Robert Nichols wrote:
On 3/24/20 3:10 PM, Clare Snyder wrote:
On Tue, 24 Mar 2020 09:14:40 -0700, wrote:
On Tue, 24 Mar 2020 00:26:44 -0700 (PDT), whit3rd
wrote:
On Tuesday, March 17, 2020 at 11:06:10 AM UTC-7, wrote:
On Sat, 14 Mar 2020 21:25:20 +0000 (UTC), Cydrome Leader
The alnico
magnets in old and/or inexpensive mag bases were/are magnetized after
assembly. This takes a LOT of current. I have seen the setups for
doing this and they are not trivial.
There's a two-part magnetization process for alnico, you have to observe the
built-in (at ceramic-firing time) polarity when you apply current.
It WILL magnetize one direction, not the other.
Usually, metalworkers have access to high DC current sources from Lincoln, Miller,
Hobart, etc. and that's what it'll take.
My 300 amp Miller would not provide enough current for decent
magnetization. Not even close.
Eric
Might work to charge the capacitor bank, but definitely won't do the
magnetizing unless you have a lot of turns - it's ampere turns that
make the feild strength - and too many turns increase the
inductance/reluctance and slow down both the build-up and collapse of
the feild.
The setups from some of the experimenters that use high-current pulses to
shrink coins might be a good place to start.
https://www.google.com/search?as_q=shrink+coin
Delivering 100,000 Amperes from capacitors charged to 12,000 Volts is a bit
of a challenge, though.
Not really. I've successfully done coin crushing and the setup doesn't
need to be overly complex like all the junk on google. The hype about
specially crafted parts, bullet proof chambers etc. is pure puffery and
marketing bull****.
There probably isn't a need for a one-use solenoid for remagnetizing a mag
base though, or the energy levels needed to crush a coin.
I sold my can crushing capacitor bank, but have some other large can
electrolytics. They're not really special low ESR versions but might be
coaxed into limited pulse use. The required amp-turns remains a mystery
though.