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I need help with this circuit.

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gary350

Well-Known Member
How do I calculate the current being discharged from these 2 large blue Mallory capacitors 3" diameter 6" tall 74,000. uf each?

How can I put an indicator light on this so I know when capacitors are fully charged?

Can I use Mosfet or ??? in place of a push button switch. Switch self distructs pretty quick.

I plug this into the wall then wait about 60 seconds to make sure capacitors are fully charged through the 1n4007 diode and the current liminting resistor. I place an old round iron speaker magnet in the center of the coil then push the buttom to discharge both caps into the coil. The small magnet will lift 2500 lbs for 2 seconds.

Magnet has a half live of about 3 seconds. The magnet measures 5/8" diameter by 1/2" long. It will barely lift a 1 lbs block of steel but after being super charged it will lift 2500 lbs of steel and hold it for about 2 seconds. The super strong magnet looses it strength at a rate of about 1/2 every 3 seconds until the magnet is back to normal.

I dont know the maximum lifting power of this magnet. By the time I charge the magnet then use the hoist to lift the steel about 2 seconds magnet has probably lost 1 half life.

002_zpsvjb1tr8i.jpg


This is a dangerous circuit and should only be used by trained electrical professionals
 
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Mosaic

Well-Known Member
Magnets don't possess a half life. You're not dealing with radioactivity.
You're seeing evidence of the magnetic field collapse of the inductor, the magnetic field rises and falls over time, inductors resist current change.
The best way to determine the charge on the capacitors is to monitor their voltage.Q=CV.
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/capchg.html

This is a kind of coil gun you made.

Safety:
Gary, why are you playing with these industrial level voltages and currents when you don't understand the theory?
You can cause serious harm to yourself if things go wrong! That coil is going to generate serious inductive kickback upon collapse of the magnetic field. It's probably arcing across the switch. If it can't discharge somewhere it's going to make killer flyback voltages! You better not have a pacemaker and collect a zap from that coil!
 

alec_t

Well-Known Member
Most Helpful Member
A highly dangerous circuit, with no mains isolation and with LETHAL voltages :eek::eek:.
 

JimB

Super Moderator
Most Helpful Member
As drawn, your diode is the wrong way round.

JimB
 

cowboybob

Well-Known Member
Most Helpful Member
gary, that's one of the scariest circuits I've seen posted.

What's even scarier is that you've tested it!!
 

gary350

Well-Known Member
Magnets don't possess a half life. You're not dealing with radioactivity.
You're seeing evidence of the magnetic field collapse of the inductor, the magnetic field rises and falls over time, inductors resist current change.
The best way to determine the charge on the capacitors is to monitor their voltage.Q=CV.
http://hyperphysics.phy-astr.gsu.edu/hbase/electric/capchg.html

This is a kind of coil gun you made.

Safety:
Gary, why are you playing with these industrial level voltages and currents when you don't understand the theory?
You can cause serious harm to yourself if things go wrong! That coil is going to generate serious inductive kickback upon collapse of the magnetic field. It's probably arcing across the switch. If it can't discharge somewhere it's going to make killer flyback voltages! You better not have a pacemaker and collect a zap from that coil!


If you super charge a magnet that can lift 1 lb so it has the power to life 2500 lbs, then 2 seconds later power drops to 1250, then 2 seconds later it drops to 625 lbs. 2 seconds later it drops to 312 lbs, 2 seconds later it drops to 156 lbs, 2 seconds later it drops to 78 lbs, 2 seconds later it drops to 39.5 lbs, 2 seconds later it drops to 19 lbs, 2 seconds later it drops to 9.75 lbs, 2 seconds later it drops to 4.8 lbs, 2 seconds later it drops to 2.4 lbs, 2 seconds later it drops to 1.2 lbs, then back to normal 1 lb. That is called half life. They is what they call it on the Physics Forum. The actual words used on the physics forum is, a magnet has a half life of 2.5 seconds. OK so I left off the .5 just to make it easier to type.

Why are you not playing with things that are fun. If people did not play with things like this a lot of things would have never been invented.
 

Mosaic

Well-Known Member
Why are you not playing with things that are fun. If people did not play with things like this a lot of things would have never been invented.

One wonders if Madame Curie would have played with radioactivity in the manner she did without protection if she knew the potential outcome. I doubt it.

This might be a useful read based on your interest.
**broken link removed**fields/electromagnetism/414/file_46953.doc
 
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