The design of the triggering circuit 1 of the
overvoltage protection, connected via three poles 4 to the
spark gap of the
overvoltage protection, provided with the first input terminal 2 and the second main terminal 3, whose principle consists that an
auxiliary electrode 7 of the
spark gap 4 is connected in series to the first
varistor 8 and one end of the secondary winding 14 of the
transformer 13, the other end of which is connected to the second main
electrode 6 of the
spark gap 4 and the second input terminal 3, whereas one end of the primary winding 15 of the
transformer 13 is connected in series to the gas
discharge tube 10, the second
varistor 9,
resistor 11 and
capacitor 12, connected to the other end of the primary winding 15 of the
transformer 13, connected to the second input terminal 3, whereas the junction connecting the second
varistor 9 to the
resistor 11 is interconnected with the junction, connecting the first input terminal 2 to the first main
electrode 5 of the spark gap 4. The
advantage of such a design of the triggering circuit 1 of
overvoltage protection resides in the thermosensitive
disconnector 17 coupled with the
thermal coupling 16 to the second varistor 9, is either connected in series to the second varistor 9, or connected to the link of the junction connecting the second varistor 9 to the
resistor 11 and the junction connecting the first input terminal 2 to the first main
electrode 5 of the spark gap 4, or that the thermosensitive
disconnector 17 is connected between the primary winding 15 of the transformer 13 and the gas
discharge tube 10.