I had an interesting thing happen the other day. While on a shoot I was setting up my Norman 20/20 with two lights. As I was taking flash meter readings I heard a loud bang. I looked at the power pack and heard another loud bang, saw the flash cord fly out of the pack and saw a three inch flame shoot out of the pack. The connections on the pack and the flash cord were cooked and fortunately I was not. Any ideas as to what happened or has anyone had this happen to them? Just another fun shooting experience. Ken
Moderately old NiCd batteries that haven't been deep cycled can develop metal dendrites that connect the electrodes and short the battery. This heats the electrolyte to the point of vaporization if the battery is full, and it ruptures. The expelled electrolyte, if it has a low enough potential, can then react with the oxygen and ignite.
Or else an explosive expert hates you.
I hope it's the former.
There are no NiCd batteries in a Norman 20/20 pack. This is an A/C strobe pack.
You blew a capacitor (or two). It's pretty alarming, but not unusual, and can happen with any strobe pack, particularly as they get older. A place like the Flash Clinic in New York (www.flashclinic.com) can replace the capacitors.
I once had a capacitor blow in a densitometer. This was even more strange, but the capacitors in densitometers are considerably smaller than the ones in studio strobe packs.
There was a saying I remember from a few years ago:
"Friends don't let friends buy Norman".
I've used them, never owned them. Never had any power pack blow up. Saw the results of a 3200 Speedotron blow up. Not Good.
Sounds like you got an arc in the plug. Sometimes that can happen if the plug isn't seated completely in the socket on the pack. I remember that it was essential to completely discharge the old Calumet packs before unplugging a head. If not, as soon as the plug was slightly unseated.... KABOOM!! The plug and socket are fried and the photographer jumps a out of his skin :(.
fwiw--we've had the same speedotron 2403 pack fry out the capacitors twice. Both times were fixed under warranty repair since the pack was only a couple of years old. We have a 2401 pack close to 15 years old and keeps on chugging away day in & out, but not this one...first time I was doing a couple of multiple pops in the studio--and a 102 head exploded and pretty much was fried out beyond repair--in turn the pack refused to recharge and got warm to the touch and sorta sat there buzzing and smelling like burnt toast. So off it went and same thing happened a year or so later, minus the exploding head, but this time the pack was just sitting there turned on and made a loud pop, got warm and that smell came back....again, off it went, now a couple of years later it still acts up now & then--refusing to discharge occasionally or the most bizarre is that it will leak a charge and cause the tubes to glow for 20-30 seconds....so, either it's possessed (possible, supposedly there's ghost in our building and the capitol next door is haunted so who knows?) or it's ready to go back to Chicago once again....btw--I've seen what happens with an arcing plug on a speedotron and this isn't what I'm talking about. The great thing about the company was the second repair was done for free even though we were out of warranty....there might have been some problems with that model, I really don't know, but it's never seemed to be as reliable as the older pack.
Electrolytic capacitors slowly degrade over time if they are not used regularily. They can be fixed by something called reforming (not convienient), or this problem can be avoided by powering up the pack for a .5 hour every month or so.
I *love* those "arc-proof" connectors in the DynaLites. I habitually shut them off and discharge them before connecting or dis-connecting, anyway, but it is nice to know that a minor transgression will not produce a three foot arc.
The other *great* idea, in my book, is the three-bladed synch connector. I shudder to think of the consequences of plugging a synch cord with a Hasselbald lens on the other end into "line" power, and the third blade prevents this, effectively. I'll *happily* go to Dynalite and pay the "big" money for these.
okay--look I work 40+ hrs a week in a studio...we use speedotrons (have 3 packs, actually getting ready to buy 2 more 2403cx's and 6 heads), we also have a half dozen or so totas/omnis, some softlighters etc. The speedo packs I mentioned get used every day. We haul 'em out on location, use them in the studio--even dragged outside occasionally. I'm using this lamented 2403cx now--for cross polarized copywork. It's on for 8-10+ hours a day sometimes , and we'll use every pack we have to do furniture sets or location work and do multiple pops until everything in the room is floating in front of your eyes....
as for dynalights--yeah, great packs--it's what I use for my own work. But I've never pulled a plug out without turning the pack off. Never plugged one in without it turned off either. I treat them just like Speedotrons for 2 reasons. One, I don't want to pull a bonehead move at work & kill myslef with an arcing pack. I worked as an assistant once in a stuidio where this guy had burned a hole in the wall by doing this and killed the power pack. Second, I don't trust it....sorrry, call me cynical, but that's alot of juice in the pack.
FWIW--the stuff I do at work? We do 8, 12, 16 pops sometimes and isolate packs to more or less pops as well. All 4x5 stuff with small apertures--you can never have enough power, and unfortunately Dynalites just don't cut it in a studio....great for the road, or headshots or hanging from rafters for ball games. Not so great for shooting mahogany furniture that's 7 feet talll by 12 feet wide with glass and marble all over the place...the best light for this is actually a studio full of 1K Mole Richardson fresnels, nooklites and mickey-moles....but we also can't afford to go out & refit completely. The speedos aren't fancy, but except for this one pack, man..they're rugged and a great value. You can get them serviced all over the place, and there's rental stuff to boot, plus the other studios in my system use them as well. . bottom line is that we're stuck using speedotrons for better or for worse...I like 'em personally and have thought many times of selling my Dynalights for a 2400 ws blackline kit.
I use to work as an assistant in NYC. Every single photographer that had Norman packs always had them blow up all the time. The first time I turned off a Norman pack it blew up on me with sparks flying out the side. I never trusted them since.
I've had a few Speedos and Dyna-Lite pop but worked with those packs for such a long time that it was a rarity.
Do what DKT mentioned about turning off power before changing plugs no matter what pack you are using.