Equalizer bar

[NE12345]

I am currently working on a retrofurb of a crane and the customer wants an equalizer bar assembly and the only place to place it without losing hook height is over the upper nest and using the equalizer sheave to reroute the ropes as shown in the attached drawing. Now the purpose of the equalizer is when the rope lengths are different the equalizer compensates and turns balancing the load now what the customer wants is calculations on the rope load when the equalizer is at the maxed out position. From what I can see the vertical force of the rope load will be the same no matter what but when I calculate the moments, when the equalizer bar is at the maximum position I have a resultant moment, I am missing something or making bad assumptions, any help would be appreciated. Thanks.

 

[BUGGAR]

What are you using for your moment arm distances and directions to the cable forces? As you note, the cable forces and resulting moments must be equal or your equalizer will rotate. Forces have to align with the cables and the moment arms have to be at right angles to the cable and pass through the rotation point of the equalizer. The legs of equalizer have to be equal also.