The Ampcontrol EFL-IS Protection Relay provides earth fault lockout (EFLO) and frozen contact (FC) protection that is compliant to AS/NZS 2081:2011 sections 7 & 9.
The EFL IS Relay and EFL-IS Barrier are IECEx certified as Ex ia, provided that the conditions of use in the certification are adhered to.
While the outlet’s main contactor is open, the EFL-IS relay will use an intrinsically safe signal to continually monitor the resistance of the outlet’s phase conductors to earth. If this resistance falls below an acceptable level the EFL-IS relay will initiate an EFLO trip, preventing the outlet from being started.
The EFL-IS relay will also monitor the state of the outlet’s main contactor. If voltage appears on the line when the contactor is open, a Frozen Contact electrical trip will occur. This FC output relay is intended to be used to open the upstream circuit breaker. If the main contactor is either open when it should be closed or closed when it should be open a Frozen Contact logical trip will occur, initiating an upstream circuit breaker trip. A Back EMF timer is also provided to inhibit the frozen contact electrical trip function for a short period after the main contactor is open.
The EFL-IS relay also has an undervoltage protection function which, if activated, will open the main contactor if the outlet voltage falls below 50% of the selected system voltage.
The EFL-IS relay monitors the line voltage via the externally connected EFL-IS barrier. The external barrier is supplied with high voltage flying lead connections to allow the high voltage terminations to be made.
The Ampcontrol EFL-IS relay has been designed for installation on mining outlets supplying hazardous area equipment that require earth fault lockout and frozen contact protection.
The Ampcontrol EFL-IS relay is IECEx Ex ia certified and is compliant to AS/NZS 2081:2011 sections 7 & 9. The EFL-IS 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-IS also offers a selectable undervoltage protection function.
