Latest Can Crusher
Why yet another can crusher you ask? Although the last version
worked, it was very inconvenient to use, since the crushing coil had to
be removed from its frame every time a new can needed to be crushed.
This design eliminates that problem. I can even remove the can from
the coil while it is still warm.
The coil is wrapped around a cup holder shaped form made from a 6.25
" length of 3" OD X 2.75" ID polycarbonate tubing. The bottom end
of the form is closed with two 2.75" OD X 1/2" thick polycarbonate disks
epoxied in place. The lower disk is drilled and tapped to accept
the 3/8"-16 terminal of my pulse capacitors. The coil is ten turns
of PVC insulated 14 gauge stranded copper wire, terminated with crimp on
3/8" ring terminals and held in place with three split rings made from
3" OD X 2.75" ID polycarbonate tubing. The split rings are not epoxied
in place, allowing the coil to be freely adjusted in the vertical direction.
Here is a photo of the crusher coil set up on my pulse capacitors,
along with the triggered spark gap and ground, charging , trigger and measurement
connections.
A close up of the crusher coil.
A series of cans, crushed at 25, 30, 35 and 40 KV, respectively.
The coil has a measured inductance (L) of 11.2 microHenrys and the capacitor
bank a measured capacitance (C) of 1.488 microFarads. This implies
a discharge time (one quarter cycle of the oscillation frequency, which
is = 1/(2*pi*sqrt(LC))) of 6.4 microseconds. Stored energy (E = C*V2/2)
of 465, 670, 910 and 1190 Joules, respectively. Average power (Pav
= E/t) of 73, 105, 142 and 186 MegaWatts, respectively. And peak
coil currents (2*Pav/V) of 5800, 7000, 8100 and 9300 amps, respectively.
And here is a short, low resolution, video
of a can being crushed.