- Three Phase AC Systems

The GM420 measures the integrity of the ground conductor for AC and offline systems via its resistance, as well as extraneous voltages that may exist between the two measuring terminals. Two seperate alarms allow for the simultaneous measurement of these two alarms. Each of the two alarms has a seperate Form C SPDT contact for use with external LEDs, contactors, PLCs, and many other applications. Contacts may be set for normally energized or de-energized operation.

The setpoint range is adjustable from 0 Ω to 100 Ω. In addition, an extraneous voltage alarm can be toggled, activating when the voltage between the two measuring terminals meets or exceeds 12 V.

The GM420 has three seperate, adjustable time delays (start-up, response, on release) from 0 to 99 seconds. Setpoint and hysteresis ranges allow for application-tailored sensitivity. A fault memory toggle allows alarms to either latch or auto-reset after it has cleared.

Values are read and settings are changed via a digital LCD display. Three pushbuttons allow for navigation through built-in menus. History memory stores the last received alarm. A password protection may also be set.

These devices are suited for installation into standard distribution panels according to DIN 43 871 and for quick assembly onto support rail according to DIN EN 50 022 or for screw mounting.