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BETA Switching
Timers
7
LF6, 5TT1 3 timers for buildings
9/20
Siemens ET B1 · 10/2008
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More information
Stairwell lighting
This is required in DIN 18015-2 "Electrical systems in residential
buildings; minimum type and scope of the equipment". What is
less known is that 100 lux is required according to EN 12464-1
"
Lighting of workplaces" for traffic areas and corridors, section
5.3.
This means that approx. 60 W incandescent lamps, 25 W
energy-saving lamps or 25 W fluorescent lamps need to be
used. It is hard to see why lesser requirements should apply to
stairwells in residential buildings than stipulated in EN 12464-1.
4-
wire circuit, L-momentary contact
4
conductors are installed within the building. The timing interval
is started by pressing phase L. During the runtime, the timer can
be reset at all times.
3-
wire circuit, L-momentary contact
3
conductors are installed within the building. The timing interval
is started by pressing phase L. No resetting is possible during
the runtime as the pushbutton input and output are exposed to
the same potential during this period. The glow lamps are
switched off during the runtime.
3-
wire circuit, N-momentary contact
3
conductors are installed within the building. The timing interval
is started by pressing the N-conductor. During the runtime, the
timer can be reset at all times. However, this switching no longer
corresponds to DIN VDE 0100 and is now only used in old
installations.
Safety through warning prior to switch-off
DIN 18015-2 "Electrical systems in residential buildings: type
and scope of minimum equipment" stipulates that the automatic
lighting-off control in stairwells of multifunctional dwellings must
be equipped with a warning function to prevent sudden darkness
in the building. This contribution towards safety is offered by
4
device versions. The 7LF6 113 stairwell lighting timer, the
7
LF6 114 lighting timer and the 7LF6 115 energy-saving timer
warn of an impending off by flashing, the 5TT1 303 stairwell lighting
timer ECG warns of the impending switch-off by dimming, allowing
sufficient time for the light switch to be pressed again.
Manual switches
All timers have a manual switch for the function Automatic/ON.
This allows the operator to switch to continuous light in the event
of moving house or emergencies.
Useful continuous contact
Pushbuttons should never jam. For this reason, all our timers
have a safeguard to prevent this type of malfunction. Even
better, this feature can be used (e.g. by caretakers of properties)
to switch to a continuous light in the event of moving house or
emergencies.
Setting accuracy
The electronic remote control switches offer a high degree of
accuracy. The runtime can be set precisely to + 30 seconds
using the push-to-lock knurling wheel setting. The factory
settings ensure that the limit values of 1 and 10 or 60 minutes
can be reliably set.
Short-circuit strength
Stairwell lighting timers are primarily used for the switching of
incandescent lamps, which may occasionally be subject to short
circuits.
A key feature of all devices is their high short-circuit strength
without the contacts welding.
Switching of fluorescent lamps
In order to extend their service life as far as possible, fluorescent
lamps should only be switched using a stairwell lighting timer if
the switching frequency is not excessive. Using electronic
ballast (ECG) to operate them is more gentle on the device and
saves energy. The 5TT1 303 stairwell lighting timer ECG switches
the electronic ballast and warns of the impending switch-off by
dimming.
Switching of energy-saving lamps
The switching of energy-saving lamps has provoked heated
discussions. Energy-saving lamps require a certain time before
they produce their full light output. The characteristic of the
electronics is not ideal for flashing operation. They do not dim.
It is difficult to find suppliers of energy-saving lamps that are
suitable for stairwell lighting timers and comply with the required
specifications.
© Siemens AG 2008