Transformer construction

[olly_whinnett]

i have mental health problems

 

[tavib]

yes you can
but a close ferrite core is prefered in place of bar because the magnetic field .... you know

 

[olly_whinnett]

I don't understand - what's a 'close ferrite core'? What exactly do I need?

Do I need a soft iron core?

Does the method I described above for the construction of a homemade transformer sound like it would work?

 

[Optikon]

I don't understand - what's a 'close ferrite core'? What exactly do I need?

Do I need a soft iron core?

Does the method I described above for the construction of a homemade transformer sound like it would work?

I think he meant "closed" core. Closed in the sense that the magnetic flux ideally remains contained within the magnetic material. A transformer can be viewed as a coupled inductor. If you are going to be winding your own parts, you need to be familiar with magnetics. Here is a link to read about winding your own parts.



If you wind your transformer on a single bar, think about the flux path, now if you replace your bar with a toroid, you will see that the flux remains inside core material.

Also, how you wind it will make a difference. If your volts per turn gets too high, adjacent windings may short together (breakdown).

Designing a transformer is not a trivial task. Material selection & operating points must be carefully analyzed or you will be let down when it doesn't work or it smokes.

If you want this forum to help you with the design, you'll have to specify input & output requirements (volts & current), frequency of operation, geometry constraints etc... we have no idea what you have in mind!

 

[Hero999]

What he means is a ferrite bar is designed to act as an aerial meaning most of the magnetic flux will be radiated away as electromagnetic radiation rather than induced to the secondary. You need closed ferrite core is designed to contain all the magnetic flux within it allowing it to be converted into an electric current in the secondary.

Winding a high voltage transformer isn't easy because the potential difference between neighboruing turns can spark through the enamel insulation on the wire. To avoid this wear gloves (to avoid contamination from moisture from your hands), and wind the coil in many layers rather than a few wide layers and you might also want to consider adding a layer of tape between each layer.

I think you should aim for 5kV maximum and then build a multiplier from high diodes and capacitors on the output.

No actually don't bother winding a transformer, use a mains transformer in reverse.

 

[chemelec]

Most Stun guns use a ferrite Rod simular to what he has.

Yes a Closed core is More Efficient, but when your looking at a Real Stun Gun, It is nearly Impossible to insulate the 50,000 or more volts from arcing to a Closed Core.

Here is one of my articles on Stun Guns and it shows a typical HV Output transformer. (Pulsed trigger Coil)

**broken link removed**

The 5KV Circuits with Multipliers can put out the High Voltage with a Tiny amount of continuous current. Almost Useless and No where near as effective as a Pulsed Trigger Coil, simular to what I have made.

The Pulses on a commerical Stun Gun are much Higher current and the Pulsing Frequency gives a Much more Penitrating effect.

Not that I really suggest Anyone Build or Use a Stun Gun.

I only did it to see if I could and How high of an output Icould get.
Those articles I presented are the Lower powered ones that I made.

 

[DigiTan]

I've been wondering about taser transformers also. What are some sources of closed iron ferrite cores? I've been looking for a ferrite ring to use in a similar transformer, but I have no idea of where to start looking. Searches weren't too helpful. Would a retailer call them ferrite rings or do these go by some other name?

 

[Optikon]

I've been wondering about taser transformers also. What are some sources of closed iron ferrite cores? I've been looking for a ferrite ring to use in a similar transformer, but I have no idea of where to start looking. Searches weren't too helpful. Would a retailer call them ferrite rings or do these go by some other name?

Toroids.

 

[DigiTan]

I Should probably be looking for power toroids then? The toriods from Digikey's and Allied's were more of the circuitboard variety (and pre-wound).