Lighting-Gallery.net
Lamps => Modern => Topic started by: WorldwideHIDCollectorUSA on March 06, 2021, 05:10:22 AM
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I wonder if running an electrodeless induction lamp at the proper arc voltage and current using magnetic ballasts will cause any harm to the lamp or the ballast?
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It won't even light as the driver is there to run the induction coils at HF and so ionize the argon and mercury vapor.
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I've always wondered about that! If you tell me how exactly to connect that electrodeless lamp (https://www.lighting-gallery.net/gallery/displayimage.php?pos=-159215) to a magnetic ballast (and where I need to add the parallel ignitor), then I'll test your idea and I'll let you know how it went :'-)
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A spark gap tesla coil circuit might work although it's not the most practical :).
https://www.loneoceans.com/labs/inductionheating/inductionheating2.jpg
https://www.loneoceans.com/labs/inductionheating/ (not mine)
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I've always wondered about that! If you tell me how exactly to connect that electrodeless lamp (https://www.lighting-gallery.net/gallery/displayimage.php?pos=-159215) to a magnetic ballast (and where I need to add the parallel ignitor), then I'll test your idea and I'll let you know how it went :'-)
It would indeed be quite a feat to hitch a sulphur lamp to any form of control gear!, but referring to induction lamps, they still need over 2 meg hertz to run the induction antenna, something you can’t get from conventional control gear
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As far as I know, the lowest frequency of commercial induction lamps lies around half a megahertz, still way higher than the operational frequency of standard magnetic ballasts...
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In theory it may run on 50Hz magnetic field, but it would kinda need the field to be a bit stronger. More towards nuke strength...
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Some electrodeless lamps work with a microwave oven magnetron, which runs at a duty frequency of 50 or 60Hz, but the actual frequency is 2.4GHz.
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Some electrodeless lamps work with a microwave oven magnetron, which runs at a duty frequency of 50 or 60Hz, but the actual frequency is 2.4GHz.
Microwave oven magnetron will make them flickery, because the magnetron is active only during one half cycle (that is how the ballasts for the magnetron use to be designed in the ovens)
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Microwave oven magnetron will make them flickery, because the magnetron is active only during one half cycle (that is how the ballasts for the magnetron use to be designed in the ovens)
Yes, magnetrons work at half cycle, because they need a voltage multiplier, which are the high voltage capacitor and a single diode. Although the flickering is not that bad. Once I approached a fluorescent tube to the microwaves, and the flicker is not noticeable, only when you move your eyes.
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Yes, magnetrons work at half cycle, because they need a voltage multiplier, which are the high voltage capacitor and a single diode. Although the flickering is not that bad. Once I approached a fluorescent tube to the microwaves, and the flicker is not noticeable, only when you move your eyes.
Well, many people complain like heck even with 100/120Hz flicker, the 50/60Hz just wont fly at all...
And it isn't that much because they woul need a multiplier, but because that arrangement is the cheapest way to feed them. And unlike the lighting, the heating in the oven does not care if it is flickery on 50/60Hz or not...
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Well, many people complain like heck even with 100/120Hz flicker, the 50/60Hz just wont fly at all...
And it isn't that much because they woul need a multiplier, but because that arrangement is the cheapest way to feed them. And unlike the lighting, the heating in the oven does not care if it is flickery on 50/60Hz or not...
That's in case someone makes a crude electrodeless lamp out of a normal microwave oven. I wonder if proper magnetron electrodeless lamps have a full bridge rectifier before the multiplier, for reduce the flickering, although adding diodes might affect the efficiency due to their voltage drop.
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That's in case someone makes a crude electrodeless lamp out of a normal microwave oven. I wonder if proper magnetron electrodeless lamps have a full bridge rectifier before the multiplier, for reduce the flickering, although adding diodes might affect the efficiency due to their voltage drop.
For lighting there would be no multiplier, but most likely a bridge rectifier.
But mainly the ballasting would be made in a different way: In ovens it is just the series capacitor, which forms the magnetron anode current regulation. Because of the bridge rectifier (that is my guess), most likely to me is a kind of HX transformer.
But the lighting would mainly need different magnetron, because the oven type are designed for 50% duty ratio, so electrically are rated for double power than they would withstand thermally. And just feeding lower current won't fly either: Magnetrons have their high efficiency only when operated at the designed fixed operating point. Any other and the efficiency goes south, so lowering the feed (so the oven magnetron would be able to work at both halfwaves) would mean significantly reduced output power in order to keep the losses the same as on the reated halfwave operation.
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@Medved what about two magnetrons running with their multimeter on the same transformer, one for each half cycle? Would it overload the transformer?
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@Medved what about two magnetrons running with their multimeter on the same transformer, one for each half cycle? Would it overload the transformer?
I guess the "multimeter" was a typo and it should have been "multiplier"
You mean connecting the second magnetron instead of the diode?
There will be two problems:
Each magnetron needs filament supply for its cathode. Having two magnetrons in antiparallel means you need two filament winding. So it would need a special transformer for just this reason.
Then there is the fact the RF output is always at anode potential. So having two magnetron would mean two RF assemblies, with 5kV between them. Not much usable.
And the fact you have a second magnetron means there is double the AC voltage drop across the contraption, so the transformer will not have sufficient OCV for that. So ahain it would need a special teansformer...
And I see no way how to combine the RF power from two magnetron operating alternatively into one common load (the discharge,...).
All above the last one could be solved by just using two transformers, each feeding its magnetron, with just the primaries vonnected in the opposite phase. But the last one will be a kind of show stopper. The thing is, the nonradiating magnetron will act as a resonant absorbtion device, attempting to suck into its resonator cavity all of the power the second magnetron is generating. And that would overload the oscillating magnetron so much it will lose all of its efficiency.