The output of a squarewave AC power inverter. These are also known as “modified sine wave” in some cases. 50V/div. Vrms = 120.15. Note the naughty ringing on one of the shots, this results from a mixed inductive and resistive load, with the inductive load being a motor on solid state speed control. Needless to say, this ringing may be damaging to some equipment, and a true sine wave inverter should be used on anything particularly sensitive. The tiny pulses are the “search mode”, where the inverter is in power saving operation, looking for the presence of a load that needs power.

Otis gearless elevator machines. These are literally just a giant, low-speed, high torque DC motor. The green motor/generator set appears to be running a service elevator that has not yet been modernized. These were once Otis Autotronic elevators and have been modernized with some quite boring yet efficient and reliable GALaxy controllers.

In a semi-flooded and almost forgotten underground space below Downtown Miami… “SBC Loves You”. 

We always practice safe engineering porn here. All of these telco circuits are using protectors.

A candid shot of the phone wiring at the office.

Hot Motor Commutator Shot.