Electrical data, connections and wiring
The compressor terminal box IP rating according to CEI 529 is
IP22
for all models. IP ratings is only valid
when correctly sized cable glands of the IP rating is applied.
• First numeral, level of protection against contact and foreign objects
2
protection against object size over 12.5 mm (fingers of similar)
• Second numeral, level of protection against water
2
protection against dripping water when tilted up to 15°
IP rating
LRA is the higher average current as measured on
a mechanically blocked compressor tested under
nominal voltage. LRA is printed on the nameplate.
The LRA value can be used as a rough estimation
for the starting current. However in most cases,
the real starting current will be lower. Many
countries have defined limits for the starting
current in domestic use. A soft starter can be
applied to reduce starting current.
The MCC is the current at which the internal
motor protection trips under maximum load and
low voltage conditions.
This MCC value is the maximum at which
the compressor can be operated in transient
conditions and out of the application envelope.
Above this value the overload will switch off to
protect the motor.
MCC (Maximum
Continuous Current)
LRA (Locked Rotor Amp)
Winding resistance
Winding resistance is the resistance between
indicated terminal pins at 25°C (resistance value
+/- 7%).
Winding resistance is generally low and it
requires adapted tools for precise measurement.
Use a digital ohm-meter, a ‘4 wires’ method and
measure under stabilised ambient temperature.
Winding resistance varies strongly with winding
temperature ; If the compressor is stabilised at a
different value than 25°C, the measured resistance
must be corrected with following formula:
a + t
amb
R
tamb
= R
25°C
a + t
25°C
t
25°C
: reference temperature = 25°C
t
amb
: temperature during measurement (°C)
R
25°C
: winding resistance at 25°C
R
amb
: winding resistance at t
amb
coefficient a= 234.5
The Danfoss Heat Pump scroll compressors are
designed to operate without any assistance if
running within the defined nominal voltage. PSC
wiring is sufficient (see below).
Electrical connections
The start winding (C-S) of the motor remains in
circuit through a permanent (run) capacitor.
This permanent (run) capacitor is connected
between the start winding (C-S) and the run
winding (C-R).
PSC wiring
The Max Oper. A is the current when the
compressor operates at maximum load conditions
and 10% below nominal voltage.
This value which is the max rated load current for
the compressor is new on the nameplate.
Max Oper. A can be used to select cables and
contactors.
In normal operation, the compressor current
consumption is always less than the Max Oper. A
value.
Max Oper. A (Maximum
Operating Amp)
C
S
R
Line
Run
Capacitor
13
FRCC.PC.017.A2.02
Application Guidelines
