Gas powered generators

Anybody here ever use a gas powered generator as a source of electricty to back up their flash set ups ?

I use them occassionally in field shoots. I like the Honda generators for being quiet. You need to ensure you have a means to protect your flash circuitry. Do you have a specific question?

I've always wondered about this also. I would guess a surge protector between the lights and the generator might work.

http://www.alibaba.com/showroom/Inverter_Generator.html

"You need to ensure you have a means to protect your flash circuitry."

 

Why would you need protection for you flash circuitry, don't these generators provide you with the same AC electricty you find in your home, or am I missing something ? The reason why I ask is that I would like to do allot of location portraiture. Right now I rely on a portable Norman pack with batteries that I have to charge for hours. In case these batteries fail, which they do often(I carry back ups) a generator might give me peace of mind.

Many flash power packs, or flash monolights were damaged by inapropriate power generator or power converter, so

protection advice is as much appropritae as it can be. Problem is that there is no protection other than providing

clean and undistorted pure sin wave AC to your flash that was designed to operate from AC sine wave signal.

 

Surge protectors may not be sufficient, in general, since they cannot protect or filter higher frequencies spikes that

could get through the rectifier and damage the flash capacitor. Though it is better to use surge protector than not at

all. Some of them are called Spike protectors, that would imply able to catch spikes, but in reality they may just

be sort of surge protectors.

 

In general, you cannot depend on surge protectors for the flash charging that is a quite unique device. Unique in a

sense with huge instant current initial short duration loading and low average power needed.

 

That huge istant need for current can sometimes overload momentarily a generator or conterter, and force it into

generation of other than pure sine wave shape voltage, even if the device is rated as pure siwe wave, but has

insufficient lower momentary power yield.

 

Flash capacitor is always loaded to the MAX voltage level of the applied rectified DC voltage. What it means that

any voltage spike, or higher frequency harmonic component, resultant of mechanical vibration of poor quality gas

powered AC generator, or imperfect or modfied sine wave generation or distorted shape of pure sine wave of a poor

quality or underpowered power converter.

Thanks for the advice Frank. Maybe those funky batteries are not so bad after all.

On a simple AC gas generator such as my 4kW Generac the governor controls the engines speed; its above over the nominal 3600 Rpm at no load; and below 3600 rom at full load; with the cycles varying from say 61 to 59 thru the no load to full load range. Mine puts out a decent sine wave, and has been used to power the TV; fridge, several computers, the laptop, my old Sunpak 611 strobes, a mess of different AC power tools and DC battery chargers; of course not all on at once. <BR><BR>Each leg is about 17 amps on the 240 plug; ie each leg is 120 with respct to neutral; ie the leg close to ground. Another generator is 2kW ; a dinky 2 cycle unit is 800 watts. All of these work well with my Icom 735 ham radio's AC to DC unit or computers. <BR><BR>Some AC generators have some high frequency hash on their sign wave output. Most electronic items fail on AC generators due to dumb operators; yes dumb folks. They create this jackleg settup; cords become unplugged or half way unpluged and their stuff gets fried. Thus then blame the generators; since whining is the in thing today. Thus generator makers have all these disclaimers to reduce the duffus factor; the dumming done of America.<BR><BR>A common failure is the 240 plug works its way out; the neutral is lost and floats. It this situation the sum of the two legs is still 240 volts; one leg might be 180; the other 60 volts for an unbalanced situation. Or it might be 220 and 20; or 80 and 160 etc. The same thing can happen on your house if you cut the neutral; but theses connections are less jackleg. <BR><BR>Other failure modes are fire while refueling a hot generator; shock due to lack of grounding; dying due to running the generator in a close space. Another failure is you have all this stuff plugged into the AC generator; OR YOUR HOUSE; and you unplug one giant plug connected to your temporay settup. "inductive stuff" still connected such as shop lights, motors causes a "load dump" that kicks back voltage into your pretty iMac, strobe, computer and it gets ruined. <BR><BR>In the generator case most blame the generator instead of the duffus DNA of the user. In the temporary backyard settup where you had this one giant cord to your house some might try suing the local power company with little luck. With say 8 shoplights of a large back of lamps with ballasts; the load dump can be 500 to 1000 volts if there are little dumb simple laods to aborb the surge. Thus a surge protector helps with the jackleg factor not due a generator; due to the poor settup.<BR><BR>On many threads on Photo.net some folks pop in and say AC generators put out square waves; they probably think lenses are square; baseballs are cubes too.<BR><BR>In hurricane areas some of us have sumemr homes with 8 to 16 kW generators that run off of natural gas; the unit comes on once a week for exercise; and has usually about a 1 litre engine thats real quiet. <BR><BR>

I'm not an expert on electricity Kelly, although I once took a basic correspondence course on how electricity works. I never finished that course by the way, but it was interesting.

 

Anyway a couple of months ago, I purchased a portable printer http://www.usa.canon.com/consumer/controller?act=ModelInfoAct&fcategoryid=117&modelid=11009 . The batteries for this printer cost about 150 bucks last time I looked. I'm not too keen on chargeable batteries, because of several embarrasing situations that occured while on location during a shoot.

 

Although I had charged the batteries all night, then checked them again in the morning for my 2 light set up, one or both of them would fail and I would have to go scrambling around looking for extras.

 

This is why I'm a little hesitant about purchasing chargeable batteries. I figured that maybe a Generator might solve the problem, but I certainly don't want to fry my equipment.