Emerson VSG & VSSG, Software Manual

Page: 34 / 86

34
Compressor Setpoints and Alarms
· Prelube Oil Pressure – If the oil pressure does not
rise above the reset setting for a time exceeding
the Minimum Compressor Prelube Time and
the pump runs longer than the Prelube Pump
Time Limit, an alarm or trip will occur. These
time limits are set on the Compressor Timer
Setpoints screen. Prelube oil pressure is defined
as the amount that the oil pump drives manifold
pressure above the discharge pressure.
· Low Oil Pressure – This is the running oil pres-
sure safety. An alarm or trip will be active if the
oil pressure should drop below the setpoint
value. This occurs once the Oil Pressure Bypass
timer has expired. The time limit is set on the
Compressor Timer Setpoints screen. For the
single screw compressor, oil pressure is defined
as manifold pressure minus suction pressure.
· High Filter Differential Pressure Start – This
safety setpoint is active when the compressor is
in the start cycle. An alarm or trip will be active
if the filter inlet pressure exceeds the filter outlet
pressure by the setpoint value.
· High Filter Differential Pressure Run – This safety
setpoint is active when the compressor is in
the run cycle. An alarm or trip will be active if
the filter inlet pressure exceeds the filter outlet
pressure by the setpoint value.
· High Motor Amps – This safety setpoint is ac-
tive after the Volume Decrease At Start Timer
expires. This timer is not user settable, and in
standard applications, is 15 seconds. A trip will
occur if the motor amperage exceeds the safety
setpoint value. The setpoint should be set at
125% of the motor full load amperage.