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CMC TECHNICAL REFERENCE MANUAL
1X36003 Version 2.52
1996-1999 Ingersoll-Rand Company
Date of Issue: 18-Oct-1999
81
4. Reset the governor to clear any trip signals. This may be accomplished with the digital
output (Reset – Momentary). If an electronic governor exists, a discrete output signal
(Common Trip) is sent from the governor to a discrete input signal on the CMC when the
governor needs to trip the compressor. If no electronic governor exists, a jumper must
be installed on the CMC board.
5. When NO Trips exist (compressor and turbine), the CMC energizes the turbine’s trip
and throttle valve (TTV) solenoid. This is accomplished through a discrete output (Driver
Permissive) from the CMC to the TTV solenoid.
6. At this point, the compressor is NOT READY, Driver Disabled.
7. When the TTV solenoid is energized, the turbine trip valve can be latched.
8. When the turbine trip valve is manually latched, the turbine trip valve’s limit switch will be
energized. This signal is sent to a discrete input (Trip and Throttle Valve Limit Switch) on
the CMC.
9. When the limit switch is energized and no stop command is pending, the compressor
will be READY. This state may be maintained indefinitely.
10. The Start Key is pressed on the compressor. The digital output (CR1) is energized to
actuate the solenoid operated steam valve and the digital output (Start – Momentary) is
energized. A timer (five minute maximum) is started. At this point, enough steam should
be applied to the turbine to get the speed above the zero speed offset. This period is
ACCELERATE-1.
11. Once the zero speed offset has been established, a one minute timer is provided to
prevent compressor pinion damage from rotating the pinions at too low a speed for an
excessive time. The compressor bearings are designed to have a minimum oil film
pressure created by a minimum rotating pinion speed. Therefore, we must not stay at
Accelerate-1
Accelerate-2
Slow Rolling
Starting
Accelerate-1
Accelerate-2
Starting
Accelerate-1
Starting
Adaptive Starting
TM
Techniques
Zero Speed Offset (15 rpm)
Minimum Slow Roll (25%)
Maximum Slow Roll (50%)
Low Trip (93%)
(0%)
SPEED