NEH Conductive Suspended Electrode Limit Switch

KOBOLD limit switches model NEH are used for level monitoring and pump control of conductive liquids. The instruments operate on the conductive principle. 

A low a.c. voltage is applied between the conductive side of the tank or the earth electrode (longest electrode) and a switching point electrode.

If the conductive medium touches the electrodes, a negligible alternating current flows across the electrodes and the conductive medium to the electrode relay. Suspended electrodes are ideally suited for installation when space is at a premium. 

The relay amplifies the alternating current and operates a switching relay or a pump controller. An electrode relay of type NE-104 is required per switch point for signaling. 

For minimum/maximum control two switching point electrodes must be connected to the relay. Relay NE-304 operates as two single relays (NE-104).