Closer to 1930 it became very common to convert machines, the price of motor and light dropped and made it more affordable. The practice continued most of the 1950s. The motor was introduced early on with the introduction of electricity, I'm guessing the last decade of the 1800s. According to some info a mains powered Singer could be ordered in 1903. The motor was first fitted to the bed of the machine, but quite early on it was