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CMC TECHNICAL REFERENCE MANUAL
1X36003 Version 2.52
1996-1999 Ingersoll-Rand Company
Date of Issue: 18-Oct-1999
17
Compressor Operating States
Motor Driven Packages
Stopped
+
Waiting
Not Ready
Ready
Compressor
+
+
Rotating
Starting
Loading
Unloaded
MinLoad
Loaded
Full Load
MaxLoad
A-D Unloaded
Surge Unload
Unloading
Coasting
Compressor Operating Methodology
In the following description of compressor operation, the term “state” is used to indicate
what the compressor is doing, or mode of operation, at any given time. These operating
states exist in a hierarchy. For example, the two highest level states are “Stopped” and
“Rotating”. All other states exist at a level below these two states.
Stopped
This state implies that the compressor is or
NOT rotating. It is important to note that this
is an implication only. If the instrumentation is
not working properly or the system is setup
improperly, the compressor could be rotating.
Waiting
After the panel power is energized, the
controller starts the Waiting Timer and does
not allow further User operation until after the
timer expires. This timer is set at the factory
for two minutes (120 seconds) and is not
adjustable. This period allows the
compressor prelube pump to circulate oil
throughout the casing and prevents restarting
while the compressor is coasting down
during an electrical interruption.
Not Ready
When in this state, the compressor is “Not
Ready To Start”. This state is entered when
the Waiting Timer has expired and any time
that a compressor trip has been identified or
a stop command has been issued. A very
common and quite often overlooked reason for the compressor being “Not Ready” is when
the Emergency Stop push button has been engaged. This state can exist indefinitely.
Ready
Similar to the previous state, this state could be redefined as “Ready to Start”. This state is
entered when all compressor permissive functions have been satisfied. This state can exist
indefinitely.
Rotating
This mode does not necessarily mean that the compressor is actually rotating. It means that
it is rotating or rotation is pending and expected.
Starting
Any time after the compressor is ready and a start command is given, this state is entered.
The goal for this period is to get the compressor to rated speed and running unloaded.
“Starting” is allowed for only the Start Timer period and is adjustable. This time period is