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Modifying a Kliegpac...

Discussion in 'Lighting and Electrics' started by pianoman, Nov 9, 2007.

  1. pianoman

    pianoman Member

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    I haven't posted here in a while, and now I have a very strange question. At the theatre at my university, they used to have a couple different lighting systems that worked together in the theatre. One was an ATD system of some sort, and the other was a Kliegpac. Around 1996 I think they got a new system (ETC Express console and whatnot), but they kept the Kliegpac because they thought they might use it in some other space at some point. Well, that didn't happen, so now it's sitting around, unused, and they don't really want to keep it. It looks to be complete as far as I know; it's got the controller and the dimmer (main) unit. I don't remember if the cable to go from the controller to the dimmer pack is there, but I'm sure I could come up with that. Here's my question:

    Bear in mind, I know nothing about how this thing was hooked up, in terms of voltage, pinout, etc. Would it be possible (though some modification perhaps) to wire the unit so that it could be used with standard 120v current? I doubt that's what it's set up for now, but I could be mistaken. Basically I would use it as my own "mini" unit for the four Kliegl ERS fixtures I got from the same theatre. I realize I probably couldn't use the full dimming capabilites as there wouldn't be ample power, but I only have these four instruments which can only take a maximum 750 watt lamp. I also realize that means I would be drawing 25 amps at full power on every instrument.

    So, my idea then is to modify the Kliegpac such that it could be taken to some location, plugged into two separate circuits (so that it would get a maximum of 30-35 amps allowed), and used to dim at least these four instruments. Is this in any way possible, or am I totally crazy? I do know how to work with electricity (I'm not an electrician, but I have worked on electronics and done wiring, etc.). Basically I'm not looking for the Kliegpac to take, say, a 220 source and break it down into several 120V dimmers, I'm just looking to use it as a portable (heavy) dimmer unit. Any ideas as to whether or not this is possible?

    -Dan
     
  2. JD

    JD Well-Known Member

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    Ok, here is what you have to watch out for: The pack may be designed with a common neutral. If this is the case, it will not work for you. In order to work you need to find out two things;
    1) Does it use a common neutral buss or can the individual channels be isolated from each other?
    2) Is there a separate ramp generator for each channel?

    The second question requires a little explanation. If the unit was only designed to work on one phase, there may be only one low voltage transformer feeding the control circuit in the pack. This would be a problem. The control circuit looks to the ac output waveform of the transformer to find its zero voltage crossing point. It uses this point to time the waveform and chop it correctly. You need this for each phase. Some packs only have one. Some packs have three, and some packs have one for each channel. (One per channel is the best.) If each module is electrically independent, including a separate low voltage transformer, than a qualified technician could modify the pack for you. If there is only one ramp generator with one low voltage transformer, then you are condemned to single phase power even if the channels can be isolated. Problem is that if you plug into two outlets, they may not be on the same phase if the building is wired for three phase power. So what happens? Your light will come on to 33% or 66% with the dimmer control set to zero! As you move the fader up, it will go to 100% then blackout, and the start coming up again, stopping at 33 or 66% at full up!
    Please, Please make sure that whoever does the work for you is qualified. Also, remember that when you modify any equipment in this way, you void its UL rating. That can become a liability issue. Generally, this is never recommended.
     
  3. pianoman

    pianoman Member

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    Thanks for the info.

    I checked around, and found the Kliegpac 9 Manual on the klieglbros.com website here. It seems to imply that the Kliegpac can be run off of 3 phase or single phase power if I understand correctly. I realize that I can't use the full potential of the dimming system using only 20A circuits, but it seems from the looks of this that I could possibly connect it using two separate 20A circuits, though again phase could be an issue (though it does seem that it has separate transformers judging by the way the connections change). However, I am not well versed in how this would work out. Any ideas?

    -Dan
     
  4. pianoman

    pianoman Member

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    Additionally, HERE is the rest of the manual...

    -Dan
     
  5. STEVETERRY

    STEVETERRY Well-Known Member

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    The Kliegpac 9 uses a single neutral terminal. It would require extensive modification to be able to work with two separate 20A 120V feeds. This would have to be done by an expert.
    Please, do not attempt this yourself.
    ST
     
  6. pianoman

    pianoman Member

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    I was thinking that was probably the case. I had never heard of a situation where neutrals would be tied together like that...

    -Dan
     
  7. JD

    JD Well-Known Member

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    We really can't give electrical advice (or advice on rigging, scaffolding, ect) on this forum due to the liability issue. I can at least give you an "idea" of your chance of success when taking the unit to a qualified technician or shop:

    The fact that the owners manual shows that you can reassigned channels to different phase legs is a good sign that each has it's own ramp generator. The fact that there is multiple neutral terminals also is a good sign. Here is the pitfall to watch out for. When you are operating dimmers off of standard wall outlets, the neutrals can have no interconnection! For instance, if channel 1 is on one plug and channel 2 is on another, the neutral for channel 1 needs to return to the same plug as the hot came from. Most dimmers have a buss jumper between the neutral terminals. This produces a fire hazard if you are plugging it in multiple wall outlets. Although each outlet is protected by a 15 or 20 amp circuit breaker, only the "hot" wire is protected. Here's an example of trouble: You happen to plug your channels into two outlets that are on different circuits but on the same phase leg. Unknown to you, there is a defective or dirty plug that interrupts the neutral connection on one of your plugs. Everything seams to work correctly BUT you are unknowingly sending 40 amps back through one 12 gauge wire through one prong on a 20 amp plug!
     
  8. pianoman

    pianoman Member

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    Thanks JD, I certainly understand about not giving direct advice. I do have a question about what you just said though: you say that dimmers have a buss jumper between the neutrals. So that means that in a normal dimming system, the neutral is common to all the circuits no matter what phase they are connected to. That makes sense in a polyphase system from what I understand. What I don't understand is what exactly you mean about the fire hazard. Are you saying that if the neutrals of the dimmers were still connected together and the dimmers were run off separate outlets I could have a fire hazard, or are you saying that BECAUSE they don't have a common neutral there is a fire hazard?

    -Dan
     
  9. JD

    JD Well-Known Member

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    If the neutrals were still connected together and you plugged them in separate outlets, you could have a fire hazard. This is because depending on a lot of factors, more current may find its way home through one path than another. Packs generally come with their neutrals bridged as they get installed into a location that has a main feed where the neutral is gauged sufficiently to handle a worse case load, or have a line cord and connector that can handle the same. When you split a pack up and start running it off wall outlets, you limit your "know" neutral wire gauge to #12 (for 20 amps) or #14 (for 15 amps.) That is what is in the walls of the building. Therefore, each circuit needs to be isolated from the other.

    Another example of a "sneak" danger: You are in a building that has had many additions made. You could end up plugging into two outlets that come off of different service panels! (Worse case scenario I admit.) In this case, if there is a neutral imbalance between the panels, you could have hundreds of amps finding their way from one panel to another through your equipment without even turning on a single light!
     
    Last edited: Nov 10, 2007
  10. avkid

    avkid Not a New User Fight Leukemia

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    It looks like the moral of the story is put in a lighting museum or your garage until you have the knowledge to fix it properly.
    Be aware also that modifying it would obliterate any regulatory approvals(UL,CE, etc..)
     
  11. pianoman

    pianoman Member

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    Yeah, as I said, I'm beginning to think this thing is not quite as feasible as I thought. I was just hoping for a (relatively) simple way I could make a dimming system that I could get for the cost of free, work. DMX is sooo overrated. :rolleyes:

    -Dan
     

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