The protective conductors (PE) in systems with servo and frequency inverters are not currentless!

Various measures (use of line filters, use of shielded motor cables, etc.) must be taken in order to meet CE conformity and the binding protection regulations of the low-voltage, EMC and machine directive. Cable shields, interference suppression capacitors and motor windings represent parasitic capacitances. In a fault-free system state, operational leakage currents flow through these parasitic capacitances to the protective conductor or via other conductive parts to the earth potential.

Manufacturers and operators of devices and systems are fundamentally obliged to protect people against electric shock and to switch off sources of danger that could cause fires. Exactly these hazards can be caused by fault currents and must therefore be included in the safety considerations.

For personal and fire protection in these systems, AC/DC sensitive residual current circuit breakers (RCCB) with rated residual currents of 30 mA are used. These rated residual currents are reached or even exceeded in many electrical systems during normal operation. In the past, the response to such problems was the impermissible expansion/bridging of the protective device or the lowering of the prescribed protective goals by using residual current devices with higher rated residual currents (e.g. 300 mA instead of 30 mA).

Currents that are caused by insulation faults or by the human body (e.g. through contact) are fault currents. Only these currents should trip an AC/DC sensitive RCD and lead to the shutdown of a system.

This important distinction between operational leakage currents on the one hand and fault currents due to human contact or insulation problems on the other hand cannot be made by today’s residual current protective devices. Therefore, unwanted shutdowns by the protective device very often occur without an actual fault. The consequences can be expensive downtimes and restart times as well as production scrap.

With the LEAKCOMP® HP, the operational leakage currents are determined by measuring technology and compensated for in a complex and patented process for residual current circuit breaker.

A precise distinction is made between leakage and fault currents. The AC/DC sensitive RCD regains its clear tripping threshold.

Actual fault currents (due to human contact or insulation faults) are not compensated!

In the current version, up to 500 mA (RMS) can be compensated. The LEAKCOMP® HP is the perfect addition to the RCCB of type B or B+ (e.g. EPA RCCB series) and enables it to be used reliably. Its housing shape (5 division units wide) and the possibility of DIN rail mounting make it easy to use.

So easy!

The LEAKCOMP® HP can be placed directly next to the RCCB or inside the machine. The outgoing mains phases (L1, L2, L3) and the neutral conductor (N) connected to the RCCB are simply routed with flexible cables through the transducer in the middle of the LEAKCOMP® HP. A separate 24 V AC/DC mains supply feeds the electronics of the LEAKCOMP® HP. The COMP terminal of the LEAKCOMP® HP is connected to the protective conductor. Done!

A green LED on the front indicates an intact mains supply. The LCD display shows the leakage current and optionally the result of leakage current and compensation.

You can see how easy the wiring of the LEAKCOMP® HP is in the following videos:

The cabling