What is beneficial about Tesla magnifiers? / Tesla Coils / Forums

Forums

4hv.org :: Forums :: Tesla Coils

« Previous topic | Next topic »

What is beneficial about Tesla magnifiers?

1 2 next

Move Thread

LAN_403

Avi

Sun Aug 01 2010, 12:46PM

Registered Member #580 Joined: Mon Mar 12 2007, 03:17PM
Location: Melbourne, Australia
Posts: 410

Since you connect a small coil in a magnetic field in series with a larger coil out of the magnetic field, wouldn't it be more beneficial to just make the secondary slightly larger since the total inductance would increase in both cases, but you would have the entire coil in the magnetic field.

ScotchTapeLord

Sun Aug 01 2010, 02:13PM

Registered Member #1875 Joined: Sun Dec 21 2008, 06:36PM
Location:
Posts: 635

As I understand, the inductance of the secondary in a magnifier would be negligible compared to that of the tertiary. Therefore, the voltage rise in the secondary would too be negligible compared to that in the tertiary, allowing for higher coupling due to lower risk of flashover. The magnifier essentially tries to separate the mutual inductance from the actual resonant inductance, so the high voltage in the resonant inductance can be placed further from the primary.

Avi

Sun Aug 01 2010, 02:34PM

Registered Member #580 Joined: Mon Mar 12 2007, 03:17PM
Location: Melbourne, Australia
Posts: 410

wrote ...

Therefore, the voltage rise in the secondary would too be negligible compared to that in the tertiary, allowing for higher coupling due to lower risk of flashover.

lets imagine you used the same wire and former diameter for secondary and tertiary.
Wouldn't you have approximately the same voltage on each turn of the secondary regardless of if the tertiary was on top of it or not?

wrote ...

The magnifier essentially tries to separate the mutual inductance from the actual resonant inductance, so the high voltage in the resonant inductance can be placed further from the primary.

I'm a bit confused here, could you try to explain this again, possibly simplified or different wording?
I am pretty sure adding series inductors would have an effect on the total running frequency?

Coronafix

Sun Aug 01 2010, 11:54PM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

The idea of the tertiary is to have it stand alone so it can ring like a bell, therefore the inductance in the tertiary should be higher than the secondary. If the secondary inductance was higher, it would be like ringing a small bell with a sledge hammer, rather than ringing a large bell with a mallet. That is also why the tertiary is removed from the magnetic coupling, although Teslas patents never showed that, in fact he showed the 3 coils all coupled to one another.
The coupling between primary and secondary must be higher due to lack of resonant induction happening here. The tank circuit is tuned to the tertiary and not the primary. The primary/secondary is acting like a normal step up transformer and so losses are greater than in resonant action.

...

Mon Aug 02 2010, 12:30AM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

Another way to think of a magnifier coil is that the tertiary is a 'base fed' tesla coil, and the primary/secondary are simply an air cored matching transformer to match the impedance of your driver with the tertiary.

If you wanted to, you could think of any coil as a magnifier with the tertiary wound on the same former as the secondary, there is obviously very little effect from the primary on the top of the secondary, so wether it is directly on top of the bottom of the secondary or somewhere else is (for a rough approximation) irrelevant.

Your point is valid however that you could if you so desired set the tertiary directly on top of the secondary, however it usually is advantageous to place the tertiary a distance away from the primary/secondary to avoid issues such as flashover, and show off your mastery of RF design

Arcstarter

Mon Aug 02 2010, 01:39AM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

I guess Avi is just one of those guys that does not post often, but makes it count when he does.

Hell, you could use this technique in many ways, like getting really long sparks in a small room with some hidden unit. Call it cheating all you want, i call it "work smart not hard".

HVgeek

Mon Aug 02 2010, 10:48AM

Registered Member #2998 Joined: Tue Jul 13 2010, 08:34PM
Location: Swedish forests.
Posts: 26

We all know that resonance in TC:s is very important, and the magnifier system does indeed rid the secondary - primary coupling of unessecary resonant voltage. This allows for a much higher coupling factor between primary and secondary.

The key is to make the secondary having as low inductance as possible, so the resonant voltage will be neligable. Typical TC:s have a coupling factor of about 0.2 - 0.3 primary-secondary, but I've heard of magnifiers exceeding 0.6. I'll get back to you with the source on that.

teravolt

Mon Aug 02 2010, 07:42PM

Registered Member #195 Joined: Fri Feb 17 2006, 08:27PM
Location: Berkeley, ca.
Posts: 1111

as i undrstand the primary and secondary has to have the best coupling as pausible for efishency.
I have seen videos claim that magnefiers are more efishent and people like Steve Ward say that there is no advantag to them does anybody know.

HVgeek

Tue Aug 03 2010, 07:02AM

Registered Member #2998 Joined: Tue Jul 13 2010, 08:34PM
Location: Swedish forests.
Posts: 26

Well, in theory since a higher coupling is possible without risk of arcover, yes definately. As I understand it it also greatly increases the ammount of energy a given size coil can handle.

BTW i found a good page that explains this rather well.

http://www.stargazing.net/Astroman/Magnifier.html

I have no idea if it's reliable, but in theory it seems sound. A non-resonant air core transformer with high efficiency for energy transfer, and a resonator for voltage build-up... Both claims makes sense.

Avi

Tue Aug 03 2010, 09:12AM

Registered Member #580 Joined: Mon Mar 12 2007, 03:17PM
Location: Melbourne, Australia
Posts: 410

HVgeek wrote ...

This allows for a much higher coupling factor between primary and secondary.

So are you saying there is less voltage per turn on the secondary than if the secondary and tertiary were ontop of one another?

1 2 next

Moderator(s): Chris Russell, Noelle, Alex, Tesladownunder, Dave Marshall, Dave Billington, Bjørn, Steve Conner, Wolfram, Kizmo, Mads Barnkob