Datasheet

Guide to Starters Page 7 of 17
5 DEOS
®
starters ST 171 / ST 172 / ST 172 SAFETY
5.1 Design
In contrast to the starters in Section 4, the DEOS
®
starter has an NTC resistor (negative temperature
coefficient) and a bimetallic switch.
Figure 3: Circuit diagram for the DEOS
®
SAFETY starter
5.2 Operation
Ignition as described for the starters in Section 4.2.
In addition, fluorescent lamps that are faulty or at the end of their lives are safely and reliably shut down.
5.3 Operating mode
Normal operation is the same as described in Section 4.3.
In addition:
If the lamp can no longer be ignited at the end of its life or if there are repeated ignition attempts (flashing)
the heat that is generated by the NTC (hot conductor) is used to trip the bimetallic switch. This then opens
the circuit.
The lamp should now be replaced.
Press the red button back into the starter casing (disconnect from the power supply first). The starter is
now ready to operate again and can ignite the lamp.
This ability of the starter to shut down lamps that are faulty or are at the end of their lives enhances the
SAFETY, convenience and life of a lighting system.
5.4 Technical data sheets for DEOS
®
starters ST 171, ST 172, ST 173
SAFETY
The technical data sheets are given in section 10.