1873 The arst sewing machine
lampholder was patented by Ludwig M Wolf.
He said this caused the fuse
lampholder to greatly exceed the required temperature, making the lights unsafe.
In effect, the new UL standard 153 for portable luminaires requires additional flammability testing for torchieres that have more than two bulbs in the
lampholder or can accommodate more than 150 watts.
1873: The first sewing machine
lampholder was patented by Ludwig M Wolf.
However, the process took over 10 years, and by the time the requirements were published, the lamp's use had waned due to ballast, igniter and
lampholder issues noticed in the field.
Two basic types of retrofit devices exist: the first is a self-ballasted or integral power supply lamp that has a lamp screw-base or two-pin base to replace an existing incandescent lamp; the second is a component kit that is used to replace the
lampholder, wiring, ballast and/or optics of a luminaire in the field.
These direct plug-in lamps are easy to install into existing
lampholders, requiring no electrical rewiring and no need to change the ballast.