The ECD is an intrinsically safe electrical protection relay designed for operation in underground coal mining applications.
The ECD provides earth continuity protection in accordance with AS/NZS 2081:2011 ensuring the integrity of the earth connection through a trailing or reeling cable is maintained.
The ECD relay is based on microprocessor digital logic, and features a user friendly LED and switch interface. It is installed within a compact, DIN rail mounted unit with pluggable connectors that can easily be changed out in the event of a problem with the relay.
The relay contains an internal IS barrier.
Typically the ECD relay will be connected to the pilot conductor of a trailing or reeling cable. With the pilot conductor terminated to earth through a diode, the relay measures the resistance of the pilot-earth loop (series resistance), to ensure the integrity of the earth conductors, and the pilot to earth resistance (shunt resistance), to ensure the integrity of the pilot-earth loop. If these tests fail the ECD will trip, de-energising its output relay which can be used to switch a contactor, circuit breaker or for signalling.
The ECD can be configured for latching or non-latching operation and has a remote start option.
The ECD relay can also be used as an IS interlock with the pilot terminal connected to a circuit that passes through interlocks and switches.