Danfoss Performer SM Series, Выбор и руководство по применению

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V
avg
= Mean voltage of phases 1, 2, 3.
V
1-2
= Voltage between phases 1 & 2.
V
1-3
= Voltage between phases 1 & 3.
V
2-3
= Voltage between phases 2 & 3.
| V
avg
- V
1-2
| + | V
avg
- V
1-3
| + | V
avg
- V
2-3
|
2 x V
avg
% voltage
imbalance
=
x 100
22
A high pressure (HP) safety switch is
required to shut down the compressor
if discharge pressure exceeds the
values shown in the table below.
The high pressure switch can be set
to lower values depending on the
application and ambient conditions.
To prevent cycling around the high
pressure limit, the HP switch must be
placed in a lockout circuit or it must
require manual reset. If a discharge
valve is used, the HP switch must be connected to the service valve gauge
port, which must not be isolated.
NOTE: Because the power consumption
of scroll compressors is almost directly
proportional to discharge pressure,
the high pressure control can be
used to indirectly limit the maximum
current draw. A high pressure control
used in this manner, however, can
never replace an external overload
protector.
sYsteM design RecoMMendations
*LP safety switch shall never be bypassed.
** Recommended pump-down switch settings: 22 psi (R-22, R-407C, R404A) or
14.5 psi (R-134a) below nominal evaporating pressure.
Operating voltage limits are shown
in the table on page 12. The voltage
applied to the motor terminals must
lie within these table limits during
both start-up and normal operations.
The maximum allowable voltage imbalance is 2%. Voltage imbalance
causes high amperage on one or
more phases, which in turn leads
to overheating and possible motor
damage. Voltage imbalance is given
by the formula:
Voltage imbalance
High and low
pressure protection
High pressure
A low pressure (LP) safety switch
must always be used. Deep vacuum
operation of a scroll compressor can
cause internal electrical arcing and
scroll instability. Performer® scroll
compressors exhibit high volumetric
efficiency and may draw very deep
vacuum levels, which could induce
such a problem. 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 be either a manual 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
R-22 R-407c R-134a R404a/R507a
Working pressure range high side psig 158 - 402 152 - 422 97 - 293 184 - 464
Working pressure range low side psig 20 - 100 16 - 93 9 - 7 29 - 106
Maximum high pressure safety switch setting psig 406 428 297 471
Minimum low pressure safety switch setting * psig 7 7 7 7
Minimum low pressure pump-down switch setting ** psig 19 14 7 26