Shock-Hazard Protection; Leakage Current; Residual Current Protective Device (Rcd); Isolating Transformers - Kollmorgen AKD 2G-S Series Installation Manual

3.5 Shock-hazard Protection

3.5.1 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 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 3.5 mA, in compliance with IEC61800-5-1 the PE connection
must either be doubled or a connecting cable with a cross-section >10 mm² must be used. Use the PE
terminal and the PE connection screws in order to fulfill this requirement.
The following measures can be used to minimize leakage currents:
Reduce the length of the engine cable.
l
Use low capacitance motor cables (➜ # 55).
l

3.5.2 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 the requisite regulations are complied with. The
AKD2G is a 3-phase system with a B6 bridge. Therefore, RCDs which are sensitive to all currents must be used 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".
50 to 30 mA Protection against "indirect contact" (personal fire protection) for stationary equipment
Recommendation: In order to protect against direct contact (with motor cables shorter than 5 m)
Kollmorgen recommends that each drive be protected individually using a 30 mA RCD which is sensitive to
all currents.
If you use a selective RCD, the more intelligent evaluation process will prevent spurious tripping of the RCD.

3.5.3 Isolating transformers

When protection against indirect contact is absolutely essential despite a higher leakage current, or when an
alternative form of shock-hazard protection is sought, the AKD2G can also be operated by using an isolating
transformer. A ground-leakage monitor can be used to monitor for short circuits.
Keep the length of wiring between the transformer and the drive as short as possible.
AKD2G-S Installation Manual, Safety 1
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