Siemens SIRIUS 3RT Series System Manual page 767

5. Cover for the power supply terminals to protect against accidental contact
6. The switching capacity must correspond to AC-23 for motor switches and AC-22 for load-
break switches (utilization category).
7. Switch position displayed automatically
Mirror contacts of power contactors
A mirror contact is an NC contact, which cannot be closed at the same time as an NO main
contact (according to EN 60947-5-1, Annex F).
Modular system
The SIRIUS modular system offers all the functions and devices needed for switching,
starting, protecting, and monitoring motors and systems. In other words, it provides a
modular range of standard components, which are perfectly matched to one another, can be
combined really easily, and use the same accessories.
Motor protection
Protection for three-phase motors against overload and short circuit, i.e. protection for the
winding insulation against impermissible heating.
Motor starter protector
Generally a latch-operated switch, which can switch on, conduct, and switch off currents in
the circuit under normal operating conditions; it can also switch on the current up to the point
of a short circuit under specified operating conditions that are not normal, conduct current for
a defined period, and interrupt it too.
n release
Short designation for "instantaneous electromagnetic overcurrent release".
OFF-delay
The time interval effected by a timing relay or timer (on contactors, for example) between a
switch-off command being issued and the contacts of the timing relay or timer reaching their
initial position.
ON time in %
The duty ratio ON time in % is the ratio between the load duration and the cycle duration for
loads that are frequently switched on and off.
Operating range
Range within which the operating voltage of a contactor may deviate from the rated
operating voltage without impairing the operational reliability of the switching device (e.g.
contactor drop-out).
SIRIUS Innovations
System Manual, 01/2011, A8E56203870002-03
Glossary
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