my profile | my password | search | faq & rules | forum home

» Film-Tech Forum ARCHIVE   » Operations   » Film Handlers' Forum   » Switching Pwr Supplies and Carbon Arcs

Author Topic: Switching Pwr Supplies and Carbon Arcs Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 07-28-2011 04:19 PM                        Can a typical Switching power supply be adapted to power a carbon arc, say a Peerless Magnarc? It is burning 80smps now, a little under 3600w. Can, say, a Strong Xetron supply be used to power the arc if a ballast resistance is inserted so as not to short the supply when striking the arc?  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 07-28-2011 07:41 PM                        Xenon volts are about 24 volts dc. Carbon voltages are 2 times higher for copper coated and about 65 volts for rotating. Louis  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 07-28-2011 10:44 PM                     Wow,no wonder why xenon is cheaper to operate. "Gennies" and tungar bulb rectifiers really gobbled up the line current real bad for less results.  |  IP: Logged Ken Lackner Phenomenal Film Handler Posts: 1907 From: Atlanta, GA, USA Registered: Sep 2001 posted 07-29-2011 06:35 AM                     quote: Frank Angel a Strong Xetron supply Was "Xetron" a typo?  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 07-29-2011 09:24 AM                       65 Volts? This must be open circuit and not under load. It has been a long time since I worked on lamps but I seem to remember 29 Volts across a running rotating 11mm carbons in a Stong Futura lamphouse. 29 Volts x 100 Amps = 2,900 Watts which sounds about right. There are a couple of systems running in the Bay Area I can check. I don't know of anyone who has attempted this modification.  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 07-29-2011 01:25 PM                        8mm and 7mm neg is 60-65 amps at 41 volts; 11mm is 115 amps at 63 volts. I am simplifying the infor from an old National Projector Carbon Bulletins binder. It HAS been a long time. Louis  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 07-29-2011 03:57 PM                     Seeing as how Strong switchers can barely handle Xenon bulbs reliably, what do you think the outcome of trying to strike a carbon's arc will be? And remember that Xenon supplies start off with a high open-circuit voltage.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 07-29-2011 09:12 PM                     You can arc weld with the output of a Krell Amplifier so it might work with a switcher if you have a correctly sized ballast resistor in series. I have also heard of running Xeon off of the old MG sets. That was pure DC. Mark  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 07-29-2011 09:14 PM                     I too have heard of running Xenon off of MG sets...once the bulb is lit it is supposedly going to last longer on MG output as the DC is more "pure".  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 07-30-2011 08:28 PM                        In the old days, when Christie had a xenon conversion for the Magnarc, they also offered a ballast for the MG set. Worked OK. We're working on a xenon power supply that is comprised of all those old Kelmar DC supplies in series parallel. Let's see: 5 amps, I'll need 16 to reach 80 amps. Then 3 sets of those to reach 25 volts. Not bad, 48. That's about the amount I have. louis  |  IP: Logged Robert Throop Master Film Handler Posts: 412 From: Vernon, NY USA Registered: Jun 99 posted 07-31-2011 12:40 PM                     Why not get a power supply designed for the job? There must be plenty of carbon arc rectifiers to be had.  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 07-31-2011 04:15 PM                        Because I am finding that lately in my older years, I tend to evaluate equipment based on what I can lift easily.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 07-31-2011 08:10 PM                     Seems like Louis is doing the same thing! Those Kelmar supplies only weigh in at about 5 pounds each. Hey, I only have two more DP-70 to remove from service then I'm through moving those...  |  IP: Logged

All times are Central (GMT -6:00)

Printer-friendly view of this topic

Hop To: Select a Forum: Category: Operations -------------------- Digital Cinema Forum Film Handlers' Forum Large Format Forum Ground Level Feature Info, Trailer Attachments & REAL Credit Offsets Category: Community -------------------- Film-Yak Film Handlers' Movie Reviews The Afterlife Bob Maar's Joke-A-Thon Category: Classified -------------------- Equipment and Supplies Wanted/For Sale Help Wanted/Seeking Employment Category: System -------------------- Software Beta Testing Forum

The Film-Tech Forums are designed for various members related to the cinema industry to express their opinions, viewpoints and testimonials on various products, services and events based upon speculation, personal knowledge and factual information through use, therefore all views represented here allow no liability upon the publishers of this web site and the owners of said views assume no liability for any ill will resulting from these postings. The posts made here are for educational as well as entertainment purposes and as such anyone viewing this portion of the website must accept these views as statements of the author of that opinion and agrees to release the authors from any and all liability.