Danfoss Performer SH090 User Manual

APPLICATION GUIDELINES
FRCC.PC.007.B5.02
27
Cycle rate limit
A low-pressure (LP) safety switch must be used.
Deep vacuum operations of a scroll compressor
can cause internal electrical arcing and scroll in-
stability. Performer SH Scroll compressors exhibit
high volumetric effi ciency and may draw very low
vacuum levels, which could induce such a prob-
lem. The minimum low-pressure safety switch
(loss-of-charge safety switch) setting is given in
the following table. For systems without pump-
down, the LP safety switch must either be a man-
ual lockout device or an automatic switch wired
into an electrical lockout circuit. The LP switch
tolerance must not allow for vacuum operations
of the compressor. LP switch settings for pump-
down cycles with automatic reset are also listed
in the table below.
Low pressure
OPERATING CONDITIONS
Danfoss recommends a restart delay timer to limit
compressor cycling. The timer prevents reverse
compressor rotation, which may occur during
brief power interruptions.
The system must be designed in a way that guar-
antees a minimum compressor running time of 2
minutes so as to provide for suffi cient motor cool-
ing after start-up along with proper oil return.
Note that the oil return may vary since it depends
upon system design.
There must be no more than 12 starts per hour, a
number higher than 12 reduces the service life of
the motor-compressor unit. A three-minute (180-
sec) time out is recommended.
Note that these two diff erent low pressure switch-
es also require diff erent settings. The low pressure
pump down switch setting must always be within
the operating envelope, for example 2.3 bar for
R410A. The compressor can be operated full time
under such condition. The minimum low pressure
safety switch setting may be outside the normal
operating envelope and should only be reached
in exceptional (emergency) situations, for exam-
ple 1.5 bar for R410A.
Please contact Danfoss Technical Support for any deviation from this guidelines.
T T
TH
T
H
KA
A1
A2 A3A1
180 s
A2
KA
~
~
Pressure settings R410A
Working pressure range high side bar (g) 13.5 - 44.5
Working pressure range low side bar (g) 2.3 - 11.6
Maximum high pressure safety switch setting bar (g) 45
Minimum low pressure safety switch setting * bar (g) 1.5
Minimum low pressure pump-down switch setting ** bar (g) 2.3
* LP safety switch shall never be bypassed and shall have no time delay.
** Recommended pump-down switch settings: 1.5 bar below nominal evap. pressure with minimum of 2.3 bar(g)

Danfoss Performer SH090 Specifications

General

Brand	Danfoss
Model	Performer SH090
Category	Air Compressor
Language	English