Daikin MAGNITUDE WME-D, Установка, эксплуатация и обслуживание, Страница: 18 / 56

ELECTRICAL DATA
MAGNITUDE WME-D MAGNETIC BEARING CHILLER DAIKIN APPLIED
18
Use with On-Site Generators
All Magnitude Model WME chillers have their compressors
operated with variable frequency drives and, if the unit has two
compressors, the compressors start sequentially in the normal
start/load sequence. These features make Magnitude chillers
especially appropriate for use in applications where they may
be required to run with on-site electrical generators. This is
particularly true when the generators are used for temporary
power when the utility power is lost.
Generator Sizing
Natural gas and diesel generators are sensitive to the peak
current loads of the chiller. Although the normal VFD start
sequence does not require these peak values of current,
certain dynamic conditions such as changes in water flow and
temperature or momentary power interruptions can cause high
peak electrical currents. Use the electrical data either on the VFD
data plate or supplied with the chiller performance rating sheet
– obtained from the Daikin Applied sales office – for generator
sizing purposes. The referenced data will show the RLA and
LRA, which is for each compressor. It is important to size the
generator to handle the LRA value.
WARNING
Generator must be sized by an electrical engineer familiar with
generator applications.
Transfer Back to Grid Power
Due to the special VFD incorporated in all WME chillers and the
system’s inherent ride-through capabilities, transfer from grid
power to stand-by generator power and back to grid power can
be done at any time. The duration of power interruption during
the transfer process will determine how the chiller will respond.
While the compressor rotor is still spinning at adequate speed,
power is generated internally to keep the bearings and all control
electronics operating. Power interruptions of various durations
will cause different restart scenarios as described below.
1 . Short: Interruptions of only a few seconds will allow a
running compressor to return to operating speed almost
immediately.
NOTICE
If the operating pressure ratio is high at the time of interruption,
there may be a short delay in return to operating speed
2 . Medium: For interruptions that cause the compressor to
coast down below about 3500 rpm (but still generating
control power), the compressor will continue coasting to a
stop, and then restart.
3 . Long: Once the compressor coasts nearly to a stop,
control power is lost and the controllers must reboot
normally when either grid power or emergency generator
power is reinstate.
NOTICE
If the RapidRestore option is installed, the time required to restart
is reduced to only a few seconds.
Building Automation Systems (BAS)
All MicroTech controllers are capable of BAS communications,
providing easy integration and comprehensive monitoring,
control, and two-way data exchange with open standard
protocols such as Modbus
®
or BACnet
®
.
Daikin Applied unit controllers strictly conform to the
interoperability guidelines of BACnet
®
International.
Protocol Options
The following protocol options are available:
• BACnet
®
MS/TP
• BACnet
®
IP
• Modbus
®
RTU
The BAS communication module can be ordered with the chiller
and factory-mounted or can be field-mounted at any time after
the chiller unit is installed. Connection to the chiller for all BAS
protocols will be at the unit controller. An interface card or
module, depending on the protocol being used, will have been
factory installed in the unit controller if so ordered, or it can be
field installed.
If an interface module was ordered, the appropriate BAS
interface installation manual was shipped with the unit. If
necessary, contact your local Daikin Applied sales office for a
replacement manual or obtain one from www.DaikinApplied.com .
BAS Connection
If BAS module is needed for BACnet or Modbus, the UE1 module
will be replaced with the BUE1 module shown in Figure 26 for
wiring.