Monoblocs and the Generator

[timberwolf1]

James, what this E.E. is saying is to attach a small wattage bulb in-line to the mono light to

be used as an indicator of voltage health. If the light becomes too dim, you are in trouble.

 

I believe that you cannot use the generators you have selected on anything but slow

recycle mode. Connecting a 10 watt bulb and watching it while the unit recycles will tell

you how overextended you are.

 

He is also saying that "amps" really is the marking to follow. This is because 240 volts in

your country will have a different amps rating than the 120 volts in the US. While

"Watts=work" watts doesn't clearly tell the whole story. You need to only get estimates in

volts and amps.

 

You should call Broncolor to find out exactly what the peak and continuous demand is for

your mono lights as a total group of 3.

 

I called several sources for my 2.5-3.0 peak demand rating for flash unit usage on

generators. Because flash units typically use the large can type of capacitor, they draw

current in similar loads, I believe. Anyway, I confirmed that all American brands of flashes

need at least 2.5x factor from Holly Flash and the Flash Clinic. Using a 3.0x factor is

simply more conservative, and this is what Speedotron gave.

[timberwolf1]

This E.E. is also implying that you need to use the correct cord for 240 voltage rather than

using US 120 volt cords. This is because the cords are wired internally differently for AC.

they are not merely thicker or thinner.

 

Your 2 Honda EU20i have an amperage rating, you should find out exactly what this is. It

is probably 1/2 of the EU2000i generator because they are 240 volts. Taking this number,

you add up the three units you want to plug in to the generator and times this figure by

2.5 or 3.0. The resultant number should be smaller than the total amperage of your

generators.

 

You see, the problem here is that you could be talking to someone overseas who assumes

you are using a 120 volt system. He will speak to you in watts or amps, and his figures

will be totally wrong for you because you are using 240 volts.

 

The figures I used above were for 120 volts because I have figures on the internet to look

at. However, I could not find the ratings for 240 volt generators. Their amp rating

SHOULD BE a amp number which is 1/2 of the rating for 120 volt systems.

 

At any rate, you are now aware that you should make it clear to anyone you talk to that

you have a 240 volt problem, and that you want figures that relate only to 240 volt

systems. I am making this very clear because while I think you understand this, james, I

want the readers to understand this.

[timberwolf1]

I want to know where to put this indicator light in-line to the mono light. I know that

current flows in one direction while electrons flow in the other. So, how does this affect

voltage spikes and their attenuation with a 10 watt bulb? Where in the wiring of Ac would

you put the bulb for an 240 volt system? And where in the wiring would you put the bulb

for 120 Volt Ac in the US? Would it matter? Is this because the bulb is non-polarized?

Would the bulb be placed into the circuit just like any other device?

[timberwolf1]

I have read that gasoline begins to degrade, turn to shellac, in about a month. Therefore,

you need to store a generator "dry" if possible.

[kelly_flanigan1]

Timber; Radio Shack (Yuk!?) of all places used to carry an expanded scale voltmeter that has a regular wall plug; a grey module with an analog meter. It read from about 100 to 130 volts; and allowed one to eyeball the voltage. Theses are only accurate to a few volts; but are simple. <BR><BR>Placing a 5 to 15 watt bulb near your load; ie; your flash can help with spikes. we did this before "spike protective plug strips" were common.. You can also just use a plug strip that has spike protection; these are cheap now. These have MOV's; which capture very sharp spikes in nanoseconds. <BR><BR>

[kelly_flanigan1]

Storing the generator dry is a maybe. Msot carbs will still have gasoline in the fuel bowls; which drys and gums up with time. Ancient motors had bowl drains; to remove all the gasoline. Today it is easier just to fire the generator up once every month or two.

[kelly_flanigan1]

When the gasoline evaporates; the "dregs" is what is left. It looks like amber varnish; or sometimes asphalt! this is waht gums up the needle valve(s).

[timberwolf1]

These "MOV"s, isn't this all about bleeding a capacitor to a ground? I put a question on

photo.net if you want to move the discussion over there.

 

I want to correct a statement I made above regarding transiet/ constant load. The 2.5-3.0

factor is actually based upon the fuse rating, not any constant load factor. In this way, I

was able to easily understand how much over the fuse rating the flash unit actually

peaked. A "constant load" would be like a motor spinning; flash units don't behave exactly

like motors because they "fill up" and then "stop". Therefore, forget my purloined useage

of terminalogy that the E.E. pulled in.

 

The reader should simply look at the fuse and find its rating. You would then use a

generator which would output 2.5-3.0 times what this amp rating is next to the fuse.

Thus, if the fuse says 5.0 amps, you would use a generator of 12.5-15.0 amps output.

[john falkenstine]

Excellent forum. You just caused me to cancel a planned Generator I was going to use this summer..

[timberwolf1]

MAGNETIC FIELDS, MONO LIGHTS, GENERATORS:

 

All Generators produce a strong magnetic field around it. This magnetic field adversely

effects semiconductors, SCRs, used in flash packs whether the flash pack has a computer

chip in it or not. In order to reduce this bad effect upon your mono light or flash pack,

the generator should be at a 18-20' distance from from the flash pack or mono light.

 

The exception to this rule is if the pack or mono light uses a steel case. The steel case

acts as a shield from this magnetic field. Many flash pack cases are aluminum or plastic,

not steel. These materials will not shield the unit from magnetism. Speedotron uses steel

cases, and the unit is highly favored by car photographers who use several of them while

connected to large generators. Other brands of packs and mono lights, like Lumedyne, do

not use steel cases. This is something you should investigate. A lightweight unit may be

made of aluminum.

 

At any rate, distance the unit from the generator. Even though this may mean adding an

extension cord, do it.

 

MY SOURCE: HOLLY FLASH

 

Timber Borcherding timberborcherding

[timberwolf1]

So called "Perfect Sine Wave" cannot be generated by a portable generator says Techs at

Holly Flash. Why? Generators use brushes, and these cause electrical noise. The noise

distorts the "perfectness" of the sine wave. This distortion should be filtered out by an

accessory noise filter. Lower cost generators, contractor grade generators may say they

produce a "perfect sine wave", but they don't have sophisticated filtration for electrical line

noise.

 

CYCLES PER SECOND VARIATIONS

 

According to my sources, even if the cycles per second were to dip to 50 HZ instead of the

regular 60 Hz, you are OK. Therefore, if the RPMS of a cheap industrial generator varies

alittle, no problem will result when used with a flash pack. Voltage surges can be

tolerated with flash packs, too. It was recommended to me to leave the 'voltage regulation

mode" turned off with flash pack usage. What is necessary is to have a electrical noise line

filter and spike protection.

 

Naturally, a generator that has all the features in one will be more expensive. But if you

go the cheaper route with a contractor grade generator, you know what you need to add

and the rule for distancing the unit from your pack/mono lights.

 

So, here are a few new generator usage in the field rules to add to your kit.

Source: Holly Flash

 

Timber Borcherding timberborchering

[j p]

My shoot is tomorrow for the next 3 days out in the middle of no where (fashion

campaign) Unfortunately the parallel leads connecting 2 x 2kva generators(EU2000i)

together is out of stock in australia for at least the next 3 weeks. So back 2 square 1,

rental of 3 Broncolor mobil kits + 4 heads and spare batteries with a recharge every night.

Boring

But good feedback

[timberwolf1]

I think the more idea situation is to rely upon a battery powered system like a Balcar Aq

1200 which could use a light weight generator to simply keep the batteries charged or

near charged in the field. The batteries, therefore, take all the abuse and they deliver even

voltage, no noise, etc.

 

If you cannot use the better EU's, my source says that a noise and spike protected cheaper

industrial generator could work. But the way I feel about Broncolors and Speedotron

Force 10s is that I would not want to feed them "dirty current". I would rather just go

with a Speedotron Brownline system for its transformer-based system. This type of

system can take "dirty current". The modeling lights, on the Brownline system are limited

to about 100 watts though.

[lbi115l]

My Speedotron 2401a will run off of a Honda 2500 watt (2300 rated) gas generator as long as it is in slow recycle. In fast recycle, the load is so strong that the generator will stall. Not good for either the equipment or the generator. This pack is rated at 20A but supposedly draws about 60A in fast recycle, presumably about 40A in slow.

 

I would suggest that if you're working with lighting equipment, you learn at least a little about the science behind it.

[timberwolf1]

What is nice about the above post is that it disproves that a 2400 watt generator can

power a 2400ws strobe pack. In otherwords, the fact that flash packs have a "peak" of

current that surpasses the fuse rating on the pack has been verified above.

[timberwolf1]

This is a quote from www.honda.com:

 

Regarding "EU" top of the line generators:

 

"Computers and power-sensitive testing equipment require what is referred to as �clean

power.� Clean power is electrical current that is consistent and has a stable �sine wave� or

signal. If the lights or other basic appliances in your home were being powered by a

generator and there was a fluctuation in the AC power, you�d probably see the lights dim

and then return to full brightness�no problem! However, if your computer was being

powered by a generator and the voltage fluctuated, chances are the computer would either

shut down or at least interrupt the program you were working in.

 

In order to overcome this problem, Honda engineers developed a revolutionary form of

inverter technology. This process takes the raw power produced by the generator, passes

it through a special microprocessor that provides ultra-clean power that boasts a sine

wave equal to or better than the current from your household AC wall outlet. This means

that for the first time, you can operate a computer or other sensitive equipment from a

remote location without the fear of interrupted service or damage to the equipment.

 

Honda�s unique inverter technology also dramatically reduces the size and weight of the

generator. This reduction is possible thanks to the fact that Honda EU-type generators

have the alternator built into the engine itself, eliminating the need for a bulky (and heavy)

independent alternator. The EU3000is model is actually half the size and weight of our

top-of-the-line EX3300 model."

 

It sounds like it uses a alternator to produce AC which is probably feed into a diode to

make DC and then the result is fed into an inverter to clean it all up and output a "perfect

sine wave". If this is the case, the inverter isolates AC noise. So, maybe the EU3000is

actualy creates this perfect sine wave.

[timberwolf1]

I'll just summarize in one place some of the choices for portable power and flash unit

usage:

 

1. Buy a battery portable flash such as Profoto 7b or Balcar Aq 1200. Attach a slow

charger to it, such as a 2 amp charger which is connected to a small generator like a

Honda EU1000 120 volt or EU10 240 volt. In this way, the battery takes the big pulse of

current draw, and the small charger replenishes the battery slowly. Therefore, you can

have a small generator.

 

2. Use a high-end flash pack which is transformerless. These are called by techs as

"capacitor multipler" units. Use only "perfect sine wave" type generators that have noise

and spike protection such as Honda's EU3000si or EU2000 (120 volt) which uses inverter

technology to make the electricity "more pure" like household AC current.

 

3. Cheapest way: Use a low-end transformer flash pack such as a Speedotron Brownline

or Norman 450volt or 500volt pack. The transformer will accept ragged sine wave output

which is generated by cheap industrial generators. The limitation here is that the heads

usually are limited to about 400ws of flash output apiece. The packs are usually steel

clad, too.

 

4. Maybe the cheapest way: Use Norman 200b's or Lumedyne flash units which are

used. These rely upon batteries, but can be hooked via custom cable to a larger car

battery. You could put these in an array to get more than 200ws. Connect them to trigger

using household cord or use a slave.

 

5. Inverter: These come in cheaper square wave units and much more expensive "perfect

square wave units". The batteries have to be huge, and you may need several batteries to

do the job. To see a larger inverter go to: www.kinoflo.com

 

Remember that the flash packs which can be switched to "slow recycle" are more valuable

to you because they require a smaller generator or power source. Examples of:

Speedotron Blackline units.

 

Maybe just borrowing someone's power AC through using a long, long cord may be an

option.