Jump to content


Photo

Major Headaches with my distro system


  • Please log in to reply
23 replies to this topic

#1 J. Lamar King

J. Lamar King
  • Basic Members
  • PipPipPipPip
  • 764 posts
  • Gaffer
  • Los Angeles

Posted 24 July 2008 - 02:19 AM

Maybe someone with deep knowledge of distro and generators can solve this one for me. Never had this problem until recently on my last feature during the last week one day we fired an 18K and used it for about an hour. We then fired up another 18K then about 15 minutes later the 1st one shut off, 5 minutes after that the second one shut off. This started to happen every day with all different combinations of lights. Mostly I could run an 18K and a 6K at the same time. Today two months later on another feature same equipment vendor we get the same problem. Never had it in the past for three features.

So today I was running a 1400amp genny, 3-phase 208, 50' of banded to threefers then two runs of banded 100 feet each. LTM 18K/Power Gems ballast on one run. LTM 12K PAR/Power Gems and LTM 6K PAR/Power Gems on the other run. 18K went down first, we restruck when cooled. Then 5 minutes later everything goes down. Restruck 18K only and it stays up. Genny is running at 210 volts measured. I find a warmish threefer on the black leg but nothing abnormal. Genny is running at 60.03hz I adjusted it to 60.00 to .01hz. Those are hundredths of a HZ so I don't think that was the issue.

We saved the 18K to move it to another position. This time I have to have all of my lights. Fingers crossed I struck the lights in order this time. 6K first, then 12K, then 18K everything ran for the rest of the day.

The last time this happened I thought I had tracked down the cause. I found two sticks of 2/0 that had been run over and crushed by the water truck. (crossovers do no good if the drivers won't aim for them!) This time it's the first day of shoot everything checked out fine the day before. I don't think it's the lights or ballast themselves because I've used so many heads,ballasts,feeder combinations and still have the problem. The only other clue I have is sometimes the ballast read "Ground Trip" as opposed to "Output Ground Loop Trip" which is the head feeder or microswitch.

Any ideas what could cause this vicious anomaly? Other than LTM must be French for POS. I suspect a bad ground connector somewhere but I have brand new D-boxes. Maybe I'm lucky enough to get the same bad stick of banded or bad threefer again. Tired of having a heart attack then fanning 18K's all day.

Edited by J. Lamar King, 24 July 2008 - 02:20 AM.

  • 0

#2 timHealy

timHealy
  • Basic Members
  • PipPipPipPip
  • 1252 posts
  • Other
  • New York

Posted 24 July 2008 - 05:45 PM

Good explainatinon of your issue.

I don't think you did anything wrong.

I doubt it was a voltage drop issue being so close to the generator but were you able to read the voltage at your distro box or where your camlock T's were providing power to the ballasts? And read voltage with the lights on?

Did you say you ran banded number 2 your from your generator? I think banded was a bit too small for that load. I mean you can get away with it, but 2/0 would have been better. You would have had about 150 amps on your high leg. But with such a short cable run, it should have been ok.

My second guess would be some wacky harmonics issue. I would had tried disconnecting the ground from the generator and operating without one or try an earth ground if possible. (when I write ground I mean the Ground and not the Neutral as some older electricians refer to the Neutral as a ground) Regardless of what electric codes say. It would have been worth a shot to keep your lights on. The light was saying ground trip like thee was a short or something.

Having experienced wacky things with HMI's and generators is the past, I would love for the light manufacturers to get together with the generator manufacturers and figure some of these issues out.

Best

Tim

Edited by timHealy, 24 July 2008 - 05:47 PM.

  • 0

#3 Paul Bruening

Paul Bruening

    (deceased)

  • Sustaining Members
  • 2858 posts
  • Producer
  • Oxford, Mississippi

Posted 24 July 2008 - 10:51 PM

I don't know too much about the topic. What I do know is from my own 3Ph genny. All three legs have to be within 50% load of each other. If you were running 2 18Ks then the remaining leg may have been out of balance and the safety system may have shut the whole rig down. Like I said, I don't know a lot about it. It's just something to factor in.
  • 0

#4 Andrew Koch

Andrew Koch
  • Sustaining Members
  • 243 posts
  • Cinematographer
  • Burbank, California

Posted 25 July 2008 - 12:52 AM

My second guess would be some wacky harmonics issue. I would had tried disconnecting the ground from the generator and operating without one or try an earth ground if possible. (when I write ground I mean the Ground and not the Neutral as some older electricians refer to the Neutral as a ground) Regardless of what electric codes say. It would have been worth a shot to keep your lights on. The light was saying ground trip like thee was a short or something.


I don't mean to be harsh, but this very irresponsible advice. Don't even think about running an AC system without being completely grounded. If there is a short in any of the equipment, you will not be protected and the results could be fatal. It is totally not worth risking killing people on set to keep some lights on. It is also illegal. When someone dies, the authorities will ask why you didn't ground your genny. "We needed to get the shot" won't cut it. You could try an earthed ground as Tim suggested as long as it is done properly.
  • 0

#5 J. Lamar King

J. Lamar King
  • Basic Members
  • PipPipPipPip
  • 764 posts
  • Gaffer
  • Los Angeles

Posted 25 July 2008 - 05:34 AM

Hey guys thanks for the reply. I would never pull a ground, too dangerous. I think we were within limits with the banded. If it was any hotter outside I would have ran 2/0 feeder. Anyway I think I've remedied the problem and I wonder why I didn't think of it in the first place. Production has been plugging in those mobile A/C units on my lines. :blink: I'm convinced that when the compressor kicks on in those things that it draws a ton of voltage out of the lines. That sag in turn shuts some or all of the lights off. Those A/C units showed up for the first time on the last show exactly when this problem started. Now on this show we have it again. I didn't burn any HMI's today but tomorrow I will and those A/C units are out. If I don't have any problems then they are never going back on my runs that's for sure.
  • 0

#6 Andrew Koch

Andrew Koch
  • Sustaining Members
  • 243 posts
  • Cinematographer
  • Burbank, California

Posted 25 July 2008 - 12:31 PM

I was best boy on a show where production kept plugging in an air compressor without telling me. The breaker kept tripping. We were shooting on a backlot and the art department for some big budget commercial was setting up next door. They kept plugging in their air compressor into one of my lunch boxes without asking me. Even after we told them to cut it out, they tried to do it again. Considering, that our own production's compressor was tripping the breaker, I was pretty irritated at the other production.
  • 0

#7 timHealy

timHealy
  • Basic Members
  • PipPipPipPip
  • 1252 posts
  • Other
  • New York

Posted 25 July 2008 - 08:48 PM

I don't mean to be harsh, but this very irresponsible advice. Don't even think about running an AC system without being completely grounded. If there is a short in any of the equipment, you will not be protected and the results could be fatal. It is totally not worth risking killing people on set to keep some lights on. It is also illegal. When someone dies, the authorities will ask why you didn't ground your genny. "We needed to get the shot" won't cut it. You could try an earthed ground as Tim suggested as long as it is done properly.


I suggested disconnecting the ground in terms of trouble shooting. And the whole grounding of a generator is a whole can of worms for another thread. The NEC says one thing. The LA teamsters/genny ops say something similiar, and anyone who works in places where it rains a lot have a different opinion. And then there's the issue of a proper earth ground. A proper earth ground by NEC standards is not really feasible in cities where there are all sorts of things underground like electrical lines, water lines, gas lines, telecommunications lines etc etc.

Just a note. Movies were made for decades without grounds. It has only been since the mid 90's, from my experience that studios, production companies and rental houses have been serious about a grounded systems. That is when "entertainment cable" replaced other types of cable in use.

Best

Tim
  • 0

#8 timHealy

timHealy
  • Basic Members
  • PipPipPipPip
  • 1252 posts
  • Other
  • New York

Posted 25 July 2008 - 08:51 PM

Hey guys thanks for the reply. I would never pull a ground, too dangerous. I think we were within limits with the banded. If it was any hotter outside I would have ran 2/0 feeder. Anyway I think I've remedied the problem and I wonder why I didn't think of it in the first place. Production has been plugging in those mobile A/C units on my lines. :blink: I'm convinced that when the compressor kicks on in those things that it draws a ton of voltage out of the lines. That sag in turn shuts some or all of the lights off. Those A/C units showed up for the first time on the last show exactly when this problem started. Now on this show we have it again. I didn't burn any HMI's today but tomorrow I will and those A/C units are out. If I don't have any problems then they are never going back on my runs that's for sure.


How large were these air conditioners?

Though it is never a great idea to have ac's on the same generator as HMI's, you had a 1400 amp genny and you were using about 25 to 35 percent of it's capacity.

And I wonder why production was plugging them in without asking the electricians.

Best

Tim
  • 0

#9 J. Lamar King

J. Lamar King
  • Basic Members
  • PipPipPipPip
  • 764 posts
  • Gaffer
  • Los Angeles

Posted 26 July 2008 - 06:03 AM

How large were these air conditioners?

Though it is never a great idea to have ac's on the same generator as HMI's, you had a 1400 amp genny and you were using about 25 to 35 percent of it's capacity.

And I wonder why production was plugging them in without asking the electricians.

Best

Tim


They are the small portable studio ones that run off 120. The only thing I could find on the unit was 8 amps. I don't believe that though. Maybe when it's just blowing but every time the compressor kicks on I know it draws down a pretty big amount of power quickly. In fact I noticed it would dip the tungsten lights in the lunch box it was plugged into also some of the units would trip the breaker. Unfortunately the call sheet changed and we did all Night Int. today so I didn't burn any big guns. I'll feel confident the problem is solved if I can get through a few days with no problems with my guns and no A/C's on my lines.

I was aware they were being plugged into my system but it was one of those political things where you feel you have to help out. But if they are causing a problem production is going to have to keep a small genny around just for the A/C units which they did today.
  • 0

#10 Andrew Koch

Andrew Koch
  • Sustaining Members
  • 243 posts
  • Cinematographer
  • Burbank, California

Posted 26 July 2008 - 03:53 PM

A proper earth ground by NEC standards is not really feasible in cities where there are all sorts of things underground like electrical lines, water lines, gas lines, telecommunications lines etc etc.

Just a note. Movies were made for decades without grounds. It has only been since the mid 90's, from my experience that studios, production companies and rental houses have been serious about a grounded systems. That is when "entertainment cable" replaced other types of cable in use.

Best

Tim



I agree about the earthed ground. In a city like LA it is safer and more practical to have a floating ground and this is legal in Los Angeles. In response to the second paragraph, movies were made for decades without grounds because everything ran on direct current which doesn't need to be grounded. With the advent of HMI's the industry had to switch to AC. This resulted in a need for a grounded system. Just because things were done in the past doesn't make them okay (asbestos in costumes and curtains for example). But I must apologize for hijacking the thread. You are right tim, this is more appropriate for another thread.
  • 0

#11 timHealy

timHealy
  • Basic Members
  • PipPipPipPip
  • 1252 posts
  • Other
  • New York

Posted 26 July 2008 - 08:14 PM

I agree about the earthed ground. In a city like LA it is safer and more practical to have a floating ground and this is legal in Los Angeles. In response to the second paragraph, movies were made for decades without grounds because everything ran on direct current which doesn't need to be grounded. With the advent of HMI's the industry had to switch to AC. This resulted in a need for a grounded system. Just because things were done in the past doesn't make them okay (asbestos in costumes and curtains for example). But I must apologize for hijacking the thread. You are right tim, this is more appropriate for another thread.



Andrew,

I wasn't referring to DC. I was specifically talking about AC ungrounded systems which did occur. Sure it may not have been "legal" or to code, but a lot of what films do are only temporary and filmmakers have gotten away with a lot over the years. Look at a tie in's for example. Many don't think it is "legal" but they occur everyday all over the country. I'm not advocating the use of ungrounded systems, I was just referring that they did indeed exist and were used. I was saying so to support the idea that one can unplug a ground during your shoot trying to solve a problem. grounds are actually disconnected all day long on a shoot as more HMI's are added. The neutral on the other, is the only thing one cannot disconnect in that manner as I am sure you know.

Best

Tim
  • 0

#12 timHealy

timHealy
  • Basic Members
  • PipPipPipPip
  • 1252 posts
  • Other
  • New York

Posted 26 July 2008 - 08:16 PM

They are the small portable studio ones that run off 120. The only thing I could find on the unit was 8 amps. I don't believe that though. Maybe when it's just blowing but every time the compressor kicks on I know it draws down a pretty big amount of power quickly. In fact I noticed it would dip the tungsten lights in the lunch box it was plugged into also some of the units would trip the breaker. Unfortunately the call sheet changed and we did all Night Int. today so I didn't burn any big guns. I'll feel confident the problem is solved if I can get through a few days with no problems with my guns and no A/C's on my lines.

I was aware they were being plugged into my system but it was one of those political things where you feel you have to help out. But if they are causing a problem production is going to have to keep a small genny around just for the A/C units which they did today.


I'm surprised small air conditioners would cause this. I would still suspect harmonics, or perhaps one ballast acting weirdly that affects the others.

Tim
  • 0

#13 David Auner aac

David Auner aac
  • Sustaining Members
  • 1117 posts
  • Cinematographer
  • Los Angeles

Posted 27 July 2008 - 07:54 AM

I'm surprised small air conditioners would cause this. I would still suspect harmonics, or perhaps one ballast acting weirdly that affects the others.


I once had a strange issue with the ballast of an HPL light. The minute you plugged the ballast in, a normal 12DC on the same circuit motor with built in transformer wouldn't start. It would kick, and nothing else. When I unplugged the ballast all went back to normal immediately! At times ballasts are wacky things indeed!

Cheers, Dave
  • 0

#14 J. Lamar King

J. Lamar King
  • Basic Members
  • PipPipPipPip
  • 764 posts
  • Gaffer
  • Los Angeles

Posted 31 July 2008 - 02:34 AM

Update: I'm still screwed. :angry: Yesterday I ran my two replacement 18's and a 6K all day no probs. Today however I got no strike from either 18K! One ballast kept saying 'Lamp did not ignite' and the other was just displaying giberish. Finally I got one 18K to strike and it ran about 30 minutes then shut off. WTF! I went through everything again can't find anything wrong with distro or Genny. No A/C's on the line either. I was able to keep a 12K, 6K and 4K up with no probs so we got through the day. Rental house can't seem to help either. So I'm just going to get a different set of 18's from a different rental house. I can believe this shi-ite! :blink:
  • 0

#15 timHealy

timHealy
  • Basic Members
  • PipPipPipPip
  • 1252 posts
  • Other
  • New York

Posted 31 July 2008 - 08:24 PM

Update: I'm still screwed. :angry: Yesterday I ran my two replacement 18's and a 6K all day no probs. Today however I got no strike from either 18K! One ballast kept saying 'Lamp did not ignite' and the other was just displaying giberish. Finally I got one 18K to strike and it ran about 30 minutes then shut off. WTF! I went through everything again can't find anything wrong with distro or Genny. No A/C's on the line either. I was able to keep a 12K, 6K and 4K up with no probs so we got through the day. Rental house can't seem to help either. So I'm just going to get a different set of 18's from a different rental house. I can believe this shi-ite! :blink:


Hey Lamar,

Sorry to hear about this.

Did you try anything different?

Like making sure your cable runs are large enough to rule out voltage drop? I mean the cable itself.
Have you tried the alternative ground? Just for the hell of it?
If you aren't shooting off speed maybe you need to take out backup magnetic ballasts until the problem is solved. The rental company shouldn't charge for them.

I'll e mail some friends here if they have come across this issue.

Best

Tim
  • 0

#16 J. Lamar King

J. Lamar King
  • Basic Members
  • PipPipPipPip
  • 764 posts
  • Gaffer
  • Los Angeles

Posted 01 August 2008 - 03:20 AM

Yeah it's been a real pain in the A... I went through the whole system with the genny op, had the rental house come out and take a look and they brought us two more 18K's. Today we were really meticulous with balancing the legs and running the replacement lights. We ran an 18, 12 and 4K all day with no problems. Maybe it's just down to bad ballasts. All of these problems and it's only day 7 of 24...we'll see how it goes.
  • 0

#17 JD Hartman

JD Hartman
  • Basic Members
  • PipPipPipPip
  • 1690 posts
  • Gaffer
  • Edison, N.J. U.S.A.

Posted 03 August 2008 - 07:14 PM

In the process of elimination, what have you done? When you encounter a head going down, have you tried striking it from a distro box closer to the generator? Have you checked all the "T"s, camloks and distro boxes at the time that a head goes down to see if any of them are unusually warm, given the load? It almost seems like you need someone with a power line monitor with logging capability like a Dranitz to capture the data from the event as it happens.
  • 0

#18 J. Lamar King

J. Lamar King
  • Basic Members
  • PipPipPipPip
  • 764 posts
  • Gaffer
  • Los Angeles

Posted 05 August 2008 - 09:14 PM

Well now I've learned that I'm really just having an old fashioned under voltage issue. I ran 4/0 feeder every day since the last time I had trouble and watched the voltage very closely. On banded we were losing quite a few volts per hour not mention when we added a light. This combined with the A/C's was causing the problem. I have had no trouble the last few days with bigger cable and making sure the voltage remained stable. I never have really had to be as sensitive to voltage before. Not sure what's different, I guess it's the genny. Seems that when we first send power down and take a reading, turn on our lights adjust voltage etc. it's good but then 45 minutes later the volts have dropped quite a bit.
  • 0

#19 timHealy

timHealy
  • Basic Members
  • PipPipPipPip
  • 1252 posts
  • Other
  • New York

Posted 08 August 2008 - 10:45 AM

I'm glad you found your problem. Many people run cable that they think will save work but cause more work in the long run. Running heavier gauge cable keeps you safe. If you start getting into runs as long as 400 or 500 feet you'll have to start double pumping to keep your voltage up. One sure sign of voltage drop is that one light goes out when you strike another. It may be worth rereading the Harry Box Book coverage of the issue.

But one thing puzzles me. Voltage should not drop per hour. If your load is consistant and the run a fixed length, voltage should be steady. Unless the generator is malfuctioning. Which is possible. Voltage regulators breakdown and voltage adjustment reostats get dirty or corrode.

Best

Tim
  • 0

#20 Paul Bruening

Paul Bruening

    (deceased)

  • Sustaining Members
  • 2858 posts
  • Producer
  • Oxford, Mississippi

Posted 08 August 2008 - 11:30 AM

How many hours does the genny have on it? Mine's pretty old and can only put out 3/4s of its rating. If it has a lot of hours on it, it will drop its load capacity some as the jugs get hotter and the pistons get sloppier.

Smaller cable at its limits makes heat. If the system is running at its limit on that gauge, then the heat in the cable eats more volts. Overdriving the cable to compensate makes more heat, eats more volts. You can end up driving two types of devices: Lighting systems and a heating system.

That's one of the benefits of living in Mississippi. We're, basically, codeless for temporary set-ups. If the local city engineer thinks it's okay, then he nods on it. If they know that you know what you're doing and patching in below the mains, they don't even check on you. Our local guy lets us use welding cable for feeders. The fine strands of welding cable carries juice very efficiently. We really love our local guys.
  • 0


Paralinx LLC

Metropolis Post

Ritter Battery

Opal

Broadcast Solutions Inc

The Slider

Wooden Camera

Visual Products

Abel Cine

Media Blackout - Custom Cables and AKS

Aerial Filmworks

Glidecam

Rig Wheels Passport

rebotnix Technologies

Technodolly

Willys Widgets

Tai Audio

CineLab

Gamma Ray Digital Inc

CineTape

FJS International, LLC

The Slider

Metropolis Post

Glidecam

Gamma Ray Digital Inc

Technodolly

CineLab

Abel Cine

Media Blackout - Custom Cables and AKS

Visual Products

Willys Widgets

rebotnix Technologies

Rig Wheels Passport

Wooden Camera

Ritter Battery

Paralinx LLC

CineTape

Broadcast Solutions Inc

Opal

Tai Audio

FJS International, LLC

Aerial Filmworks