Ultra-low-voltage coilgun: the most powerful coilgun with the least copper

Zhizhi uses a high-current inductor + an AWithZ U3 (650A/4.2V) as the power source for an ‘ultra-low-voltage coilgun’: clamped in a vise, projectile pushed in, fired by the spot-weld trigger, decent power with visible recoil; the improved version has a thicker coil and only needs a press, no sparks, but a larger gap makes it less efficient; ‘the most powerful coilgun with the least copper’

A high-current inductor, and a sudden thought — could it make a coilgun; clamp it in a vise to test; push in the projectile; the resistance is tiny so it needs a high-current source, which brought the spot welder to mind — mine peaks at 650A with an output of only 4.2V, and if it works this is an ultra-low-voltage coilgun; try it straight away, decent power, you can see the recoil; the improved version has a thicker coil and only needs a press, no sparks, push in the projectile and try, efficiency seems a bit lower because the gap is a bit big; back to the original — truly the most powerful coilgun with the least copper; see you next episode. Comments: go study engineering, hand-build god (3); only 3.7V? the instantaneous high current makes the field that pushes it (creator: spot welders are all 1S or 2S, mine is 1S); a 310V one only manages this much; bubble-tea straw as the rail, thin is the point; could a supercapacitor be the power source.

Outcome

Steps4 steps · click a frame to jump

1. 
   1. The idea of a coilgun from a high-current inductor; clamped in a vise

   This is a high-current inductor; could it make a coilgun; find a vise to clamp it for testing.

   00:02 – 00:14
2. 
   2. Tiny resistance needs high current → spot welder, 650A/4.2V, ultra-low voltage

   Push in the projectile; the resistance is tiny so it needs a high-current source; thought of the spot welder, max 650A, output only 4.2V; if it works, it’s an ultra-low-voltage coilgun.

   00:14 – 00:36
3. 
   3. Firing: decent power, with recoil

   Try it straight away; whoa, decent power; you can even see the recoil.

   00:36 – 00:42
4. 
   4. Improved version, thicker coil, press-only, no sparks; big gap, low efficiency; compared with the original

   Improvement: thicker coil, only needs a press, no sparks; push in the projectile, efficiency seems a bit lower because the gap is a bit big; back to the original, the most powerful coilgun with the least copper; see you next episode.

   00:43 – 01:00

Bill of materials

Creator’s tips

• A spot welder is a ready-made low-voltage high-current pulse source (1S/2S) 00:14
• A thicker coil with press-to-fire gives no sparks; a big gap reduces efficiency 00:43

Pitfalls

• The improved version has a big gap and low efficiency 00:50

Li-ion safety

• A coilgun has recoil and projectile hazards when fired; not what a spot welder is designed for 00:28

Quotes