Dimming issue

[Craig Hauber]

I have home-made bars of 6 X 60W BR30. They are 6 individual bulb sockets on individual octagon j-boxes mounted about 2' apart on 10' sticks of unistrut.
A single circuit feeds all 6 and they have a 6' type SO pigtail with a 5-15 edison for powering. All bulbs are just basic 60W -no LED's.
I have 3 and a half sets all plugged into 1 channel of dimming for a total of 1260W
They have been there for a few years and working fine as backdrop lights.
When connected to our "new-to-us" but used Colortran i-series dimmer rack I get a jumpy & flickering quality of dim up or down. It holds fine at full but has the occasional subtle flicker-blink at levels below 100%
I tried a different dimmer channel with exactly the same results.
I've then run lekos and pars off all those same dimmers afterwards with smooth quiet dimming as normal.
Is there something about multiple small filaments that these dimmers don't like?
They are all the dual 2.4k modules in a 48ch rack that all channels work wonderfully with normal 500 to 1000W loads.

What's sad is I ran them off really cheap AmericanDJ 4ch packs and they behave much better. Still a bit of flicker (stepping) while fading, but they hold steady at partial dim.

Any suggestions or experiences with this type of dimming?

I'm going to take a string of festoon lights tonight and see if they behave similarily. As well I'm going to try adding a 1000W par can along with the backlights on the same dimmer to see if loading it down more would help

I do not have the software or a vintage MS-DOS computer to change any internal dimmer settings, nor do I have the "handheld remote"

 

[RonHebbard]

I have home-made bars of 6 X 60W BR30. They are 6 individual bulb sockets on individual octagon j-boxes mounted about 2' apart on 10' sticks of unistrut.
A single circuit feeds all 6 and they have a 6' type SO pigtail with a 5-15 edison for powering. All bulbs are just basic 60W -no LED's.
I have 3 and a half sets all plugged into 1 channel of dimming for a total of 1260W
They have been there for a few years and working fine as backdrop lights.
When connected to our "new-to-us" but used Colortran i-series dimmer rack I get a jumpy & flickering quality of dim up or down. It holds fine at full but has the occasional subtle flicker-blink at levels below 100%
I tried a different dimmer channel with exactly the same results.
I've then run lekos and pars off all those same dimmers afterwards with smooth quiet dimming as normal.
Is there something about multiple small filaments that these dimmers don't like?
They are all the dual 2.4k modules in a 48ch rack that all channels work wonderfully with normal 500 to 1000W loads.

What's sad is I ran them off really cheap AmericanDJ 4ch packs and they behave much better. Still a bit of flicker (stepping) while fading, but they hold steady at partial dim.

Any suggestions or experiences with this type of dimming?

I'm going to take a string of festoon lights tonight and see if they behave similarily. As well I'm going to try adding a 1000W par can along with the backlights on the same dimmer to see if loading it down more would help

I do not have the software or a vintage MS-DOS computer to change any internal dimmer settings, nor do I have the "handheld remote"

I'll offer two comments based upon similar experiences with a 1991 Colortran rack.
A large incandescent filament, such as a 1Kw PAR64, demonstrates what I'll call 'thermal inertia' in as much as it can neither come up to full operating temperature nor cool as quickly as a smaller, lower wattage filament, lamp; a 40 Watt incandescent filament for example. At one point I was playing head LX in a producing theatre where the curtain wash fixtures used FEL's and the large, central, house light chandelier was populated with 40 Watt G40 clear Fat Albert's for its main illumination and a great many 15 Watt clear normal lamps for the architect's 'beauty look'. The lower the wattages, the faster they were able to respond to every little burble in the Colortran's output. When the houselights were set at their nominal 'full' level; from memory, perhaps 60%, the lamps filaments weren't anywhere close to being up to temperature. When the houselights were at their nominal 'half' level, the filaments were operating even cooler and the jitters and burbles were even worse / more visible / more annoying.
Comment #2 involves how the Colortran rack was constantly trying to regulate its output voltage. Anytime it detected even the most momentary spike in its supply voltage, it would rapidly apply regulation as if the extremely short duration spike was a level it was consistently putting out. I 'baby sat' that rack from the opening of the venue in the fall of 1991 until New Years of 1993 and the 'dance' between the Colortran rack and the low wattage clear lamps was never-ending. A few feet across the dimmer room were four, original, Strand CD80-AMX192 full height racks which, aside from one fan bearing dieing prematurely, never exhibited any problems powering FEL's and 2 KW fresnels. I even had one of the small chandelier lamps in a pigtail socket plugged into an unused CD80 circuit in the LX booth and kept a couple of spare LP90 subs loaded with the standard 'house full' and 'house half' percentages just to prove that whenever the mains supply voltage became spikey / unstable, the Strand racks were exhibiting the same effect were they to be driving the same lamps as the Colortran. The Colortran rep' cheered when I demo'd the problem to him; the Strand rep' not so much.
Edit: I'm not suggesting the Strand racks were using regulation, no. I'm just pointing out they were passing the spikes through and they were nearly as visible with the clear, low wattage, lamps dimmed to similar level.s
I'll quit blathering.
Toodleoo!
Ron Hebbard.

 

[Amiers]

I would load it down but start with a 500w Par before going straight to a 1000w Par. I don't think the festoon lights are going to help much.

 

[Craig Hauber]

I would load it down but start with a 500w Par before going straight to a 1000w Par. I don't think the festoon lights are going to help much.

Been quite busy getting the show open and avoiding sitting in front of the computer (I in solo am the entire set, electric and tech department) -nonetheless, thanks much for the replies!
I was just going to use the festoons to see if the dimmer's behavior was the same, not as a ghost load.
-and it acted the same, -like what Ron was describing. Adding a 500W fresnel didn't help either, it dimmed nicely but the small bulbs still behaved the same
I went with the el-cheapo ADJ satellite packs to run them for this show and will try to figure out a solution before the next show (next year). I am thinking of just going to a larger bulb (120W or even 200) We have the dimmer capacity now and I really could use more light back there.
I did read that there is quite a few settings that can be made in the dimmer using software through a serial port on the front of the control module. I found a working DOS box with floppy drive and serial port -if anyone has the software utility I could certainly use a copy.

 

[STEVETERRY]

I have home-made bars of 6 X 60W BR30. They are 6 individual bulb sockets on individual octagon j-boxes mounted about 2' apart on 10' sticks of unistrut.
A single circuit feeds all 6 and they have a 6' type SO pigtail with a 5-15 edison for powering. All bulbs are just basic 60W -no LED's.
I have 3 and a half sets all plugged into 1 channel of dimming for a total of 1260W
They have been there for a few years and working fine as backdrop lights.
When connected to our "new-to-us" but used Colortran i-series dimmer rack I get a jumpy & flickering quality of dim up or down. It holds fine at full but has the occasional subtle flicker-blink at levels below 100%
I tried a different dimmer channel with exactly the same results.
I've then run lekos and pars off all those same dimmers afterwards with smooth quiet dimming as normal.
Is there something about multiple small filaments that these dimmers don't like?
They are all the dual 2.4k modules in a 48ch rack that all channels work wonderfully with normal 500 to 1000W loads.

What's sad is I ran them off really cheap AmericanDJ 4ch packs and they behave much better. Still a bit of flicker (stepping) while fading, but they hold steady at partial dim.

Any suggestions or experiences with this type of dimming?

I'm going to take a string of festoon lights tonight and see if they behave similarily. As well I'm going to try adding a 1000W par can along with the backlights on the same dimmer to see if loading it down more would help

I do not have the software or a vintage MS-DOS computer to change any internal dimmer settings, nor do I have the "handheld remote"

FYI, there were some known bugs in Colortran I-Series that resulted in them being replaced in at least one major venue of about 1000 dimmers in Las Vegas, after the venue lost a show. The major bug showed itself as uncontrolled flicker, such as you describe, under certain conditions of line voltage and harmonic distortion. If this is indeed your bug, I think it is very unlikely that changing user-configurable settings will fix it.

ST

 

[Craig Hauber]

FYI, there were some known bugs in Colortran I-Series that resulted in them being replaced in at least one major venue of about 1000 dimmers in Las Vegas, after the venue lost a show. The major bug showed itself as uncontrolled flicker, such as you describe, under certain conditions of line voltage and harmonic distortion. If this is indeed your bug, I think it is very unlikely that changing user-configurable settings will fix it.

ST

Since it seems to be happening on only that channel -and even then it's far from a show-stopper -I'll just work on fixing the load as the dimmer works fine on all other conventionals.
It was a graciously donated system (48ch iSeries and Encore 24/48 console) which is such a wonderful upgrade to the mbt/lite-puter satellite packs we used to use coupled to the worst theater-lighting desk ever (Behringer eurolight LC2412).

Doesn't say much for Colortran/Leviton that they couldn't fix that problem in that LV venue -and would lose a 1000ch sale! Dimming is such a simple thing that many others have gotten it right over the last 100 years!

We are in a rural building with our own little pole transformer and 100A single-phase service -so I'm sure our power isn't the best