Siemens 340 Manual page 166

Glossary
Main switch
Every industrial machine which falls under the scope of DIN EN 60204 Part 1 (VDE 0113,
Part 1) must be equipped with a main switch which disconnects all electrical equipment from
the network while cleaning, maintenance, and repair work is being carried out, as well as
during long periods of downtime. Usually a switch which can be operated by hand is
stipulated in order to prevent electrical or mechanical hazards. The main switch can also
function as an EMERGENCY-OFF device.
It must meet the following requirements:
1. Externally accessible handle.
2. Only one "Off" position and one "On" position with allocated stops.
3. Two positions labeled "0" and "I".
4. Lockable "Off" position.
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.
Motor protection
Motor protection protects electric motors against thermal overload due to mechanical
overload or in the event of failure of a single or two phase(s).
Motor starter protector/circuit breaker
Generally a latch-operated switch that can make, carry, and break currents in the circuit
under normal operating conditions; and that can make current under specified conditions that
are not normal up to the point of a short circuit, conduct the current for a defined period, and
break it.
Operating range
Range within which the control circuit voltage of a switching device may deviate from the
rated control circuit voltage without impairing the operational reliability of the switching
device (e.g. shutdown of the 3RM1 motor starter).
Overload relay
Inverse-time delayed relay which responds to an overload in accordance with a time/current
characteristic, thus protecting the switching device and any load against overloads.
Overload release
Overcurrent release that provides protection against overload.
166
SIRIUS 3RM1 motor starter
Manual, 11/2013, A5E0345285095020A/RS-AB/002