DOLD Residual current monitors, for earthed systems VARIMETER RCM

Technical Information and Features

DOLD VARIMETER RCM residual current monitoring for earthed systems.

Residual current monitoring device, also known as RCM (Residual Current Monitor), measures and monitors the residual and fault currents in earthed systems (TN, TT systems). They are used in systems in which a message should be sent in event of an error, but the system should not be switched off. Disturbances resulting from insulation faults will therefore not lead to any unwanted operational downtime, damage to components and higher costs.

Difference to the residual current circuit breaker:
Residual current circuit breaker, so-called RCD (Residual Current Protective Device), always leads to an immediate switch-off. The costly shut-down of the system or data losses can result from this. On the other hand, residual current monitoring devices can display the existing residual current and indicate a case of exceeding the response value and/or switch off as well if required. The system operator in this way receives the information about the existing critical operating conditions early enough and in this way is able to prevent potential personal and component damages or fires. The residual current monitoring device of the VARIMETER RCM family, with external or even integrated residual current transformer, will permanently monitor your system and check it for residual currents. Prevention of insulation disturbances will be indicated early enough for the measures of preventive maintenance and repair to be implemented successfully.

Functioning principle of a residual DOLD current monitor (RCM).

All lines of the outflow which is to be protected (except for the protection line) will go through the residual current transformer. The sum of all currents equals zero in error-free mains; no voltage will be induced in the transformer. If a residual current flows via the ground, the difference in the current will be caused in the transformer. It will be recorded and evaluated by the electronic system of the residual current monitoring device.

The measurement process is applied to residual current monitoring devices which are used with pure AC currents and pulsating DC currents (type A according to IEC/TR 60755). All residual current monitoring devices sensitive to universal current (type B) require implementation of a special measurement process. They are suitable for measurement of all residual current types in electrical systems: AC currents, pulsating and even DC residual currents.
Advantages:
- Simple operation 
- Tripping values can be adjusted via a potentiometer 
- Wire break detection 
- External or integrated residual current transformer 
- Standard or sensitive to universal current
- Customer-specific versions