Daikin FTKD50BVM, Service Manual

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Main Functions Si04-306
34 Function and Control
1. Main Functions
Note: See the list of functions for the functions applicable to different models.
1.1 Frequency Principle
Main Control
Parameters The compressor is frequency-controlled during normal operation. The target frequency is set by
the following 2 parameters coming from the operating indoor unit:
„
The load condition of the operating indoor unit
„
The difference between the room temperature and the set temperature
Additional
Control
Parameters The target frequency is adapted by additional parameters in the following cases:
„
Frequency restrictions
„
Initial settings
„
Forced cooling operation
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:
Phase Description
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.
50 Hz
60 Hz
Refrigerant circulation rate (high)
Amount of heat
exchanged air (large)
Amount of heat
exchanged air (small)
AC
po
w
e
r
freq=
constant
DC
po
w
e
r
Amount of heat
exchanged air (large)
Amount of heat
exchanged air (small)
high f
low f
freq=variable
capacity=
variable
Refrigerant circulation rate (low)
high speed
low speed
(R2812)