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CMC TECHNICAL REFERENCE MANUAL
1X36003 Version 2.52
1996-1999 Ingersoll-Rand Company
Date of Issue: 18-Oct-1999
Control Electrical Package
The Control Electrical Package consists of a Control Transformer, Prelube Pump Starter,
Oil Heater Contactor(s) and Transient Voltage Surge Suppressor. This option allows the
customer to bring a single source of electrical power to the compressor to run all of the
compressor package accessories; thereby, making compressor installation easier.
Stage Data Package
For monitoring of interstage pressure and temperatures, the Stage Data Package can be
added. As standard, the CMC comes with temperature readout, alarm and trip for the next to
last compression stage and compressor discharge pressure indication. When selected,
each stage gets temperature and pressure measurements on the downstream side of each
stage's cooler. For compressors without built-in aftercoolers, the last stage diffuser
temperature is measured. Each temperature has readout, alarm and trip capability while the
pressures are readout only.
Alarm Horn
The optional alarm horn sounds any time there is an alarm or trip situation. The horn output
will pulse for an alarm and remain constant for a trip. This allows the operator to distinguish
between each fault type without viewing the OUI. The horn silence push-button is located on
the CMC faceplate to silence any audible devices connected to the CMC board.
Running Unloaded Shutdown Timer
The intent of this option is to save energy by shutting the compressor off during extended
periods of unloaded operation. When the running unloaded shutdown timer is enabled with
the RUNNING UNLOADED SHUTDOWN TIMER DISABLED/ENABLED selector switch, the
auto-dual control mode should be selected, this provides for automatic unloading of the
machine during periods of low demand.
Water Solenoid Post Run Timer
This optional panel function is used to shut off water flow to the air and oil coolers after the
compressor is stopped. It is accomplished by sending a signal to close the solenoid
operated water valve(s).
Panel Mounted Wye-Delta Starter
Main motor starter enclosed in the CMC panel. This feature allows the customer to wire the
compressor from a single source; thereby, eliminating most electrical wiring and starter
installation expense. These starters are available for compressors with motors up to 350 HP
and 575 Volts.
N.O. Contact for Remote Indication of Common Alarm and
Trip
A normally open contact for individual remote indication closes whenever an alarm or trip
occurs. This allows a customer to have remote indication of compressor alarm, trip or both.
Power Regulating Constant Voltage Transformer
If the electrical power supplied to the CMC varies more than ten percent, this transformer
must be added to bring the voltage within the specification requirements.