Littelfuse's EL731 AC/DC Sensitive Earth-Leakage Relay

May 17, 2012
Detect Ground Currents; Save a VFD
The EL731 AC/DC Sensitive Earth-Leakage Relay can detect ground currents—even in resistance-grounded electrical systems—all the way do to 0 Hz, making it ideal for protecting variable-frequency drives (VFD) that may operate at low speeds during which AC current approaches DC. The EL731 provides complete range of ground-fault protection in VFDs from 0 to 15000 Hz in one device. It uses a patented approached that enables the relay to detect the location of ground faults and makes it equally useful for AC, mixed AC/DC and DC systems , including low-voltage, 6-pulse VFDs. It is ideal for protecting VFDs operating in resistance-grounded electrical systems that reduce arc-flash hazards. The EL731 can be installed in place of an existing ground fault relay without replacing the current transformer. The relay has a temperature input, metering capabilities, password-protected alarm and trip settings, and an optional Ethernet communications port.Littelfuse's EL731 AC/DC Sensitive Earth-Leakage Relay