I don't know about thermostats, but GE dryers from 1957 on that were wired to operate on 120 volts operated at such low temperatures that a plate with a little rectangular opening was made to be inserted in the lint filter opening to give satisfactory wash'nwear performance by restricting the air flow enough to permit temps to rise to around 160F after the fabrics were dry. GE dryers of the modern high speed design from 1957 on that offered a "Low" heat setting did it by operating the heat on 120 volts to keep temperatures low and never reached the operating temperature achieved when the dryer was operated on 240 volts and cycled the heat.
