086388-001 ABB Controller module motor card inventory

Description

A switch disconnector as defined by the standard IEC 60947-3 is a mechanical
switching device which, when in the open position, carries out a disconnecting
function and ensures an isolating distance (distance between contacts) sufficient to guarantee safety. This safety of disconnection must be guaranteed and
verified by the positive operation: the operating lever must always indicate the
actual position of the mobile contacts of the device.
The mechanical switching device must be able to make, carry and break currents
in normal circuit conditions, including any overload currents in normal service,
and to carry, for a specified duration, currents in abnormal circuit conditions,
such as, for example, short-circuit conditions.
Switch disconnectors are often used as:
• main sub-switchboard devices;
• switching and disconnecting devices for lines, busbars or load units;
• bus-tie.
The switch disconnector shall ensure that the whole plant or part of it is not
live, safely disconnecting from any electrical supply. The use of such a switch
disconnector allows, for example, personnel to carry out work on the plant
without risks of electrical nature.
Even if the use of a single pole devices side by side is not forbidden, the
standards recommend the use of multi-pole devices so as to guarantee the
simultaneous isolation of all poles in the circuit.
The specific rated characteristics of switch disconnectors are defined by the
standard IEC 60947-3, as detailed below:
• Icw [kA]: rated short-time withstand current:
is the current that a switch is capable of carrying, without damage, in the
closed position for a specific duration