Some were a double helix with 2 elements. High would be 240/240
medium high 240/120
medium 120/120 or 240/0
medium low 120/0
low 60/60 (series across 120).
@TechConnectify Shorter cycles can get annoying. I have a Winston HC4009 CVAP holding cabinet that cycles the elements at .5Hz. It causes many of the lights in the house to vary ever so slightly in brightness at that rate.