Cryomech LNP-40, Installation, Operation And Routine Maintenance Manual

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Specifications
5-19
5.8 Description of the electrical protection device (option)
The optional electrical protection device (EPD) is designed to protect against phase loss
(single phasing), phase reversal (incorrect sequence), unbalanced voltage (unequal
phase to phase voltages), high voltage, low voltage, and short cycling. If any of the above
mentioned faults occurs, the EPD will shut the helium compressor down. Upon correction
of the fault(s) a 5-minute restart delay begins, after which the system will restart
automatically.
The EPD is housed in a wall mountable electrical enclosure. The enclosure is fitted with
an input power cord and 5 pin connector that attaches to a mating receptacle located on
the helium compressor.
Figure 5-11: Electrical protection device
Electrical Protection Module
The monitoring relay ensures that the voltage supply to the helium compressor is within
its acceptable limits. If a fault condition occurs the output relay is de-energized, shutting
down the LNP. See the next section for detailed information of the monitoring relay.
LED Indicators
The LED indicators are used to display the existing status of the module and any faults
that have occurred.
Memory Selector
The memory selector is used to read or clear the memory of the module.
Fuse Block
The fuse block is fitted with three fuses to protect the monitoring relay.
Fuse Block
Fuse Cover with
Indicator Light
Electrical
Protection Module
LED Indicators
Memory Selector