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Registered Member #1694
Joined: Sat Sept 13 2008, 09:13AM
Location: Australia
Posts: 108
hotcrazyfruit wrote ...
Camel wrote ...
hotcrazyfruit wrote ...
killah573 wrote ...
Barry wrote ...
Spacing the coils in various ways won't have any effect on each stage's timing. Instead, I recommend building subsequent coils with progressively lower inductance to achieve a shorter LC time constant, which has the desired effect of shorter pulses.
You still need to compensate for flux density in the projectile. The flux in the projectile has to drop far enough so that the flux from the next coil will not cause it to saturate. Unfortunately, optimizing this aspect of the coilgun usually requires trial and error, unless you have a full list of material specifications for your projectile. With even spacing between the coils, the projectile can saturate, depending on your input voltage and specific coil design. It might be possible to simulate all of this in FEMM.
saturation is a GOOD thing. it means the projectile is recieveig electormagnetism. th thing with saturation, is there is a limit to it. which is why people build multi stage guns, to allow the projectile to de-saturate, before you re-satureate it.
ummmm no, saturation is generally a bad thing. The less energy absorbed by the projectile, the more efficient your gun will be. Have a look at a hysteresis chart for soft iron. You'll see the gradient is steepest as low levels of applied force. The idea of building a multistage coilgun is to apply small amounts of energy, many times over. The overall effect is much higher velocities than an equivalent single stage gun (which would waste lots of energy due to hysteresis losses).
ahh, i geuss i learn somethign new every day. lol. thanks.
aaah, I don't think I explained that very well.
Basically, the ratio between magnetic field strength and lines of flux through the projectile is not linear. An efficient gun will have maximum lines of flux through the projectile for minimum field strength.
banned on 5/26/2009 Registered Member #1877
Joined: Mon Dec 22 2008, 02:03AM
Location:
Posts: 147
Camel wrote ...
hotcrazyfruit wrote ...
Camel wrote ...
hotcrazyfruit wrote ...
killah573 wrote ...
Barry wrote ...
Spacing the coils in various ways won't have any effect on each stage's timing. Instead, I recommend building subsequent coils with progressively lower inductance to achieve a shorter LC time constant, which has the desired effect of shorter pulses.
You still need to compensate for flux density in the projectile. The flux in the projectile has to drop far enough so that the flux from the next coil will not cause it to saturate. Unfortunately, optimizing this aspect of the coilgun usually requires trial and error, unless you have a full list of material specifications for your projectile. With even spacing between the coils, the projectile can saturate, depending on your input voltage and specific coil design. It might be possible to simulate all of this in FEMM.
saturation is a GOOD thing. it means the projectile is recieveig electormagnetism. th thing with saturation, is there is a limit to it. which is why people build multi stage guns, to allow the projectile to de-saturate, before you re-satureate it.
ummmm no, saturation is generally a bad thing. The less energy absorbed by the projectile, the more efficient your gun will be. Have a look at a hysteresis chart for soft iron. You'll see the gradient is steepest as low levels of applied force. The idea of building a multistage coilgun is to apply small amounts of energy, many times over. The overall effect is much higher velocities than an equivalent single stage gun (which would waste lots of energy due to hysteresis losses).
ahh, i geuss i learn somethign new every day. lol. thanks.
aaah, I don't think I explained that very well.
Basically, the ratio between magnetic field strength and lines of flux through the projectile is not linear. An efficient gun will have maximum lines of flux through the projectile for minimum field strength.
wow.that image really helps me visualize whats happening exactly when i hit the SCR switch. thanks again. lol
Registered Member #90
Joined: Thu Feb 09 2006, 02:44PM
Location: Seattle, Washington
Posts: 301
Next time can you click 'reply' instead of 'quote'? We don't need one-line "thanks" notes in the first place (private messages are good for that), and we really don't need to fill the thread with repeated quotes as if it were an e-mail digest of random threads.
Thanks, Barry To misquote Smokey the Bear: Only YOU can protect our forum's information density.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
Indeed. I'm locking this thread for the following reasons:
An all-time record depth of quote nesting. Oversized images. Use of the "xD" smiley. Two spelling mistakes in a three-letter word. Zero or possibly even slightly negative information density.
Hotcrazyfruit and rp181, please get your act together. (Edit: I made a mistake. rp181 did not even post in this thread. However I received similar complaints about the quality of his posts in other recent threads, so the warning should still stand.)
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Multi-Stage coilgun
