Shock-hazard Protection

Leakage current

Leakage current via the PE conductor results from the combination of equipment and cable leakage currents. The leakage current frequency pattern includes a number of frequencies, whereby the residual-current circuit breakers definitively evaluate the 50/60 Hz current. For this reason, the leakage current cannot be measured using a conventional multimeter. Contact our application department for help to calculate the leakage current in your application.

Since the leakage current to PE is more than 3.5mA, in compliance with IEC 61800-5-1 the PE connection must either be doubled or a connecting cable with a cross-section >10mm² must be used. Use the PE terminal and the PE connection screws in order to fulfill this requirement.

Use the following measures to minimize leakage currents:

Residual current protective device (RCD)

In conformity with IEC 60364-4-41 – Regulations for installation and IEC 60204 – Electrical equipment of machinery, residual current protective devices (RCDs) can be used, provided they comply with the requisite regulations. The servo drive is a 3-phase system with a B6 bridge. Use RCDs which are sensitive to all currents in order to detect any DC fault current.

Rated residual currents in the RCDs:

10 to 30 mA

Protection against "indirect contact" (personal fire protection) for stationary and mobile equipment, as well as for "direct contact".

30 to 50 mA

Protection against "indirect contact" (personal fire protection) for stationary equipment

Isolating transformers

The servo drive can be operated with an isolating transformer. A ground-leakage monitor may also be used to detect short circuits. This will provide protection against indirect contact despite a higher leakage current, or when an alternative form of shock-hazard protection is needed.

The length of wiring between the transformer and the servo drive should be as short as possible.