© Danfoss | Climate Solutions | 2022.03
Electrical data, connections and wiring
Three phase electrical
characteristics
Compressor model
LRA
Max. operating current
Winding resistance
A
A
Ω
Motor voltage code 4
380-415 V/3 ph/50 Hz
MLM/MLZ090
147
26
0.92
MLM/MLZ130
260
44
0.52
MLM/MLZ160
215
47
0.62
MLM/MLZ200
270
58
0.52
MLM/MLZ240
300
70
0.41
MLZ/MLM116
175
35
0.914
Locked Rotor Amp value is the higher average
current as measured on mechanically blocked
compressor tested under nominal voltage. The
LRA value can be used as rough estimation for
the starting current. However in most cases, the
real starting current will be lower. A soft starter
can be applied to reduce starting current.
LRA (Locked rotor amp)
The max. operating current is the current when
the compressor operates at maximum load
conditions and 10% below nominal voltage.
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. operating current
Winding resistance is the resistance between
phases 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 stabilized ambient temperature.
Winding resistance varies strongly with winding
temperature. If the compressor is stabilized
at a different value than 25°C, the measured
resistance must be corrected using 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 tamb
Coefficient a = 234.5
Winding resistance
The compressor terminal box according to IEC529 is IP54 for all models when correctly sized IP54 rated
cable glands are used.
First numeral, level of protection against contact and foreign objects
5
- Dust protected
Second numeral, level of protection against water
4
- Protection against water splashing
The temperature inside the terminal box may not
exceed 70°C. Consequently, if the compressor
is installed in an enclosure, precautions must
be taken to avoid the temperature around the
compressor and in the terminal box from rising
too much. The installation of ventilation on the
enclosure panels may be necessary. If not, the
electronic protection module may not operate
properly. Any compressor damage related to this
will not be covered by the Danfoss warranty. In
the same manner, cables must be selected in a
way to ensure that terminal box temperature
does not exceed 70°C.
IP rating
Terminal box
temperature
16
AB243586442698en-000601
Application Guidelines
Single compressors