The Ampcontrol EFL Protection Relay provides earth fault lockout (EFLO) and frozen contactor (FC) protection that is compliant to AS/NZS 2081:2011 sections 7 & 9.
While the outlet’s main contactor is open, the EFL will continually monitor the resistance of the phase conductors to earth, on the load side of the contactor. If this resistance falls below an acceptable level, then the EFL will initiate an EFLO trip, preventing the outlet from being started.
The EFL will also monitor the state of the outlet’s main contactor. If voltage appears on the line when the contactor is open, a Frozen Contactor electrical trip will occur, opening the CBR output. If the main contactor is either open when it should be closed or closed when it should be open a Frozen Contactor logical trip will occur, opening the CBR relay. The CBR relay is intended to be used to open the upstream circuit breaker. A back EMF timer is also provided to inhibit the frozen contactor electrical trip function for a short period after the main contactor is open.
The EFL also has an undervoltage protection function which, if activated, will open the main contactor if the voltage on the load side of the contactor falls below 50% of the selected system voltage.
The EFL is available in two configurations, an internal barrier configuration and an external barrier configuration.
Ampcontrol’s EFL Relay is compliant to AS/NZS 2081:2011 and has been designed for installation on mining outlets that require earth fault lockout and frozen contactor protection. The EFL is capable of being installed on a wide range of system voltages from 110V up to 1.1kV. In addition to EFLO and FC protection, the EFL also offers a selectable undervoltage protection function.
The EFL is for use in non-hazardous areas only, for intrinsically safe applications, use the Ampcontrol EFL-IS Relay (174624) and EFL-IS Barrier (174623).