Compressor Setpoints And Alarms - Emerson Vission Control Manual

· Prelube Oil Pressure – If the oil pressure does
not rise above the reset setting for a time exceed-
ing 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 pres-
sure 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 Com-
pressor Timer Setpoints screen. For the single
screw compressor, oil pressure is defined as mani-
fold pressure minus suction pressure.

Compressor Setpoints and Alarms

· 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 out-
let 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 out-
let 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.
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