Home Forums General Discussion Technical Questions Do vacuum tube logic elevator controllers exist?

Most older elevators (c. 1979 or earlier) were built with relay logic controllers.

Many newer elevators (c. 1990 or later) are built with solid state logic controllers.

But were any "vacuum tube logic" elevator controllers made? I have never heard of such a thing, but I am curious if such a controller was ever made. If one was made, I would love to see a photo of it.

Note that I am not an elevator technician, but an elevator enthusiast asking this question out of curiosity.

Otis used rectifer tubes on its touch buttons. They used tubes in other controllers, but there were no vacuum tube controllers. Otis did have an op-amp dispatch controller. Turnbull had a vacuum tube motor control on a wound brake to force a three phase AC motor to slow down to a smooth stop. Tubes have been used in timer circuits and other peripheral equipment.

I'm not exactly sure what you mean by "op-amp dispatch controller"?

I think dispatch controller means the controller used on a bank of multiple elevators that decides which elevator can answer a hall call the fastest.

I assume you are talking about vacuum tube op-amps.

Is the dispatcher mostly relay logic with a few vacuum tube op-amps for specific functions? Or are the vacuum tubes used for most of the dispatcher logic and there are few relays?

yeah and a real mongrel when they played up in humid weather, not to mention the balanced bridge door detector...nasty if the tenite covers got broken..LOL

If you ever have the chance to see the original advertisement for that dispatcher, note that the power switch for the dispatcher is in the OFF position.