The CFM is a self-resetting cable monitoring device for the detection of cable errors.

The device is used for insulation monitoring of cable systems in DC Systems. The cable monitoring device monitors the standard insulation between conductor and shield, shield and conductor as well as the additional monitoring of interruptions of the shield.

There are two potential-free changeover contacts available for the reporting. The device is integrated in a plastic housing that is made for the mounting on top-hat or wall railways.

The optional, external display unit makes it possible to depict the critical- and insulation resistance.

To obtain defined conditions, electrical resistances have to be switched parallel to the supervised insulation sections. These electrical resistances are in such a dimension that the nominal shield standing voltage is restricted to 40 V and the measuring current may not exceed approx. 1 mA trough the shield. The interruption of the shield leads either to the report “ground fault” (shield-ground) or “inner fault” (conductor-shield).

In case of failure of the track voltage this is signalled at a potential-free contact.

For further information please download the datasheet: