Dimmer Doubling/120 volt devices (ETC/Sensor)

[dukeofmuffins]

Lets say we have an auditorium where all accessible dimmer circuits are Dimmer Doubled (ie 77v). If you wanted to say, use a 120v fixture or special lighting effect how would it be done? Besides rewiring the rack/adding a seperate dimmer.

My understanding is that the AC wave is split at the dimmer, giving 77v to one channel and 77v to another. If you were to join two channels with say a twofer adapter, then plug your device into that (think y adapter in reverse), would the device then see both sides of the wave form, hence 120v? I guess its late and the physics are eluding me, but I've always wondered. Or do the dimmers (sensor rack/etc) have some form of protection to prevent this? This is assuming both channels are raised and lowered simultaneously, and that you find two channels on opposite sides of the wave.

This is purely theory, I have never done this and wouldnt even try it without a major bit of research. I just know the auditorium I work in, everything except the work lights and strips are doubled.

And I know this solution or any other probably wouldn't be ETC endorsed, I want to hear your thoughts even if they are the unofficial approach.

 

[Footer]

You can just remove the dimmer doubler and use the dimmer straight. It will require you to go to the rack or the console and set that dimmer to standard dimming, non-doubled. You can not use a twofer to get 120v out of the dimmer. Dimmer doubling mode actually sets the dimmers to their peak, outputing more then 120v.

 

[MNicolai]

Dimmer doublers are remote devices, plugged into the 120v circuit and spitting out two opposing halves of the AC waveform. No modification of the dimmer rack is required to use or cease use of those devices.

If you wanted to use a 120v lamp, you would unplug the dimmer doubler from the 120v dimmer circuit and plug the fixture in directly to the 120v coming from the dimmer rack. In exchange, that gives you control of one circuit where you earlier had two.

The only adjustment that need be made to the dimmer rack is through the facepanel of the control module is to disable dimmer doubling for that dimmer. That can also be done through the Sensor+ Connect web interface for racks with CEM+ control modules, which allows users to login to the control module through Internet Explorer to view and modify rack settings.

 

[rochem]

Dimmer doubling mode actually sets the dimmers to their peak, outputing more then 120v.

Are you sure about this? I don't have a huge amount of experience with dimmer doubling, but I thought the only change when you set it at the rack is how the control data goes to the dimmer, and that the dimmer is still outputting 120V RMS. Because it's alternating current, how could the RMS voltage go above 120V if the peak voltage stays at ~169VAC?

Dimmer doublers are remote devices, plugged into the 120v circuit and spitting out two opposing halves of the AC waveform. No modification of the dimmer rack is required to use or cease use of those devices.

If you wanted to use a 120v lamp, you would unplug the dimmer doubler from the 120v dimmer circuit and plug the fixture in directly to the 120v coming from the dimmer rack. In exchange, that gives you control of one circuit where you earlier had two.

Normally true, I get the impression from reading his post that he's in a house where dimmer doublers are permanently wired into the system somewhere and not simply plugged in to the end of a 120V line. So presumably, the dimmer doublers are buried somewhere in the install and he doesn't have easy access to them. I've never seen or even heard of an installed dimmer doubling solution, and I'm not even sure such a thing exists, but this is what it sounded like to me.

 

[MNicolai]

Normally true, I get the impression from reading his post that he's in a house where dimmer doublers are permanently wired into the system somewhere and not simply plugged in to the end of a 120V line. So presumably, the dimmer doublers are buried somewhere in the install and he doesn't have easy access to them. I've never seen or even heard of an installed dimmer doubling solution, and I'm not even sure such a thing exists, but this is what it sounded like to me.

I received the same impression, but like you, I've never seen or heard of an install with permanently wired dimmer doublers. If that is the case, the doublers should exist somewhere (possibly in the dimmer room but not within the dimmer rack itself) accessible where they can be removed from the circuit and the hot wires leaving one of them can be reconnected to the 120v that was going into the doubler from the dimmer rack.

I'd be a little surprised if the doublers were not at the lighting position locations though -- I don't even know anyone who manufacturers (ETC or otherwise) dimmer doublers in a rackmount form, so all I can imagine is that there would be a room somewhere with a mess of doublers in a patch bay).

 

[derekleffew]

1. ETC is the only company using dimmer doubler technology.
2. Putting the dimmer doublers anywhere other than at the fixtures would require twice as much installed wire and labor, thus negating the savings on the dimmers.

OP, as everyone else has said,
a) unplug the DimmerDoubler,
b) on the CEM set the dimmer to normal, non-doubled, and
c) plug in your 120V conventional fixture.
d) At the console, you can unpatch the (B-side or 256+1) half dimmer, or just leave it be as there won't be anything to listen to it.

 

[dramatech]

Is it possible, that during installation, the male connector of the dimmer doubler was removed, and wired directly to a juction box. This would make it appear as though the the two outputs of the dimmer doubler were two seperate circuits coming from the rack. This install might have been done this way assuming that the folks operating the system, might not really understand how to properly install and remove the doublers as required, such as a high school, where the operators change every few years. This would protect the system from requiring different lamp voltages, while giving a maximum of circuits to work with.

I received the same impression, but like you, I've never seen or heard of an install with permanently wired dimmer doublers. If that is the case, the doublers should exist somewhere (possibly in the dimmer room but not within the dimmer rack itself) accessible where they can be removed from the circuit and the hot wires leaving one of them can be reconnected to the 120v that was going into the doubler from the dimmer rack.

I'd be a little surprised if the doublers were not at the lighting position locations though -- I don't even know anyone who manufacturers (ETC or otherwise) dimmer doublers in a rackmount form, so all I can imagine is that there would be a room somewhere with a mess of doublers in a patch bay).

 

[JD]

Regarding the "over-voltage." ETC dimmers are designed to regulate their output should the line voltage go over 120 volts. Examples:
In / Out
127 / 120
120 / 120
115 / 115

(perfect world where dimmers would be 100% efficient)

They do this by dimming back a bit if the voltage is over 120 volts. They do not however have any ability to add voltage at the full setting. If your line voltage is below 120 volts, your output will be below 120 volts at full.

The result is that if the line voltage were to increase, you would not see any effect on stage. The same is not true if you have a large sag.

As line voltage often is around 125 volts, this supplies a nice cushion of regulation. I believe this can also be set up to regulate output at 115 volts, but I may stand corrected on this.

As we all know, "Normal Line Voltage" is whatever the power company feels like giving you and varies quite a bit from location to location.

 

[farmerjo1111]

In case anyone is wondering. There are a few installations out there that have permanently mounted boxes with integrated Dimmer Doubler in them. ETC has made boxes and strips with the dimmer doubler mounted and hardwired to them. For some spaces it is the best option.

 

[dukeofmuffins]

WOW! Thanks for all the responses guys. I just got out of work to read these.

The system I currently work with is a high school auditorium. The tech support department has been cut back so far that they've been paying me and other alumni to come back and handle lights and sound for the shows.

This is really just curiosity for me. The other day I realized that all of our lamps are 77v, which led me to a "wtf have I been doing all those years" moment. Then I read about dimmer doublers. Then I checked the patch settings. Sure enough, doublers everywhere.

For 42nd Street (many a year ago) I had a bunch of Broadway-esque signs made out of masonite and lots of christmas lights, as well as lit staircases with rope light. In my high-school naivety I thought that the lights were 120v, so I could just wire up a stage-pin plug and presto! While everything worked out well enough, I'm rather sad to realize I wasn't using the full brightness of my signs and other special effects.

I also can't imagine the doublers being located in the racks, since they are all the way down in the green room, and bolted to the brick wall. We do have the black pigtail boxes from ETC running along the catwalk, and on the ends of all the fly pipes with lights. Could the doublers have been built into those as previously mentioned? If so, for future reference, would it be as simple as removing the cover to one of those boxes and disconnecting the doubler? Assuming they aren't hardwired. I honestly can't picture anywhere else they could be located.

 

[Footer]

In case anyone is wondering. There are a few installations out there that have permanently mounted boxes with integrated Dimmer Doubler in them. ETC has made boxes and strips with the dimmer doubler mounted and hardwired to them. For some spaces it is the best option.

Wow. That makes me sick to even think about that ETC would even consider doing that. Having a lighting system that was locked down to only etc units is pretty much the most unusable system possible. Dimmer doubling works great in a touring system. It is also great for adding a few circuits in an installed system. The idea of it being hard wired into raceways is just unfathomable. It amazes me ETC would even consider doing that.

...... Something involving tapatalk.......

 

[theatrelighting]

Has anybody ever come across any other dimmer doubler? ETC's requirements are extremely limiting! I have always been a fan of ETC's equipment, but some of this sounds ridiculous. It seems that there are a ton of permanently installed Strand racks out there that could really use some doubling...

 

[derekleffew]

...ETC's requirements are extremely limiting! ... but some of this sounds ridiculous. ... some doubling...

Help me understand this: so you're mad at ETC because neither Strand nor anyone else has been able to copy their dimmer doubler technology (see U.S. Patent number 5323088)? What's "extremely limiting"? The 77V lamp? I'm sure if someone made a 77V GLA or BTN or FEL, it would work fine.



Sent from my iPhone using Tapatalk

 

[JD]

The dimmer doubling splitter boxes are simply two diodes so the two fixtures only see one side of the waveform each. If you would plug the module into a regular wall outlet or an non-doubled dimmer, both fixtures would come to full, but that's about it. Each fixture would see 1/2 of the waveform. The split duration works out to an equivalent of about a 77 volt RMS waveform. No real magic, but a real cool idea that works well! (Just don't plug the fixtures directly into anything!)

The real heart of the system is the firing circuit that allows the two SCRs inside the SSR to be fired independent of each other.

As far as I know, ETC has the wrap on that.

 

[SteveB]

I share somewhat, Kyle's concerns at having the DD two-fer built into the raceway, as it severely limits (pretty much prohibits the use of and) the flexibility of the system to use fixtures other then those accepting 77v lamps.

That said, I think the fault lies with the consultant and/or architect that allowed this in the first place. For all we know there was a Project Manager at ETC who has a 'puter hard disk full of e-mails stating that it's not the best idea in most instances. At some point the manufacturer is going to build what the consultant spec's, or lose the project, as well as potentially future projects down the road. That's probably not good business practice and in truth has anybody ever heard of permanent DD systems prior to this ?. I never knew it was an option, not that I'd go that route anyway.

I am also not a fan of DD in permanent facilities in general, feeling that the need to keep track of A and B sides to a dimmer when patching, dealing with visiting consoles, etc... make them a pain to deal with.

 

[STEVETERRY]

I received the same impression, but like you, I've never seen or heard of an install with permanently wired dimmer doublers. If that is the case, the doublers should exist somewhere (possibly in the dimmer room but not within the dimmer rack itself) accessible where they can be removed from the circuit and the hot wires leaving one of them can be reconnected to the 120v that was going into the doubler from the dimmer rack.

I'd be a little surprised if the doublers were not at the lighting position locations though -- I don't even know anyone who manufacturers (ETC or otherwise) dimmer doublers in a rackmount form, so all I can imagine is that there would be a room somewhere with a mess of doublers in a patch bay).

There are no permanently installed dimer doublers--only cord-connected.

ST

 

[Footer]

There are no permanently installed dimer doublers--only cord-connected.

ST

Thanks Steve!


...... Something involving tapatalk.......

 

[theatrelighting]

Help me understand this: so you're mad at ETC because neither Strand nor anyone else has been able to copy their dimmer doubler technology (see U.S. Patent number 5323088)? What's "extremely limiting"? The 77V lamp? I'm sure if someone made a 77V GLA or BTN or FEL, it would work fine.

I'm sorry... I'm really not mad at ETC, I think I'm just frustrated that I can't use it in my application. Kudos to ETC!

 

[dukeofmuffins]

Well I suppose I'll do some poking around. I know the bulbs are 77v, the board says Dimmer Doubling is enabled on both racks, and I know we don't have enough dimmer for all of the channels. So by logic, there are dimmer doublers SOMEWHERE in the installation. Going to double check the patch settings and see if perhaps certain floor pockets are still 120. The striplights are old too, so I would think those are 120, and the doublers must have been left off those.

 

[techno89]

Is there a reason you can't just go on a ladder or lift and look for one? Wouldn't that clear everything up? They would only be attached to the Source Fours