OT: I hate lights!

[lifeloverwg]

I've been working on stage lighting for the Social Hall at my Church off and on for the last couple weeks. We have been taking stuff down from the Sanctuary, running multiple extension cords to power it and tearing it down setting it back up for the next service for years whenever we had a production in that space.

We scored a bunch of free used curtain and old lighting fixtures from one of the local large theaters last year and we installed the curtain on the back and side walls for last years service trip fund-raising concert. (already had front curtain)

This year I've been taking on lighting and power for the space. I got new black pipe up, new plugs and cords on the fixtures, new bulbs for said fixtures (we don't really need 750-1000w bulbs for a 20' throw), gel frames and gels, fixtures hung, some used and some cheap new dimmer packs purchase and ordered, DMX cable soldered up and strung and a contractor to run a 100 amp subpanel to the stage and circuits up to the hang points and walls.

OK, so he's a contractor and only has the subpanel in and some temporary outlets hanging off of it in time, I take a deep breath, no big deal. At least I don't have to run extension cords as far this year. Dimmer packs arrive and get hung yesterday. We haul in the band gear and system to setup for the concert, setup goes smoothly, band practices for soundcheck and all's well.

Time to aim and trim lights now that it's dark. Humm, dimmer pack not responding, up ladder, check settings, down ladder try again, back up ladder recheck address and settings, chase works, DMX doesn't, smells funny, loud pop right in front of my face and dimmer goes dark. One used dimmer pack down, that's not good. Down ladder with dimmer in tow. Fuses are fine, what to do?

I decide I don't really need two dimmers for stage wash, so up another ladder, down with pack, back up first ladder, rehang and reprogram and we're up and running.

Let's set a scene.

First pack works now, second pack works fine, third pack not responding properly. Move second ladder, climb up, check settings and address, nothing, DMX signal light is good, my back stage LED fixtures beyond this pack are responding fine so it's not a cable issue. I power down the unit, unplug, replug, shake it, swear at it, one channel works in all settings, other three don't! Brand new out of the $55 box. Funny, it doesn't say Behringer on it....... but it is priced like it so what do I expect? After another hour of headscratching I give up, program one scene with front and back lighting and go home to bed. Can't sleep, thinking about lighting for now tonights performance.

Looks like it's time for another extension cord and a couple of static wash fixtures for another year........

Crossing my fingers and praying to all the Gods that I've stabilized at this 50% failure rate.

Time to head back out so maybe I can get a nap before showtime.

 

I now hate lighting even more. Winston

[agedhorse]

Solidly bond the mounting pipes to safety ground unless bonded to the conduit system. Unlikely if you are using extension cords.

[BillESC]

^^^ Good idea, for your own safety.

[lifeloverwg]

Solidly bond the mounting pipes to safety ground unless bonded to the conduit system. Unlikely if you are using extension cords.

 

Is that a standard double safety measure? All fixtures and power cords are grounded, but I never thought about grounding the pipe. Conduit will of course be grounded once it's in.

 

I did lose one front fixture's bulb 15 minutes before showtime for no apparent reason. There was food and auctions happening in other spaces so I was able to drag out a ladder and quickly stick an old higher wattage bulb back in, but it immediately went out as well on power up so I obviously have some issue. A short n the fixture I assume.....? I did power down before changing out the bulb, so thankfully no shocks when up a ladder.

Show went well, lights looked OK, but with the loss of another fixture and level of control I couldn't do as much scene changing as I now had a hole in the coverage and loss of color with some scenes in addition to the lost dimmer packs. Most people never noticed. We had a smaller crowd than the last two years, but the total funds raised was still pretty close. Had a few local musicians not associated with the Church show up this year to check it out too. It is becoming a nice space that is available to the community and word might be getting out before I'm ready.

 

Winston

[Dogoth]

It sounds like multiple problems. Here's my limited knowledge about lights.

 

Firstly the loud pop was probably the SCR (really a triac) dyeing in the dimmer box. That's the main part of the dimmer so probably it's toast (have a professional look at it - don't take my word as gospel as I said my knowledge is limited).

 

Here's some things to try if your dimmers aren't responding.

 

DMX cable isn't the same as mic cable (is your system 3 pin or 5 pin?). the cable its's self must be rated at a different impedence than 600 ohm mic cable. This is usualy more of a problem when running long lines or daisy chaining multiple dimmers (mic cable will work sometimes, but it's not recommended).

 

DMX wants to be terminated at the last device only (there should be a switch somewhere to terminate the unit (I think it's either 50 or 75 ohms (again don't quote me)). If there is a termination load anywhere other than the last unit in the chain, it can do two things, load the system improperly and cause ringing (which can cause all kinds of goofy errors - including not responding at all). Ringing is a resonance based on the freq of the DMX and the length of the cable (in video it looks looks a ghost or shadow image). I have seen units that didn't have a termination switch, in which case you must get an XLR with a termination resistor in it (I'm not sure across which pins but the info is available on the net).

 

I'm sure that you've checked that you're not overloading any particular dimmer circuit so that's the extent of my knowledge.

 

Hope it helps.

 

FWIW I hate lights too :>)

[Redbassman86]

 

Is that a standard double safety measure? All fixtures and power cords are grounded, but I never thought about grounding the pipe. Conduit will of course be grounded once it's in.

 

 

Gotta bond anything likely to become energized. Def wouldnt take much of a mishap to make a steel pipe with a bunch of 1K PARs hot. Could even become energized through induction depending of how your cables are run. I once saw a bunch of PAR 64s hung on a pipe. They were terminated with stage pin connectors, and all the conductors were individual. The nice man installing it decided all the greens should get wrapped around the pipe together, then the whites, then the blacks. Can you say 97 volts to ground? Magnetic inductance is no joke, I'm sure Agedhorse has some great stories about that stuff with his experience in industrial power systems.

[Mogwix]

I don't know my head from my own ass while working with lights.

 

They do make things pretty though.

[agedhorse]

Bonding the grid is a good safety measure, if it's attached to building steel that's already bonded to system ground then it's not necessary but the reason is to insure that the pip stays at ground potential regardless of what's brought in or what's happening around it. If you are up on a ladder and happen to grab building steel and the pipe, you want to be damn sure everything is at the same potential.

 

The lamp failing could be a bad socket, TP-22's sockets can overheat and the loss of spring tension on the pins causes arcing and failure.

[agedhorse]

 

Could even become energized through induction depending of how your cables are run. I once saw a bunch of PAR 64s hung on a pipe. They were terminated with stage pin connectors, and all the conductors were individual. The nice man installing it decided all the greens should get wrapped around the pipe together, then the whites, then the blacks. Can you say 97 volts to ground? Magnetic inductance is no joke, I'm sure Agedhorse has some great stories about that stuff with his experience in industrial power systems.

 

 

Very unlikely.

 

If all the wires were ultimately wrapped around the pipe, there would be no net magnetic field and thus no induced voltage or heating effects. It's no different than if a 3 wire extension cord was wrapped around. The net field is ~0. If there's 97 volts to ground, sounds like the failure of the insulation system in one of the lights or all of the lights or something like that since the pipe will be bonded through the fixture yoke also pulling it to earth potential regardless of what's happening.

[Redbassman86]

Apologies for the miscommunication. The green and white thhn was gaff taped to the pipe, and the blacks where wrapped. The green and whites were wrapped only where the fixtures were, but were gaffed the 30 feet down the old steel pipe to the dimmer rack, where as the blacks were wrapped the entire way. Must have gotten lazy and decided taping was better than gaffing!

[Redbassman86]

Oh, and the dimmer rack had a 3 to 2 cheater on the edison. Ground only works if the power knows what ground is....

[agedhorse]

Oh, and the dimmer rack had a 3 to 2 cheater on the edison. Ground only works if the power knows what ground is....

 

Ahhhh, a Darwin Award candidate obviously.

[Redbassman86]

The "venue" was located in an old mill (I'm from Rhode Island, all we have is old mills). It had a 480 corner grounded delta system. We went in there because the sound system was acting funny. Turns out the corner came un grounded, and burned a whole ton of stuff up. Best part, during a show, the switchgears phase to ground warning lights had started to light up, and no one knew what they were, so they unscrewed them and continued the show. After about 10 minutes, they said everything went black and the emergency lights came on (batteries), and the place emptied out. Thankfully the fire marshall was kind enough to shut them down once we informed them of the problems

[agedhorse]

I assume there were unit transformers for all 120/208 and 120/240 panels in the place??? Was the derived ground carried back properly and bonded properly?

[Redbassman86]

You should come out and see these old mills sometime. No unit transformers, MDP was a series of older Square D QO panels that supplied just 110, and 1 panel that supplied 240. One transformer for the 240 panel, and a 14.4 kV to 480 tranny where the ground was derived from. We had a fault in a roof top unit after we rebonded the low side of the service, and the 1in RMC that feed it shook like a bastard till the fault cleared. Place was totally unsafe, thats why it was shutdown

[agedhorse]

Yikes... now I understand the reasons for some of the obtuse code sections.We don't see much of that here in CA. Not many old mills... or really old buildings for that matter. A few in some big cities but the distribution has made big advances since they were built.

[Redbassman86]

Up until a few years ago, it wasn't uncommon around here to see 347/600 straight 3 phase services. Thank the gods they have all pretty much been phased out. Pardon the pun

[Coaster]

ever run into 2 phase up there? there still is some for some ungodly reason

[lifeloverwg]

 

Bonding the grid is a good safety measure, if it's attached to building steel that's already bonded to system ground then it's not necessary but the reason is to insure that the pip stays at ground potential regardless of what's brought in or what's happening around it. If you are up on a ladder and happen to grab building steel and the pipe, you want to be damn sure everything is at the same potential. The lamp failing could be a bad socket, TP-22's sockets can overheat and the loss of spring tension on the pins causes arcing and failure.

 

 

No building steel available unless you count the yet to be installed conduit. The hang pipe is lag screwed to 28" glue lams holding up a tongue and groove wood ceiling.

I'll have to look into the socket, the fixture that failed twice is an older Strand Century spot. The new bulbs I got for them are an Osram EHD.

Haven't had a chance to play around with the new dimmer that's not responding yet. I've never heard about needing to terminate DMX before. My LED's don't seem to care, but maybe this dimmer does....

 

Winston

 

Winston

[Dogoth]

 

I've never heard about needing to terminate DMX before. My LED's don't seem to care, but maybe this dimmer does.... Winston Winston

 

 

I found this info DMX Termination.

 

The LD at the venue I work at went years without terminating anything untill one day........ He looked up the proper way to wire the specific devices (I think they were older Roboscans? - Maybe I beams?) and this is what he found. When he terminated them properly, all problems went away.

 

Here's some sources for the premade plugs, if you don't want to solder

 

DMX termination PLUG

[dennis a]

 

I'll have to look into the socket, the fixture that failed twice is an older Strand Century spot. The new bulbs I got for them are an Osram EHD.

 

Examine the lamp that was in the fixture and look for burn marks or pits on one or both of the pins...that will indicate there are corresponding pits on the socket caused by arcing. The old pitted socket will continue to damage new lamp pins and if the new lamp with damaged pins is installed in a good fixture, the pitted area on the pins will cause arcing in the good socket.

 

Dennis

[Redbassman86]

Hahaha, two phase, I've really only seen that in books. Didn't that stuff get invented to make it easier to start electric motors. Being 90 degrees from each other certainly makes things more complicated in terms of distribution (more wires, bigger neutrals). You guys generate any of that where you are?

[Coaster]

around here? no. i have read about people finding it in the north east and not knowing it was 2 phase they proceeded to make a costly error.

[agedhorse]

 

No building steel available unless you count the yet to be installed conduit. The hang pipe is lag screwed to 28" glue lams holding up a tongue and groove wood ceiling. I'll have to look into the socket, the fixture that failed twice is an older Strand Century spot. The new bulbs I got for them are an Osram EHD. Haven't had a chance to play around with the new dimmer that's not responding yet. I've never heard about needing to terminate DMX before. My LED's don't seem to care, but maybe this dimmer does.... Winston Winston

 

 

DEFINATELY bond the pipe grid to the conduit system and be sure that's properly bonded all the way back to the service N-G bonding point. This is your fault current path.

 

The EHD is obsolete, there are much higher efficiency bulbs with compact filaments like the FLK, HX-600/1 etc. Smaller filament is better focused by the reflector and gives a smoother light field with higher light levels.

[IsildursBane]

I've been working on stage lighting for the Social Hall at my Church off and on for the last couple weeks. We have been taking stuff down from the Sanctuary, running multiple extension cords to power it and tearing it down setting it back up for the next service for years whenever we had a production in that space. We scored a bunch of free used curtain and old lighting fixtures from one of the local large theaters last year and we installed the curtain on the back and side walls for last years service trip fund-raising concert. (already had front curtain) This year I've been taking on lighting and power for the space. I got new black pipe up, new plugs and cords on the fixtures, new bulbs for said fixtures (we don't really need 750-1000w bulbs for a 20' throw), gel frames and gels, fixtures hung, some used and some cheap new dimmer packs purchase and ordered, DMX cable soldered up and strung and a contractor to run a 100 amp subpanel to the stage and circuits up to the hang points and walls. OK, so he's a contractor and only has the subpanel in and some temporary outlets hanging off of it in time, I take a deep breath, no big deal. At least I don't have to run extension cords as far this year. Dimmer packs arrive and get hung yesterday. We haul in the band gear and system to setup for the concert, setup goes smoothly, band practices for soundcheck and all's well. Time to aim and trim lights now that it's dark. Humm, dimmer pack not responding, up ladder, check settings, down ladder try again, back up ladder recheck address and settings, chase works, DMX doesn't, smells funny, loud pop right in front of my face and dimmer goes dark. One used dimmer pack down, that's not good. Down ladder with dimmer in tow. Fuses are fine, what to do? I decide I don't really need two dimmers for stage wash, so up another ladder, down with pack, back up first ladder, rehang and reprogram and we're up and running. Let's set a scene. First pack works now, second pack works fine, third pack not responding properly. Move second ladder, climb up, check settings and address, nothing, DMX signal light is good, my back stage LED fixtures beyond this pack are responding fine so it's not a cable issue. I power down the unit, unplug, replug, shake it, swear at it, one channel works in all settings, other three don't! Brand new out of the $55 box. Funny, it doesn't say Behringer on it....... but it is priced like it so what do I expect? After another hour of headscratching I give up, program one scene with front and back lighting and go home to bed. Can't sleep, thinking about lighting for now tonights performance. Looks like it's time for another extension cord and a couple of static wash fixtures for another year........ Crossing my fingers and praying to all the Gods that I've stabilized at this 50% failure rate. Time to head back out so maybe I can get a nap before showtime. I now hate lighting even more. Winston

 

You hung stuff without testing it?

 

-Dan.