# Device to pulse Electricity.

• posted

Hard to explain what I want, but I will try. Just imagine 10 electro magnets all in a line and all I want to do is put charge into each electro magnet one after another, but to it really really fast, to where it is like pulseing alone the line, don't ask why I want to do this its just top secret :)

I would like a way to speed up the pulse and slow it down and even increase the power to the electro magnets, which I think is the easy part :)

I was just wondering if there was any of the shelf kits i could use to do this, even if they ar enot really for this purpose, which would be great as i am not any good with electonics, though if forced I think I would have to try :)

Thanks for any help.

/PS I would only be using 12 volts for this, and maybe 12 volts to each electro magnet later.

Byes.

• posted

What are you trying to make? A rail gun?

BTW, how fast is "really really fast"? It might help to have some specs.

• posted

How fast is it going? Is the time for each magnet the same?

Can you use relays? If not I think you may end up with a "solderless prototype board", a LM555 and a CD4017 driving perhaps some 2N3055s to switch the power.

• posted

That's OK, we know what you want to do. :-)

But you'll have to live with an unfortunate aspect of coils and magnetic fields. The field is proportional to the current, yes, OK, but sadly the current increases slowly due to the coil's inductance, dI/dt = V/L, which says to quickly get a high current in a coil you'll need to use a high voltage.

For example, we needed a 1T magnetic field. I made a small coil (you can hold it in your closed fist), using 27 turns of #8 litz wire, and it had only 13uH of inductance. Our 1T field required 1.5kA and because we wanted to get it in 25us, we had to apply 1.2kV to get the current to 1.5kA fast enough.

Even tho 1.2kV and 1.5kA are large numbers (equal to 1.8MW of peak power), our coil's magnetic field would probably not be very impressive for what you have in mind. So you may be looking at even bigger numbers.

BTW, working hard to get the magnetic field up to where you want it quickly is one thing, but to avoid ruining the whole effect, you have to quickly remove the field as well. That means reversing the voltage, e.g., from +1.2kV to -1.2kV, which could mean each switch has to handle 2.4kV - and this is painful! Thankfully there are tricks using expensive Maxwell pulse capacitors to solve or simplify this problem. But you're still talking about some pretty serious stuff!

• posted

Mr Hill is trying to tell you that you can kill yourself playing with stuff. Beware.

That being said, ordinary Ford starter solenoids are a reasonably cheap source of a fairly powerful 12V electromagnet. I found that ~300V stored in a 820uF cap when dumped into the coil from the solenoid would launch a computer case screw (2-56?) across the room. It could toss a jewelers screwdriver about 3 feet. Be sure to understand that if you dumped that into your body instead, it would likely launch you allot further than that. Even all the way to the morgue. I'm not kidding.

• posted

Use a PIC.

But all "top secret" projects are GUARANTEED to fail.

```--
Many thanks,

Don Lancaster                          voice phone: (928)428-4073```
• posted

Use a PIC.

But all "top secret" projects are GUARANTEED to fail.

```--
Many thanks,

Don Lancaster                          voice phone: (928)428-4073```
• posted

Use a PIC.

But all "top secret" projects are GUARANTEED to fail. Without exception.

```--
Many thanks,

Don Lancaster                          voice phone: (928)428-4073```
• posted

Use a PIC.

But all "top secret" projects are GUARANTEED to fail.

```--
Many thanks,

Don Lancaster                          voice phone: (928)428-4073```

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