. Main Functions

1.1

Frequency Principle

Main Control The compressor is frequency-controlled during normal operation. The target frequency is set by
the following 2 parameters coming from the operating indoor unit:
Parameters
Additional The target frequency is adapted by additional parameters in the following cases:
Control
Parameters
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 The following drawing shows a schematic view of the inverter principle:
Inverter
Function and Control
The load condition of the operating indoor unit
The difference between the room temperature and the set temperature
Frequency restrictions
Initial settings
Forced cooling operation
Phase
1 The supplied AC power source is converted into the DC power source for the present.
2 The DC power source is reconverted into the three phase AC power source with variable
frequency.
When the frequency increases, the rotation speed of the compressor increases resulting
in an increased refrigerant circulation. This leads to a higher amount of the heat
exchange per unit.
When the frequency decreases, the rotation speed of the compressor decreases
resulting in a decreased refrigerant circulation. This leads to a lower amount of the heat
exchange per unit.
Amount of heat
exchanged air (large)
Amount of heat
exchanged air (small)
Description
Refrigerant circulation rate (high)
high f
low f
50 Hz
freq=
freq=variable
60 Hz
constant
Refrigerant circulation rate (low)
high speed
Amount of heat
exchanged air (large)
Amount of heat
exchanged air (small)
low speed
capacity=
variable

Main Functions

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