Excitron

A Excitron (also Exzitron or Exzitronröhre ) is a mercury vapor rectifier with only one anode (Einanoden rectifiers ). Since with only one anode ignition is necessary for each period , an arc is permanently maintained by means of an auxiliary electrode directly above the mercury surface. This auxiliary electrode is called the exciter anode. excitation anode , from which the name of this type of rectifier is derived.

The advantages of the Excitron compared to the multi-anode rectifier, the usual design of a mercury vapor rectifier with several anodes, consists in:

• lower by about 20% arc - voltage drop and associated increase in efficiency . This is possible because the anode is spatially closer to the cathode .

• a higher current carrying capacity of 3000 A upwards. The higher currents are possible because with this rectifier there is no risk of flashback between two or more anodes as with the multi-anode rectifier. For this reason, this type of rectifier was mainly used with high current loads such as in aluminum electrolysis.

A corresponding number of single-anode rectifier vessels is necessary for use as rectifiers in three-phase or multi-phase networks. In addition, reserve maintenance is simplified, since if a rectifier fails on one phase, the entire rectifier system does not have to be replaced.

Excitrons were used as power rectifiers in industry until the 1960s. Today they have been almost completely replaced by thyristors and IGBTs .

literature

• Dieter Anke: Power electronics . 2nd Edition. Oldenbourg, 2000, ISBN 978-3-486-22634-8 .