Dimmer Laws

[Joe Swan]

Just a question regarding setting dimmer channel to switch instead of dim. Obviously this is for control of gobo rotator, KK wheel, mirror ball etc... but can I switch any fixed mains appliance (within the 10A channel limit) eg standard fluorescent tube (UV) or metal halide fixture?

[sparkyweb]

You should not really use a dimmer for switching. - You would be much better off installing non dim circuits.

 

See this link below:

 

Link here

 

And a specific part of the post here:

 

however as many others have said, you never put moving lights, smoke machines, or other 'non-lantern' appliances on a dimmer. Wether it is set to nondim or not. The power is still passing through the triac in the dimmer, so it is not a true sine wave.

 

Hope that helps.

 

mark

 

Edit for more detail---

 

Over time the dimmer or the piece of equipment can be damaged, especially transformers etc.

There are many on this forum who will be able to give you the pure scientific reasons, (Its been a lonmg time since I was at college, I think it has to so with inductive loads, squared off sine waves etc. - but please don't quote me!!)

[Joe Swan]

Thanks, I will run extra circuits to rig for fixed mains appliances.

Good to plan this now as rig will be moterized truss so mains distribution needs to be planned in advance.

[Tomo]

Depending on the dimmers, it may work, but it may not.

 

Discharge lamps hate dimmers of all kinds (except sinewave, but you probably don't have those)

 

Florries are much less sensitive.

 

I wouldn't have any qualms about using an ETC or Zero88 dimmer in switched mode for a florrie, but I wouldn't do it for a metal halide or other discharge lamp.

 

I'd never trust switched mode in a cheap Terralec / Showtec / whatever.

 

Incidentally, which dimmers are you intending to install, and will you have a hard patch panel?

 

If the dimmers are modular with relay modules available (eg ETC Sensor, various Strand) then it doesn't matter about the extra lines as you can just install a relay module instead of a dimming module in the places that require it - although I believe most of these turn two or four channels into relays rather than just one.

 

Equally, if you have a hard patch panel you can easily jump the lines that need hard power to a separate hard power distro.

 

My personal preferred solution is to fit a hard patch panel as it gives you the most flexibility, because you can patch any individual channel into hard power without affecting any others.

[Joe Swan]

Plan on using Betapack 3, Two on each 16m section of motorized quad truss. this puts the dimmers next to fixtures minimizing long multicore so just power and DMX run to each section of rig.

For H & S reasons in this new auditorium the architects are not giving us access to any heights so the rig has to come down to us, ( nightmare focussing!). Any views on new betapack3 for this purpose would be gratefully received. Also deciding as it is a new installation 15A or 16A?

[gingertom]

I feel we need a little more info. before we can stipulate that Beta3s are the problem solver here. How many medium/large scale jobs have we all worked on where there might be be 72/120/ etc ways of dimming, and a huge amount of non-dim distro?

 

I have very rarely seen localised/distributed dimming used on anything other than new installs. That is not to say that it's wrong, of course. But certainly when I do production LX jobs I feel very uncomfortable about having my distro and dimming out of arms reach.

 

HTH

[ben.suffolk]

Check out the post on Distributed Dimming that cropped up some while back.

 

Ben