recoil system for power supply to moveable truss

[pmolsonmus]

Hi,
I tried a search but didn't find what I was looking for. I apologize if there's a great thread re: this that I've missed - there were some similar but I didn't find what I was looking for. (Why am I hearing Bono's voice right now?)
We just installed 2 motorized trusses into a gym converted to a black box space at the high school I teach in. We're still working out the details, but all is up and operational but we're trying to iron out a few kinks.
The power feeds for the dimmer outlets that are hard wired in the trusses have enough slack in them to allow them to descend to the floor and attach fixtures and make adjustments.
The problem... When the truss is trimmed to its full height, the power line dips about 10 ft below the truss and is very visible. Is there a recoil system similar to a trouble light/ mechanic's suspended extension cord that could keep the slack above the truss and allow it to lower to the ground and recoil without putting stress on the cable? My thinking is that it would have to have some tension, but release when the truss is lowered and recoil when raised. Is there such an animal?

Thanks in advance
Phil

 

[Footer]

Yes, there is. However, they are freakishly expensive. Because they have to have multiple brushes inside they tend to be high priced. If you want to go that way... these guys can do it for you: Conductix-Wampfler

What I would suggest is going with a more traditional cable management system. If you are on chain hoists you could loom the cable on the chain using these: Sapsis Rigging Inc.: 5/16" Chain Runner - Silver

You could also drop the cable into a basket on the truss: Wire Baskets - Industrial Grade Custom Wire Mesh Baskets. It will take a bit of training of the cable, but it is an option.

One other option is to do a cable pick with either another hoist or a simple rope and pin rail. Really though, this should have been though into the design of the entire truss. If you had this professionally installed, you might want to make a phone call and have them come up with a solid solution.

 

[derekleffew]

...Is there a recoil system similar to a trouble light/ mechanic's suspended extension cord that could keep the slack above the truss and allow it to lower to the ground and recoil without putting stress on the cable? My thinking is that it would have to have some tension, but release when the truss is lowered and recoil when raised. Is there such an animal? ...

There is; see Conductix-Wampfler . But the simplest is to use chain runners. See also the threads http://www.controlbooth.com/forums/lighting-electrics/9524-cable-management.html , http://www.controlbooth.com/forums/lighting-electrics/4980-retractors.html , and http://www.controlbooth.com/forums/...ard-practice-dumber-than-dirt.html#post188375 .

EDIT: Curses. Beaten to the punch by Footer once again!

 

[pmolsonmus]

The chain runner looks to be the best and affordable solution.

Thanks!

 

[mjw56]

I just saw your question and thought of a tool balancer immediately.

Tool Positioner, Retractors, Balancers, Tool Balancer

This is just an example i found. Put this device in place of a pick line with the proper attachment to the cable. There may not be enough travel in it and i would bet they it is waay more expensive than the chain runners but thought i would just throw that out there. Good luck

 

[FatherMurphy]

The spring loaded retractors are also called 'Gleason reels'. I've seen an instance or two where they tended to wrap unevenly, causing binds as the cable moved.

We've built some accordion-style ladders to manage cable on moving trusses, 5' to 10' sections that collapse into a stack on top of the truss. I've also seen the cables taped to chunks of pipe that accordion into baskets on the truss.