the serial ballast of an UVR Laboratories Supertan Model H sunlamp consisted of an open Kanthal coil
UVR Laboratories
Supertan Model H sunlamp
The serial ballast of a discharge tube dissipated a
lot of power in the form of infrared radiation, only to
stabilise the current through the ultraviolet radiator.
The idea to use this energy in favour of the sunlamp
therapy was not surprising therefore.
The ballast then had to be placed in sight and it was
often made of Kanthal, but combinations with
(infrared) incandescent lamps, metal tubulars or dull
radiators also existed. The most important property
of Kanthal was that it could be heated until glowing
under atmospheric conditions without any
vaporisation of the material. In early configurations
the Kanthal wire was wound around a ceramic
bearer or it was just an open coil which was
connected in series with the ultraviolet radiator as
can be seen with the Supertan Sunlamp Model H
sunlamp from UVR Laboratories on display here.