2200LZJE-HO-C6-N_2013.12.
Chapter 1 Safety
Compound 2-stage Screw Compressor 2016**C
1.4
Safety Devices
1-7
1.4.3 Compressor Protective Devices
Be sure to adjust the set values and check operation of the protective devices at
the test run.
Overview/Function/Purpose
These protective devices are used to protect this product.
Protecting from discharge temperature rise (DT)
This device stops the compressor operation when the discharge temperature of the
compressor exceeds the set value.
Install a temperature sensing port to the discharge pipe.
Protecting from oil temperature rise (OT)
This device stops the compressor operation when the oil temperature of the compressor
exceeds the set value.
Install a temperature sensing port to the unit's oil supply pipe (after the oil cooler).
Protecting from high pressure (HP)
This device stops the compressor operation when the discharge pressure abnormally rises
due to compressor misoperations or stoppage of cooling water supply to the condenser.
This device prevents explosion of the equipment and components.
Install a pressure sensing port to the discharge pipe.
Protecting from intermediate pressure (IP)
This device controls the compressor appropriately when the intermediate pressure exceeds
the set value.
In some cases, this device stops the compressor operation.
Install a pressure output port to the unit's intermediate gas pipe (or compressor's intermediate
gas pressure output port).
Protecting from suction pressure drop (LP)
This device stops the compressor operation when the suction pressure becomes below the
set value.
Install a pressure sensing port to the suction pipe.
Protecting from oil pressure (OP)
This device stops the compressor operation when refrigerant oil supply is not sufficient, the oil
filter is clogged, the refrigerant is mixed into the lubricant, and oil supply pressure difference
(from discharge pressure) becomes below the set value.
This device is to protect the compressor from wear and burnout.
Install a pressure sensing port to the unit's oil supply pump (after the oil pump) and the
discharge pipe.
Protecting from motor overcurrent (OCR)
This device controls the compressor appropriately when the current exceeds the set value. In
some cases, this device stops the compressor operation.
This device is normally installed in the compressor operation controller.