24
AB243586442172en-001401
Operating conditions
Motor supply
SH scroll compressors can be operated at
nominal voltages as indicated section “Motor
voltage”. Under-voltage and over-voltage
operation is allowed within the indicated voltage
ranges. In case of risk of under-voltage operation,
special attention must be paid to current draw.
The operating envelope for SH scroll compressors
is given in the figure below, where the
condensing and evaporating temperatures
represent the range for steady-state operation
at nominal voltage. Under transient conditions,
such as start-up and defrost, the compressor may
operate outside this envelope for short periods.
The operating limits serve to define the
envelope within which reliable operations of the
compressor are guaranteed:
• Maximum discharge gas temperature: +135°C,
• A suction superheat below 5 K is not
recommended due to the risk of liquid flood
back,
• Maximum superheat of 30 K,
• Minimum and maximum evaporating and
condensing temperatures as per the operating
envelopes.
SH compressors can be applied from -35°C to
55°C ambient temperature for SH090-105-120-
140-161-184 and 51°C ambient temperature for
SH180-240-295-380-485. The compressors are
designed as 100% suction gas cooled without
need for additional fan cooling. Ambient
temperature has very little effect on the
compressor performance.
Application envelope
Compressor ambient
temperature
POE oil
Polyolester oil (POE) is miscible with HFC's
(while mineral oil is not), but has to be evaluated
regarding lubrication ability in compressors.
POE oil has better thermal stability than
refrigerant mineral oil.
POE is more hygroscopic and also holds moisture
more tight than mineral oil.
It also chemically reacts with water leading to
acid and alcohol formation.
In case of enclosed fitting and high ambient
temperature, it is recommended to check the
temperature of power wires and conformity to
their insulation specification.
In case of safe tripping by the internal
compressor overload protection, the compressor
must cool down to about 60°C before the
overload will reset. A high ambient temperature
can strongly delay this cool-down process.
Although the compressor itself can withstand
low ambient temperature, the system may
require specific design features to ensure safe
and reliable operation. See section ‘Specific
application recommendations’.
High ambient temperature
Low ambient temperature
10
15
20
25
30
35
40
45
50
55
60
65
70
75
-35
-30
-25
-20
-15
-10
-5
0
5
10
15
20
Evaporating temperature (°C)
Co
ndensing temperature
(°
C)
SH= 11.1K
SH = 5 K
SH= 30K
Application Guidelines
Summary of Contents for SH485
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