What is that for?

[LPdan]

Just curious - often when I see photos of large old lighting control panels (Frankenstein type), there is what looks like a single steering wheel on the panel. Guessing it is not an encoder. Any idea what function it served?

 

[almorton]

My old school had a "ship's wheel" on the rheostat that controlled the houselights.

 

[sk8rsdad]

It's usually the master, geared with a mechanical advantage to move all the other levers.

 

[LPdan]

Makes sense, thanks!

 

[RonHebbard]

Just curious - often when I see photos of large old lighting control panels (Frankenstein type), there is what looks like a single steering wheel on the panel. Guessing it is not an encoder. Any idea what function it served?

@LPdan In my experience, these types of dimmer boards were auto transformers, rather than heat generating / power wasting rheostats.
Typically there were several (3 or 4 horizontal rows) Each handle could be rotated 90 degrees to lock it to (or unlock it from) its horizontal mastering shaft.

The first handle on the left end of each row was usually a different colour (Black); rotating the black handle would similarly lock its horizontal row to a Grand Master, mastering the entire panel.

Operating the Grand Master required serious effort with various techniques being used to provide appreciable mechanical advantage.
Sometimes the Grand Master was a long handle ~3 feet; the long handle was a trip hazard.
Long handled Grand Masters often extended ~12" from the board and were bent 90 degrees up so they stood vertical / parallel to the panel when at 100% and horizontal (or slightly lower) when at 0%.

The "Single steering wheel" you described was often the mechanical grand master.
Rotating the wheel rotated a worm gear and employed the self-locking / high mechanical advantage of the worm gear to mechanically muster (and Master) the entire panel without protruding appreciably from the panel.

Toodleoo!
Ron Hebbard

 

[RonHebbard]

@LPdan Further to my previous novel: The mastering shaft traversing the full length (width) of each horizontal row had a continuous, full length, key way milled into it. Individual dimmers at 100% could be pre-rotated and locked.
Dimmers set less than full could be rotated and preset to lock as their mastering shaft rotated, thus collecting / coralling them as it rotated past.

Similarly, Master handles for the horizontal rows could be locked and would likewise be captured by the Grand Master on its way to lower levels.
Sub mastering, or Grand Mastering, on the way up required more skill, practice, prayer and luck to individually unlock sub masters &/or individual dimmers on the way back up.

Skilled operators perfected various moves and choreographed dance routines involving wrists, forearms, elbows, ankles and knees.
When forearms were insufficient; four arms were added resulting in carefully rehearsed duets and trios involving wondrous (humorous) contortions which would definitely violate polite / social distancing conventions.
Toodleoo!
Ron (Who, unfortunately, became too well acquainted with the sweaty BO of his seniors) Hebbard

 

[JonCarter]

Been there,done that, and had a few bruises to prove it.

 

[Jay Ashworth]

[ Annoyed mutter about the Ion XE dropping grandmaster faders goes here ]

 

[JohnD]

If anyone wants pictures, click through some of the Bob Foreman posts in this section.

 

[sk8rsdad]

[ Annoyed mutter about the Ion XE dropping grandmaster faders goes here ]

Any fader, or all of them can be mapped to a grandmaster, just like Ion's bigger siblings.

 

[n1ist]

I remember working a piano board where the grand master was a broomstick. Lay it across all the handles and pull down...
/mike

 

[RonHebbard]

I remember working a piano board where the grand master was a broomstick. Lay it across all the handles and pull down...
/mike

@n1ist The majority of the 'Broomstick' mastered piano boards were power wasting / heat generating resistance rheostat boards.
'Broomstick' mastering was far less common with autotransformer piano boards.
Toodleoo!
Ron Hebbard

 

[David Ashton]

in those days I worked a 18 channel Strand resistor board, by the end of the night I was sweat soaked and physically exhausted but we did have 6 high tech Strand colour wheels on F O H to switch over between cues.

 

[RonHebbard]

in those days I worked a 18 channel Strand resistor board, by the end of the night I was sweat soaked and physically exhausted but we did have 6 high tech Strand colour wheels on F O H to switch over between cues.

If it had been in the disco era, you could've been switching during cues.
Toodleoo!
Ron Hebbard