PM630 PM632 PM633 ABB DCS system controller processor module

Product Details

Product Description

Product Description
PM630 PM632 PM633 ABB DCS system controller processor module
PM630 PM632 PM633 ABB DCS system controller processor module
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The back-up protection is an “over-current coordination of two over-current
protective devices in series where the protective device, generally but not
necessarily on the supply side, effects the over-current protection with or without
the assistance of the other protective device and prevents any excessive stress
on the latter” (IEC 60947-1, def. 2.5.24).
Besides, IEC 60364-4-43, § 434.5.1 states: “… A lower breaking capacity is
admitted if another protective device having the necessary breaking capacity is
installed on the supply side. In that case, characteristics of the devices, must
be co-ordinated so that the energy let through by these two devices does not
exceed that which can be withstood without damage by the device on the load
side and the conductors protected by these devices.”
The switch disconnectors derive from the corresponding circuit-breakers, of
which they keep the overall dimensions, the fixing systems and the possibility
of mounting all the accessories provided for the basic versions. They are devices
which can make, carry and break currents under normal service conditions of
the circuit.
They can also be used as general circuit-breakers in sub-switchboards, as
bus-ties, or to isolate installation parts, such as lines, busbars or groups of
loads.
Once the contacts have opened, these switches guarantee isolation thanks to
their contacts, which are at the suitable distance to prevent an arc from striking
in compliance with the prescriptions of the standards regarding aptitude to
isolation