A Din rail mounted current sensing relay dedicated for DC earth fault monitoring, such as insulation deterioration on a DC system. The unit is supplied complete with a dedicated DC Earth Fault CT type FOX21.CTD, this allows the relay to have two switchable earth fault ranges of 1-20 mA and 10-200 mA. The unit is fitted with four LED's to aid status diagnosis
- Green LED = Auxiliary supply voltage healthy
- Red LED = Output relay energised
- Top Amber LED = Positive leg earth fault
- Bottom Amber LED = Negative leg earth fault
- Both Amber LED's = Open circuit or short circuit between CT & relay (also if Test function is used)
The amber earth fault LED's will start to illuminate at either 1 mA or 10 mA (depending on which range has been set), but the
output relay will not de-energise until the setpoint has been reached, plus any delay “ON” time set, which is adjustable
0.1-10 s. The output relay is fail safe, ie energised when healthy, de-energises on earth fault.
After tripping on an earth fault and the fault level starts to fall below the setpoint it has to fall for a further 2% (hysteresis) plus any delay “OFF” time set before the output relay energises again. This is “AUTO RESET” . However, should the optional latch facility be utilised via a NC link between terminals Y1 & Y2 the NC link will need to be opened or the auxiliary supply removed to facilitate a reset, providing the fault is below the setpoint level plus hysteresis, “MANUAL RESET”.
The relay is also fitted with a relay Test input between terminals Y3 & Y4 via a NO input
Please Note: The YWRI.DEF and its associated CT are designed to monitor insulation breakdown. It must not be used as a safeguard for life protection.