Insufficient Oil Pressure Protection; Motor Overheat Protection; High Discharge Temperature Protection; Locked Rotor Protection - Emerson CoreSense Technical Information

3.3

Insufficient oil pressure protection

The CoreSense™ Diagnostics module replaces the mechanical oil pressure switch. Furthermore, it provides the
added value of communication for insufficient oil pressure warning and lockouts via LED flash codes and/or a
supervisory pack controller. Total insufficient oil pressure time for the compressor is stored and accumulated in the
module memory.
CoreSense™ Diagnostics will issue a warning when oil pressure differential falls below 0.48-0.62 bar for
4 seconds.
Once the oil pressure differential falls below 0.48-0.62 bar for 2 minutes (120 sec), the module will shut the
compressor off and a "low oil pressure lockout" will be reported. Before using the reset button, troubleshooting
needs to be done to understand the failure. The compressor will switch back on once the reset has been activated
either manually or remotely through the communication network, or when power has been cycled to the
CoreSense™ module. This feature is not applicable to Copeland compressor models 4MTL (Stream CO2
compressors) as these have no positive oil pump fitted and are "splash" lubricated.
3.4

Motor overheat protection

Using Positive Temperature Coefficient (PTC) sensors on 4M* and 6M* Stream compressor models, the
CoreSense™ Diagnostics module provides motor overheating protection. The CoreSense™ Diagnostic module
replaces the Kriwan module INT69TM.
Alarm condition:
 Trip condition: PTC Resistance > 4.5 kΩ;
 Reset condition: PTC Resistance < 2.5 kΩ; 5 min time delay.
3.5

High discharge temperature protection

Discharge temperature protection is provided using a NTC sensor in the compressor cylinder head. The sensor is
pre-installed at the factory and connected to the module. CoreSense™ will protect the compressor from high
discharge temperature conditions. If the temperature sensor detects a discharge temperature higher than 154°C,
the CoreSense™ will shut off the compressor until the temperature cools down to an acceptable level (about
130°C).
Either trip or lockout alarm can be selected by user. Default is trip alarm.
 Trip/lockout value ≥ 154°C for 2 sec.

Trip alarm: Automatic reset after 2 minutes; discharge temp < 130ºC.

Lockout alarm: Manual reset is necessary.
3.6

Locked rotor protection

Appears when the rotor is mechanically seized. Locked rotor current is expected to decrease within 4 seconds after
the motor comes up to speed.
3.7

Missing phase protection

If any one of the 3 power phases is missing immediately after the compressor contactor is energized, a single-
phasing condition exists.
The maximum response time shall be 1.2 seconds from the time of contactor energization.
Alarm condition: If any phase voltage < 84% of max of 3 input voltages for a period of 1 second.

Trip time: 5 minutes with automatic reset.

Lockout condition: Appears after the 10 consecutive trip alarms. Manual reset (using reset button below
the module or using remote reset by pack controller).
In the case of a part winding motor this feature is detectable for primary winding only. Missing phase, voltage
imbalance and low voltage are not detectable for the secondary winding. A missing phase can be detected during
start-up, but not while the motor is running.
3.8

Low voltage protection

Appears when there is a low supply voltage.
Technical Information
D7.21.2/1011/E
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