Frick RWF, Установка, эксплуатация и обслуживание

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RWF ROTARY SCREW COMPRESSOR UNITS
INSTALLATION
S70-600 IOM
Page 10
noid on the PRR unit and the liquid feed solenoid on the DX
vessel off of a common signal to avoid liquid overfeed on
the DX economizer system.
If multiple compressors are operated with a common econo-
mizer vessel, it is necessary to install a back-pressure regu-
lator valve with an electric shutoff option in the vapor line
piped to the compressor's economizer port. If an electric
shut-off is not installed in the economizer vapor line, valve
HV-2 must remain closed to avoid a gas bypass from the
economizer line through the suction check valve bypass,
back to the suction line on a compressor that is shut down.
ECONOMIZER LOAD BALANCING
The most energy efficient manner to operate an economizer
system, when using multiple compressors on a common
economizer vessel, is to take as much of the flash gas as
possible to the compressors that are fully loaded. This can
be done in at least two ways.
1. Use the economizer output from the microprocessor to
turn off a solenoid, or to actuate the electric shutoff option
on a back-pressure regulator, based on percent of slide valve
travel. This will direct all the flash vapor to the other loaded
compressors.
2. A dual-setpoint back-pressure regulator valve can be used
in each of the individual economizer vapor lines. When a
compressor is running near full load, the BPR valve will op-
erate on the desired setpoint, or basically wide open, to mini-
mize pressure drop in the line. When one compressor un-
loads below the slide valve position where the economizer
output on the microprocessor turns on, the dual-setpoint fea-
ture of the regulator can be actuated by this output to con-
trol the pressure, on the vessel side of the regulator, to be a
few psi higher. Consequently, the flash gas will be sent to
the loaded compressors first, until they can’t handle all the
vapor and the pressure in the vessel starts to rise. Then,
some of the vapor will go to the unloaded compressor to
help maintain the vessel at the desired pressure. An example
of a back-pressure regulator with electric shutoff and the
dual-setpoint feature is an R/S A4ADS.
ELECTRICAL
NOTE: Before proceeding with electrical installation, read
the instructions in the section “Proper Installation of
Electronic Equipment in an Industrial Environment”.
RWF units are supplied with a QUANTUM control system.
Care must be taken that the controls are not exposed to
physical damage during handling, storage, and installation.
The single-box control door must be kept tightly closed to
prevent moisture and foreign matter from entry.
NOTE: All customer connections are made in the single-
box control mounted on the oil separator. This is the
ONLY electrical enclosure and it should be kept tightly
closed whenever work is not being done in it.
MOTOR STARTER PACKAGE
SBC Board damage may occur
without timer relay installed in con-
trol panel as shown in Starter Wir-
ing Diagram. All Frick motor starter packages have the
timer relay as standard.
Motor starter and interlock wiring requirements are shown
in the Starter Wiring Diagram. All of the equipment shown
is supplied by the installer unless a starter package is pur-
chased separately from Frick . Starter packages should con-
sist of:
1. The compressor motor starter of the specified HP and
voltage for the starting method specified (across-the-line,
autotransformer, wye-delta, or solid state).
NOTE: If starting methods other than across-the-line are
desired, a motor/compressor torque analysis must be
done to ensure that sufficient starting torque is avail-
able, particularly in booster applications. Contact FRICK
if assistance is required.
2. If specified, the starter package can be supplied as a com-
bination starter with circuit breaker disconnect. However, the
motor overcurrent protection/disconnection device can be
applied by others, usually as a part of an electrical power
distribution board.
3. The oil pump starter with fuses, or in the case where the
compressor motor is a different voltage from the oil pump
motor, with a circuit breaker disconnect suitable for sepa-
rate power feed.
4. A 2.0 KVA control power transformer (CPT) to supply 120
volt control power to the microprocessor control system and
separator oil heaters is included. If environmental conditions
require more than the usual two 500 watt oil heaters, an
appropriately oversized control transformer will be required.
If frequent power fluctuations are anticipated or extremely
noisy power lines are encountered, a regulating control trans-
former should be considered. Contact FRICK for assistance.
5. For customer-supplied across-the-line starters, a shunt-
ing device must be installed across the Current Transformer
(terminals 3 & 4).
If the shunting device is not in-
stalled, the Analog I/O board on the
Quantum panel may be severly
damaged at start-up (see Figure 10).
Figure 10 - STARTER WIRING DIAGRAM