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I fry my Red Head Bulb all the time. What am I doing wrongly? What Kind of generator should I be using?


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#1 Afolayan Dammy

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Posted 06 July 2015 - 02:53 PM

I hope to really get help and put and end to this. Let me start by saying electricity supply here in Africa isn't quite stable. We, most time depend on using generator. I have 3 Red head lights. I have bought 1 for close to a year and half now and I just got 2 more. But there is this issue I have. Before I got the other 2 redheads, my first redhead, I power it virtually with generator all the time. I use it most times for Night events that I cover but I have changed the bulbs for close to 5 times. I am always frying it. Normally when I use the light for not too long a shoot, say an interview, I usually don't have this problem. But when I am shooting for say, 3, 4, 5 hours, the bulb just suddenly goes off.(it doesn't explode, it just goes off). I would have to replace the bulb. Which I have done over 5times. I purchased two more red head and the first time I am using it to cover a night event, the two bulbs got fried that very night about 1 or 2 hours into the shoot. My question is, what is responsible for this???? The generator??? The Long hour of shooting??? Bad bulb???? What KW of generator should I be using to power the three lights? Is there something wrong somewhere??? I am tired of buying bulbs for every shoot. I am already saving to switch to using Kino flo very soon because of its ability to conserve power. But I know the Red head is quite very powerful especially as stage light because it produces very strong light as opposed to Kino flo that produces soft light. What am I doing that is burning my bulb
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#2 JD Hartman

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Posted 06 July 2015 - 03:40 PM

Unstable/over voltage from the generator.  If you were able to monitor and record voltage output over time (something like a Dranitz), I'd bet you would see a recorded spike in voltage when a bulb/globe/bubble/lamp fails.  With a Digital Multimeter or VOM, what is the voltage output of your generator?  220 or closer to 240 VAC?


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#3 Afolayan Dammy

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Posted 06 July 2015 - 05:17 PM

It is always 220V. Mind you, it is not one generator I'v been using for the lights. I have used various generators. The generator is usually provided by the owner of the event I am covering so I have use quite a number of generators. If it's a single generator I have been using all this while, I would have guessed and say it is the generator that is faulty
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#4 Afolayan Dammy

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Posted 06 July 2015 - 05:18 PM

It is always 220V. Mind you, it is not one generator I'v been using for the lights. I have used various generators. The generator is usually provided by the owner of the event I am covering so I have use quite a number of generators. If it's a single generator I have been using all this while, I would have guessed and say it is the generator that is faulty
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#5 JD Hartman

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Posted 06 July 2015 - 06:15 PM

Have you ever metered the output?  Are your lights the only load on the generator or is video village, HMU, etc., also tied into the same power?  Are these little portable units, 5-6Kw (put-puts), larger gas or diesel rigs, 100A , 250A?  Do they have a provision for manual voltage adjustment?


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#6 Afolayan Dammy

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Posted 06 July 2015 - 06:34 PM

I am not an electronics specialist and might not be able to give you all the specs. But I know the following. The generators I use are Petrol powered. Most times the lights are usually the only load on the generator since they consume much power. The generators I use are between 3.2KW to 6KW. When I use a generator of say 6KW, some other loads might be added on the generator since the three lights are only taking 2.4KW. Like I said earlier, I am not an electronics expert and so I don't know how to meter an output. I also don't know what is 100A or 250 A and I don't know if they have provision for manual voltage adjustment(although I do know of some generators where you turn a knob and the output is increased when too low or decreased when too high)
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#7 Afolayan Dammy

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Posted 06 July 2015 - 06:38 PM

Here is an example of the generator I use
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#8 JD Hartman

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Posted 06 July 2015 - 06:45 PM

Okay, we've established that they are portable generators, up to 6Kw.  Probably don't have a manual voltage adjustment.  Voltage is probably maintained by an electronic or more likely mechanical governor.  It's possible that this (internal) setting is no longer keeping voltage in a safe range for your bulbs.  Is there an Electrician around during an even or shoot who could check the voltage produced?


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#9 Afolayan Dammy

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Posted 06 July 2015 - 06:46 PM

He is a picture of one

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#10 Afolayan Dammy

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Posted 06 July 2015 - 06:53 PM

There is usually no electrician around most times
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#11 JD Hartman

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Posted 07 July 2015 - 09:07 AM

Is that image exactly the generator or just one similar to the portable generators you have to work with?  Do you experience the short lamp life on every generator or just some of the units provided?  You really need to find someone with a meter or buy one yourself.  Really simple to use.  Doesn't have to be digital to be useful.  


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#12 JD Hartman

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Posted 07 July 2015 - 10:04 AM

There is some pattern here, a trail of clues, that's causing you bubs/globes/lamps/bubbles to fail prematurely.  Something in the details that you are not telling us or not noticing yourself.  I'm just clutching at straws.....are the sockets tight and free from corrosion?


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#13 John E Clark

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Posted 07 July 2015 - 06:48 PM

There is a poster here, Guy Holt, who has a number of posts about using generators and movie lights. Unfortunately one does have to be a bit knowledgeable about electrical systems to understand what he is talking about, and how to understand your particular problem.

 

I would ask, what is the wattage of the 'red heads', and what is the power output of the generator. From the above, it seems the generator is 6KW.

 

I don't do power analysis much in the modern era, but my rule of thumb was to have twice as much power available from the generator as the load. So, if you had 3 1KW lamps, then 6KW is  a 'bare' minimum.

 

One thing that Guy Holt stresses, is that the HMI load is not a 'nice' load, and has what is known as odd harmonics. Again, this requires an understanding of Alternating Current, and how the devices that are powered by the generator respond.

 

You also have to understand that the power cord length from the generator to the HMI ballast can also affect how much power is delivered, or the effect of the harmonics may be.

 

Putting 100 feet (30 meters) of power cord between the generator (to cut down the noise of the generator heard at the set) may impact the power delivered.

 

I don't know if HMIs cutout because of low power, or increase the speed to failure if one does not have the correct voltage.

 

HMIs do require a cooling off period before striking the lamp again.

 

Here's an article on the topic of how much power for a generator to give, for some set of lamp wattages. It does get technical, unfortunately...

 

http://imaginenews.c...nerator-sizing/


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#14 JD Hartman

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Posted 07 July 2015 - 07:59 PM

It's not an HMI, it's a Tungsten fixture.  No harmonics, it's a pure resistive load. The wattage is either 800 or 1000w depending on which globe you choose.  A long run of light gauge power cord may introduce a voltage drop, but it's not going to cause globes to fail.


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#15 Gregg MacPherson

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Posted 07 July 2015 - 08:27 PM

Are the bulbs good? A good brand? Is the light overheating somehow? What brand is the light? What's the orientation of the light? Are you using glass dicroic filters? Just thinking out loud.

If you rig one of your lights off mains power, pointed sideways, with nothing on the front, how long does the bulb last?
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#16 Afolayan Dammy

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Posted 08 July 2015 - 10:17 AM

Thanks guys. Let me start by answering Hartman first. The picture above is exactly the type of generator I use 70% of the time. As regards the second question of, "Are the sockets tight.... Well an honest answer is, No! They are not. Infact they sometimes shake". And this is the reason. When I pass the wire to the generator, as you can see from the generator. It has only 2 outs to plug in. And I have three lights. So to improvise most times, this is what I do. I cut the later end of my wire,(which I av attached in picture) twist two together and send those two into one of the outs of the generator, then I send the third light which I have also cut the lower end to the second out. So at the end of the day, the wire enters into the generator but not very tight but that doesn't usually affect the light. If I decide to use the socket to connect the wire to the generator, I ll only be able to connect two lights. So I usually don't use that, I cut the wire, and join them together to be able to get two light to enter at the same time. So instead of connecting the wire to the generator like Picture B, which will be a tight connection, I connect it like Picture A. (I don't know if that is what you mean by if the connection is tight). Although sometimes, it shake. There is no corrosion however. Could that be the cause of my problem? John E. Clark, The bulbs are 800W and like I said earlier the generators I use are usually within the range of 3.2KW to 6KW since the three bulbs together is 2.4KW

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#17 John E Clark

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Posted 08 July 2015 - 01:37 PM

Ok, somehow I got the idea that they were HMIs... but from the pictures... uh... Were this my problem, I'd get a power strip with enough plugs for the number of lights, and that could carry the 2.5 KW requirements.

 

If there were no such power strip. I'd probably build one so that all plugs had their three prongs in contact, and nothing was left 'chance' with splicing or twisting the wires.

 

A hardware store should have the raw materials to do that. As a matter of fact, I've bought something like that to tie into power at conferences where the conferance

 

Something like this (this has standard US 3 prog plugs for distributing the power, but I'm sure there's a Euro/British version in your region.

 

 

 

162592_2000x2000.jpg


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#18 JD Hartman

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Posted 08 July 2015 - 02:42 PM

That's a twistloc to edison adapter not a "cube tap".  His lights are should have 220v bulbs in them.  You're confusing the issue.

 

Afolayan, does the volmeter on the generator you pictured work?  When two lights are plugged in what voltage does it read?  220 or closer to 240?


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