Westinghouse, Weston, GE and Queen & Company meters from 1886 until the 20th century. See closeups of construction. These meters were used as part of the Universe of Instrumentation program. Edward Weston developed the PMMC (permanent magnet moving coil) in 1886 and this led to many advancements in meters. With Weston, Thomson, Shallenberger and others AC power systems would have trouble advancing as measurement is extremely important for innovation.