KI front panel "VOLTAGE" adjust?

On Tuesday (08/13/2013 at 08:46AM +0200), Pontus Pihlgren wrote: Interesting pictures. I am curious why machines of this era often have a "VOLTAGE" adjustment on the front panel? Was it really neccessary for an operator to adjust some voltage setting as the machine ran thus requiring that adjustment to be easily accessible on the front panel? What is it about the design that requires this? Why wouldn't the voltage adjustment be on the back or down inside where some knob twiddler can't get to it? It looks like the knob turns a variac so it's adjusting an AC voltage while the meter reads DC... so is it perhaps adjusting the AC mains input to a/the power supply, because the mains voltage wasn't stable? The variac seems a little small for that but ... Curious. -- Chris Elmquist