Sorry, your question bounces around too much. Here's a lesson in electricity:
You have a 220 VAC lamp hooked to a transformer that converts 110 into 220. You state it is a 200 watt bulb. Here's how the numbers punch out: 200 watts divided by 220 volts equals 0.91 amps. If you were to replace the 200 watt, 230 lamp with a 200 watt, 130 v lamp and plugged it into regular 110 volt (more commonly considered to be 120 volts AC) here's what the numbers say: 200 watts divided by 120 volts equals 1.67 amps. But using a 120 volt light bulb won't require the use of the transformer. You'll draw one and two thirds amps which should not be any problems for the wiring inside the lamp, nor would it be too hard on the switch. The switch will break down sooner, but you're probably looking at 10 years service as opposed to maybe what would have been 40 years at the lower amperage.
Another lesson about Halogen lamps: They are made of a tungsten filament encapsulated in a glass tube filled with Halogen gas. That filament has resistance. Depending on the intended use they are designed with certain factors in mind. What voltage they will operate on and how many watts is expected of the bulb. If you want a 100 watt bulb at 120 volts then you have to calculate the amperage. That equates to 0,83 amps. Knowing the amperage the bulb will draw then tells you how much resistance the filament needs to be. Since Amps times Ohms (resistance) equals Voltage then Voltage divided by Amps (or ohms) equals Ohms (or amperage).
Since we know the amperage is 0.83 amps and the voltage is 120 then 120 divided by 0,83 equals 144.6 ohms. The tungsten wire has resistance measured in ohms per inch (or foot - I'm not sure). So suppose it's in inches and suppose it's 0.05 ohms per inch. The filament will need to be 2,892 inches long. If you look close at the bulb you see it's coiled. But if you look close at each coil you'll see they are made up of even smaller coils. That's how they get that much filament into a small bulb. It's a coil of coiled wire. And when the current flows through the coil it gets white hot, producing the light. Since the glass encapsulation (the bulb) is filled with Halogen the filament doesn't burn and disintegrate. Actually it does, but it does so by a process called sublimation. Atoms boil off the surface over time, which leads to the bulb burning out.
OK, what does all that have to do with your simple question? Not much I suppose. But understanding how a bulb works and its design you should be able to figure out for yourself whether an R7S rated at 120 volts will affect your lamp that was originally designed to operate at 240 volts.
The short answer is: Shouldn't hurt anything to run the lower voltage bulb. Sorry it took me so long to get to that.
Hope this helps.
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