Re: [Frameworks] AC/AC 1500W converter query
Not so much a response to this post... but to the previous lamp brightness post... I have a projector that uses a rheostat to up the voltage sent to an ELC lamp. It over drives the lamp voltage, but just slightly, say 24.5-25V. There is a point at which you can push the lamp near the breaking point. If sending too much voltage the lamp will blow... but just a little over 24V and you're increasing brightness without blowing the lamp. If it shortens the lamp life, I haven't noticed it. Not certain how this would work with the on-board transformer of a Eiki SSL or Kodak Pageant or whatever you're wanting to use, but if you have a machine to sacrifice, you might try a rheostat. There is also David's suggestion of the higher output ELC (more lumens), or the suggestion of a 2 blade shutter (if you currently have a three blade), and using a fast lens... most 38mm and wide angle lenses will be f1.5 or slower, but if using an Eiki with an ISCO 35-65, you get f1.3, or if you have a longer throw, a standard, large barrel 50mm lens is usually f1.2 (Eiki, Bell Howell, etc). Then, as others have mentioned, there is the gain (reflectivity) of the screen, and the darkness of the room. Image size can be another indicator of brightness, one needs to right size the image according to the power/efficiency of the light source available. With xenon lamp houses, a lot of time can be spent aligning/adjusting the lamp and lamp reflector for optimum efficiency... focusing every bit of light on the gate without spillover. Alain On Tue, May 13, 2014 at 11:47 AM, Alex MacKenzie alexgmacken...@gmail.comwrote: I picked up a power converter at at thrift store for $10 called a Patronics AC/AC Converter. It has input select 110 vs 220 and says 1500W max with ground lead. It is a black 7X7X4 inch (18X18X10 cm) brick of a thing, weighs about 25 pounds. What I am unclear on, is A) if it is working correctly, and B) if this is something I can use overseas in 220V land to run projectors. Will it take 220V input of power? When I plug a conventional desk lamp in (a device I am willing to risk!) with 60W bulb using 120V power (US/CAN standard) These are the results: without converter - standard light output with converter set to 110V - much much brighter with converter set to 220V - very dim I haven’t kept it on for an extended period, but do these results make sense? Of course, I don’t have 220V power handy, so I can’t test the power input end, though I could maybe try plugging it into a clothes dryer plug (220V) with a plug converter… At $10, no big deal if it is just a heavy useless brick, but it seemed worth looking into. Thanks to anyone who can shed some light (whatever brightness) on this situation. Here is a picture of it: http://www.alexmackenzie.ca/images/patronics.jpg Alex ___ FrameWorks mailing list FrameWorks@jonasmekasfilms.com https://mailman-mail5.webfaction.com/listinfo/frameworks -- 40 FRAMES Alain LeTourneau Pam Minty 40 FRAMES 5232 North Williams Avenue Portland, Oregon 97217 USA +1 503 231 6548 www.40frames.org www.16mmdirectory.org www.emptyquarterfilm.org ___ FrameWorks mailing list FrameWorks@jonasmekasfilms.com https://mailman-mail5.webfaction.com/listinfo/frameworks
Re: [Frameworks] AC/AC 1500W converter query
It is a black brick of a thing, weighs about 25 pounds. It's a transformer - basically two big coils of wire wrapped around an iron core. It has to be heavy to handle enough current to run various devices. What I am unclear on, is A) if it is working correctly, Based on your tests, yes. If the converter is set to 110V, then it's doubling the voltage, putting out 220V. If it's set to 220V, then it's going the other way and halving the voltage, in this case dropping the 110V to 55V. The voltage change in the transformer is by the ratio of the number of turns in the primary (input) coli to the number of turns in the secondary (outout) coil. B) if this is something I can use overseas in 220V land to run projectors. Will it take 220V input of power? not so simple a question. First, Voltage is not power. Power is measured in Watts. Wattage is the product of voltage (V) times current (A). Voltage is the 'push' determined by the power source. A 110V AC line pushes current through at 110V now matter how much current you use, a lot (say for a refrigerator) or a little, (say for a clock radio). Current - measures in Amps (a milliamp is 1/1000 of an Amp) is the pull determined by the device, the amount of actual electrons it draws through the wire to do whatever it is it does. Any power source can only supply so much current. That maximum is specified by the Wattage rating. So if you have a 1500W power source, at 110V is can deliver up to 13.6A before it hits it's ceiling. At 220V it can deliver up to 8.6A. But there's only ever as much current running through the wires as the device(s) attached to it demand. If a 110V clock radio draws 1A, and that's all that's connected to the 1500W source, it's only using 110W of power. If you have more than one device connected to a power source, the total current drawn is the sum of the current drawn from the various devices. Say you have a 110V outlet on a 15A circuit breaker. That will take 1650 Watts of devices before the breaker trips. Plug four 500W production lights onto that circuit, and 'pop' goes the breaker, as each light is trying to pull over 4.5A. So, the first question becomes what's the Amp rating on the projector? If the projector runs on 110V, as long as it draws less than 13.6A, the transformer will power it. E.g., a Pageant 250S draws less than 5A. And older projector with an AC incandescent lamp would draw more, but should still be well within the 1500W range. HOWEVER: Projectors determine their speed on the basis on the frequency of the AC current used to power them (listed in Hertz: Hz, which means 'cycles per second'.). The transformer just changes the voltage, not the Hz. A US projector is designed to run off 60Hz power. In Europe, house current is 50Hz. So if you plug your projector into the transformer, and plug the transformer into the wall in, say, the UK, instead of running at 24FPS it will run at 20FPS. Some projectors are designed in a way that they can be adjusted for the proper speed of the different cycles. This usually involves removing the cover and switching the belt to a different pulley. However, many projectors do not have this feature. Instead, changing the belt from one pulley to another determines whether they run at 'sound' or 'silent' speed. You can probably find info on the capabilities of your specific projector here: http://www.film-tech.com/warehouse/index.php?category=2#16mm%20Projectors ___ FrameWorks mailing list FrameWorks@jonasmekasfilms.com https://mailman-mail5.webfaction.com/listinfo/frameworks
