Dimmer Doubling/120 volt devices (ETC/Sensor)

[Grog12]

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.

I have to agree with SteveB here..this sounds like a descion made outside of the ETC family. Someone thought it was a "smart" way to save and didn't plan for every eventuality.

 

[JD]

If they are in the raceway, that is bad news. The diodes inside produce about one watt of heat for every amp running through them*. With two 750w loads, that comes to 15 watts. No problem out in the open, but sealed in a raceway with no air circulation could cause a problem.

If a diode were to go, it would fail as a short, allowing the full 120 volts to hit the lamp.

Easy way to figure this out. Plug in a 120 volt test light. If you cannot get it to full intensity, then they are in there somewhere.

* 750w 77 volt lamp would draw 9.74 amps, but duration would only be 50% with half-wave.

 

[zmb]

Is it possible that somewhere, the max output is 77v and is keeping the lamps from blowing?

 

[jglodeklights]

Is it possible that somewhere, the max output is 77v and is keeping the lamps from blowing?

Only if the following weren't true:

A. ETC's Dimmer Doubling system is the only system (that I know of) in the world to use dimmed 77 volts. (I know some Middle East hotels use sine wave splitting at 230 volts to increase the efficiency of their system in allowing more lamps to be mounted on it) and as such would require expensive custom electrical installation to create.

B. Enabling Dimmer Doubling on the console and racks (as is stated is probably the case by OP) would result in 33.5 volt sends to units, at best. And only if dimmer doublers were actually installed.

Combined with the fact that there are some non-dimmer doublerable units, that seems unlikely, especially since it wouldn't allow for increasing the number of usable channels.

 

[xander]

There is a lot of information being thrown around in this thread without much knowledge of the real facts of the OP's venue. Before the OP goes off and does something that gets himself or the equipment damaged, maybe we should lay off the theories and speculation. The simplest way to find out whether the system has DD modules somewhere is to open up a S4 cap (making sure it is off and unplugged, first) and checking the lamp. 77v or 115v?


I mean no offense and I'm sure these are just slip ups, but just to make sure no one is getting fed misinformation, here are some minor corrections.

I have only used them once. The venue swapped out the dimmer doubler L5-20's with 2P&G with bright red cap covers. Once an instrument went to 77v, it too had the cover replaced with a bright red one until it was swapped back.

Dimmer doublers come with L5-15 connectors. L5-20 are a common connector used in theaters for line voltages and would therefore not accomplish one of their goals, that of avoiding plugging higher voltage loads into the 77v output.

If they are in the raceway, that is bad news. The diodes inside produce about one watt of heat for every amp running through them*. With two 750w loads, that comes to 15 watts.......

* 750w 77 volt lamp would draw 9.74 amps, but duration would only be 50% with half-wave.

77v HPL lamps for use in a dimmer doubled system are 550w, not 750w.

-Tim

 

[domiii]

77v HPL lamps for use in a dimmer doubled system are 550w, not 750w.

-Tim

They do have 750W/77V lamps. I purchased some from BulbAmerica.

USHIO HPL 750w /77v halogen bulb

 

[xander]

They do have 750W/77V lamps. I purchased some from BulbAmerica.

USHIO HPL 750w /77v halogen bulb

I stand corrected. I had never heard of this lamp until 60 seconds ago. It must be relatively new as it's not on ETC's list of Source4 compatible lamps.

-Tim

 

[nray6905]

I wasnt sure if anyone had really found a probable solution to this yet but i thought i would chime in anyway and i do hope it makes sense.

I would for a profession regional theatre company and i make complete use of the dimmer doubler technology. We only have 250 dimmers but currently have 400+ fixtures in the current working inventory. Now with the 550w 77v lamps they will ONLY work with dimmer doublers, if they are connected to straight (un dimmer doubled) circuit they will blow! Now, that being said, if a dimmer is set for doubling you can still run a 575w or 750w on that circuit with basically "half" the power. But from speaking with ETC, there is no such thing as permanent dimmer doublers.

With the dimmer doublers that i currently use, we have taken all of the 15amp twist locks that come with them off and replaced them with stage pin connectors because there is no reason to have to make up a completely new cable library of twist locks. All you need to do is use E-tape and tape the connectors that have the 77v lamps in them.

You can also with the doublers "two-fer" the A and B sides of the doubler with a totally of 4 77v fixtures, two on each side.


I really hope this helps.

Nathan Ray
Lighting Designer/Technical Director

The Renaissance Center
Nashville, Tn 37055
The Renaissance Center