mercury arc rectifier

Noun

mercury arc rectifier (plural mercury arc rectifiers)

1. A rectifier which converts alternating current to direct current, using a cathode tube with a pool of liquid mercury. Now superseded by solid-state rectifiers.
   • The secondary winding is laid in four coils, one on top of the other, with oil passages round the laminated-steel core; its 2,770V a.c. output is converted to 1,970V d.c. by four air-cooled mercury arc rectifiers, which feed each pair of 975V traction motors through a smoothing choke.1961 March, “Interim report on the Glasgow suburban electric train failures”, in Trains Illustrated, page 175
   • Additionally, semi-conductor rectifiers are far more economical of space, with the result that there is room in the Doncaster-built locomotives employing them for rheostatic braking apparatus within the weight and dimensions previously needed for mercury-arc rectifiers.1961 December, “Talking of Trains: The 25kV rolling stock”, in Trains Illustrated, page 708