I wrote: ... >>> If the thrust can be increased by increasing the gap distance, how large can >>> the gap be made? >> >> As large as you wish, but if you increase the gap you must also e.g. increase >> the voltage and the wire-to-wire spacing, the parameters are interdependent >> so >> you must calculate them in the right order (cf the multiwire-plane design >> guide).
Here is a "minimal maths" optimum lifter design procedure I have just derived from the guide's equations: GUIDE: -------- Reference design: At 1 kV/mm (the max we can do without arcing) the power consumption is 2 W per "gram" of thrust, and the required area is 0.0025 m^2 per g. Scaling rules: The W per g are proportional to the kV/mm, whereas the m^2 per g go as their inverse square. Wire: as thin as possible (0.1mm OK in most cases), wire-wire spacing = 1.3 times the gap length d (optimum value) EXAMPLE: --------------- We want to lift 50 g, and we choose a v/d of half the max value i.e. 0.5 kV/mm, namely v=25kV for a d=50mm gap, to save on power consumption (our color monitor is only 75W) 1/ Required power per g: 2 W * 0.5 = 1 W -> Consumed power for 50 g = 50 W 2/ Required area per g: 0.0025 m^2 / 0.5^2 = 0.01 m^2 -> Required area 0.50 m^2 3/ Wire-wire spacing: 1.3*50 mm = 65mm That's it. Questions/improvements/corrections welcome. Michel
