| Features
The Wizard Single
Compressor Control is designed to operate a large,
multiple cylinder reciprocating compressor utilizing
ammonia and most halocarbon refrigerants.
Suction
Pressure Control
The WSCC will maintain the
suction pressure as close as the Suction Pressure
Setpoint by turning on/off the compressor and the
unloaders.
The WSCC will initially
start the compressor in the fully unloaded (lowest
capacity) configurations. Should additional capacity be
required, the WSCC, after a calculated delay, will turn
off (add capacity) the next available unloader. Each
unloader will be staged sequentially, in a First On-Last
Off (FILO) sequence.
Once the suction pressure
drops below the suction pressure setpoint, the WSCC will
turn on Unloader stages, thus reducing the compressor
capacity until the compressor is fully unloaded. Only
then, should the pressure continue to be lower than the
setpoint, will the WSCC shut off the compressor.
The compressor will not be
restarted until after a user configurable compressor
restart delay expires. Restart of the compressor will
consist of the compressor fully unloaded.
Condenser
Control
The WSCC operates a single
condenser circuit based upon a fixed head pressure
setpoint. The WSCC activates this control scheme
whenever the compressor is running.
The WSCC will start the
condenser when the head pressure exceeds the setpoint by
three percent of the setpoint value (ie. Setpoint = 200
psi, Condenser start value = 206 PSI). The WSCC will
shut off the condenser when the head pressure drops
below the setpoint by 1.5 percent of the setpoint.
The condenser operates on a
30 sec minimum runtime and off time delay.
Compressor
Cylinder Cooling
The WSCC monitors the
temperature of the compressor head, cycling a relay to
start head cooling should the temperature exceed a user
configurable setpoint. This relay can be used for a head
fan, liquid injection, or a water cooling system.
Monitoring
and Alarming
The WSCC monitors six
separate sensors and activates alarms based upon user
definable alarm setpoints. These alarms include:
Low Suction Pressure -
The WSCC
will shutdown all compressor operations and activate
alarms when the suction pressure is below the Low
Suction Alarm Setpoint for a user defined delay period
High Suction Pressure -
The WSCC
will shutdown all compressor operations and activate
alarms when the suction pressure exceeds the High
Suction Alarm Setpoint for a user defined delay period
Low Oil Pressure
Differential -
The WSCC monitors an oil
pressure transducer and calculates the pressure
differential. The WSCC will shutdown the compressor
operation and activate an alarm when the oil pressure
differential is below the Low Oil Pressure
Differential Alarm Setpoint for a user defined delay
period
High Head Pressure -
The WSCC
monitors the Head/Discharge Pressure Transducer and
will shutdown the compressor operation and activate an
alarm when the head pressure exceeds the High Head
Pressure Alarm Setpoint for a user defined delay
period
Low Head Pressure -
The WSCC monitors
the Head/Discharge Pressure Transducer and activates
an alarm when the head pressure is below the Low Head
Pressure Alarm Setpoint for a user defined delay
period
High Discharge Temperature
- The WSCC
monitors a high temperature sensor mounted to the
discharge manifold. The WSCC activates an alarm when
the discharge temperature exceeds the High Discharge
Temperature Alarm Setpoint for a user defined delay
period
Low Discharge Temperature
- The WSCC
monitors a high temperature sensor mounted to the
discharge manifold. The WSCC activates an alarm when
the discharge temperature goes below the Low Discharge
Temperature Alarm Setpoint for a user defined delay
period
High Oil Temperature -
The WSCC
monitors a high temperature sensor measuring the oil
chamber of the compressor. The WSCC activates an alarm
when the discharge temperature exceeds the High Oil
Temperature Alarm Setpoint for a user defined delay
period
Low Oil Temperature -
The WSCC
monitors a high temperature sensor measuring the oil
chamber of the compressor. The WSCC activates an alarm
when the discharge temperature goes below the Low Oil
Temperature Alarm Setpoint for a user defined delay
period
High Head Temperature -
The WSCC
monitors a high temperature sensor mounted to the
discharge manifold. The WSCC activates an alarm when
the discharge temperature exceeds the High
HeadTemperature Alarm Setpoint for a user defined
delay period
Low Head Temperature -
The WSCC
monitors a high temperature sensor mounted to the
discharge manifold. The WSCC activates an alarm when
the discharge temperature goes below the Low Head
Temperature Alarm Setpoint for a user defined delay
period
System
Standby
The WSCC can be utilized as
a sub-controller for a larger refrigeration control
system. A close signal to the STANDBY input will shut
down all compressor operations. The system will remain
in this standby mode until the input receives an open
signal.
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