[SML] Chain Motor Help...

[Alex French]

On Fri, Mar 4, 2016 at 5:06 PM, Brian Munroe via Stagecraft <
stagecraft at theatrical.net> wrote:

> All that said, if you want to use chain motors to lift people, be sure
> that is an approved use by the manufacturer.  Also, using multiple motors
> (more than 2) puts in in to "indeterminate" load calculations for load on
> each point. Very difficult to calculate loads at that point without the use
> of load cells.
>

>2 picks = statically indeterminate is only true if we're talking about
something linear, a batten or truss.

If the 3 pick points define a plane (they're not in a straight line), that
is statically determinate.  It would take a 4th pick to be statically
indeterminate.

A 3-legged table can never be wobbly, all 3 legs are engaged (and forces
have to be very close to equal if things are symmetrical and level-ish).  A
4-legged table that wobbles depending on which diner is cutting their food
is sort of a magnified example of being statically indeterminate.

Alex French
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