Carrier AquaEdge 19MV, Руководство по запуску, эксплуатации и техническому обслуживанию

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10
Motor Cooling System
The motor and compressor bearings are cooled by liquid refrig-
erant taken from the bottom of the condenser shell. Refrigerant
flow is maintained by the pressure differential that exists due to
compressor operation. After exiting the condenser shell, the re-
frigerant flows through a moisture indicating sight-glass and an
in-line filter drier. There is a ball valve positioned on each side of
above components for ease of service. After this the refrigerant
is split into several streams which are directed over the motor
windings, thrust bearing, and radial bearings by spray nozzles.
When the chiller is operating there should be turbulent two
phase flow of refrigerant visible in the sight glass. The refriger-
ant collects in the bottom of the motor casing and is then drained
back into the evaporator through the motor refrigerant drainline.
The motor is protected by temperature thermistors embedded in
the stator windings An increase in motor winding temperature
past the motor override set point (200°F [93.3°C]) enables the
capacity inhibit function. The inhibit is released when the tem-
perature is below the motor override set point. If the motor tem-
perature is greater than compressor motor override temperature
plus 10°F (5.5°C) the capacity override will stay active until all
the motor winding temps are less than the motor override set-
point minus 2°F (1.1°C). Note that unit will shut down if any
motor temperature sensor exceeds 220°F (104.4°C). See Fig. 7.
Fig. 7 — Motor Cooling System with Filter Dryer and Moisture Indicator (Standard)
CAUTION
To avoid adverse effects on chiller operation, considerations
must be made to condenser water temperature control. For
steady state operation, the minimum operating refrigerant
pressure differential between evaporator and condenser is
approximately 7 psid (48 kPa) with a maximum evaporator
refrigerant temperature of 65°F (18°C). Consult Chiller
Builder for required steady state operational limits. Inverted
start conditions are acceptable for short durations of time, but
for periods exceeding 5 minutes, a special control solution
strategy should be used to allow the chiller to establish a
minimum refrigerant pressure differential (and thereby
adequate equipment cooling).
EVAPORATOR
CONDENSER
Stg 1
M00
Motor
M00
SUBCOOLER
Filter
Drier
Moisture
Indicator