5
   

Difference between the 2 transformers

 
 
Reply Sat 27 Jul, 2013 11:30 pm
What is the difference between the traditional iron-core neon sign transformer which weighs up to 20KG and the *newer* and a lot smaller transformer which weigh more less about 1KG

I need the transformer as my power supply for my tesla coil, I need it to arc continuously and be able to charge my capacitor bank relatively quickly

Thanks in advance. I'll appreciate it. -cheers
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Type: Question • Score: 5 • Views: 1,282 • Replies: 11
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View best answer, chosen by andy8800
cherrie
 
  1  
Reply Sat 27 Jul, 2013 11:33 pm
@andy8800,
About 19kg.
andy8800
 
  1  
Reply Sat 27 Jul, 2013 11:35 pm
@cherrie,
Haha, you got me there.

seriously, stop fooling around. its kinda a headache for quite a while now
0 Replies
 
contrex
  Selected Answer
 
  2  
Reply Sun 28 Jul, 2013 01:32 am
Older neon sign transformers are just that - iron-cored transformers, usually embedded in asphalt to reduce noise. The core has a magnetic shunt which serves to current-limit the output, allowing them to run indefinitely in short-circuit conditions. They can also run indefinitely with no load. Iron cored varieties are quite heavy, for example a 15 kV, 60 mA device may weigh up to 20 kg.

However, since the 1990s, manufacturers have been producing switch mode power supplies to power neon signs. These generate the same voltage and current ranges as iron cored transformers, but in much smaller, lighter designs at high frequency (not the common 50–60 Hz). They are gradually replacing iron cored transformers in neon signs.

Plenty of coilers use solid state HV sources inclusing SMPS and flyback designs.
andy8800
 
  1  
Reply Sun 28 Jul, 2013 02:20 am
@contrex,
So does that mean SMPS won't work since they are operating at about 30KHz(according to SMPS for sale at ebay)?

contrex
 
  1  
Reply Sun 28 Jul, 2013 02:37 am
@andy8800,
andy8800 wrote:

So does that mean SMPS won't work since they are operating at about 30KHz(according to SMPS for sale at ebay)?




Read my post.

I wrote:
Plenty of coilers use solid state HV sources inclusing SMPS and flyback designs.

0 Replies
 
contrex
 
  1  
Reply Sun 28 Jul, 2013 02:40 am
IMPORTANT: Do you really think you should be fooling around with lethal voltages if you are designing your set up with the minimal knowledge that this thread reveals?
andy8800
 
  1  
Reply Sun 28 Jul, 2013 03:12 am
@contrex,
I know those are dangerous stuff, and yes I do have minimal knowledge about tesla coil designs right now, but do you honestly think that a person knows something without starting from zero?
well that is what I'm doing right now.

Thank for your answers dude -andy
BillRM
 
  0  
Reply Sun 28 Jul, 2013 03:42 am
@andy8800,
Quote:


https://en.wikipedia.org/wiki/Neon-sign_transformer


A neon-sign transformer (NST) is a transformer made for the purpose of powering a neon sign. They convert line voltage from the 120-347 V range up to high voltages, usually in the range of 2 to 15 kV. Most of these transformers generate between 30 - 120 mA.

Types[edit]

Older NSTs are simply iron-cored transformers, usually embedded in asphalt to reduce noise. The core has a magnetic shunt which serves to current-limit the output, allowing them to run indefinitely in short-circuit conditions. They can also run indefinitely with no load. Iron cored varieties are quite heavy, for example a 15 kV, 60 mA device may weigh up to 20 kg.

Since the 1990s, manufacturers have been producing switch mode power supplies to power neon signs. These generate the same voltage and current ranges as iron cored transformers, but in much smaller, lighter designs at high frequency (not the common 50–60 Hz). They are gradually replacing iron cored transformers in neon signs.

All NST's are designed to produce a high voltage starting pulse to a tube, then limit the current through the tube when it has started.This is opposite of most line transformers, which will produce full voltage to a load even if overloaded, unless the resistance of windings is too great to allow the excess current or until a winding burns out.

Other uses[edit]

Besides the obvious purpose of powering neon signs, iron cored NST's are often used by hobbyists for:

Tesla coil power supplies – used in small to medium sized tesla coils as the main source of high voltage.
Jacob's Ladder – a climbing arc device often pictured in older horror films.
Charging Capacitors – an NST makes a useful high voltage power supply to charge high voltage capacitors. Although the output of an NST is AC, it can be rectified by the proper diode or bridge rectifier.
.
0 Replies
 
BillRM
 
  0  
Reply Sun 28 Jul, 2013 03:53 am
@andy8800,
Quote:


http://www.personal.psu.edu/sdb229/TCTransformers.html

Somtimes OBITs and NSTs are solid state transformers, they basically work like a miniature tesla coil themselves, they operate at a high frequency to get higher voltage, so they cannot charge capacitors correctly (unless they are rectified and used in a DC coil, but that is a "whole 'nother ball game"). The rule of thumb is if it is really light and small and encased in plastic, it will not work. A regular transformer takes up a lot of space, and is alost always in a metal case, and will have a ground screw attached to it somwhere. If it is one of these seen below, you are good to go.
0 Replies
 
contrex
 
  2  
Reply Sun 28 Jul, 2013 04:02 am
@andy8800,
andy8800 wrote:
I know those are dangerous stuff, and yes I do have minimal knowledge about tesla coil designs right now, but do you honestly think that a person knows something without starting from zero?


I'm not trying to put you down; it's just that while what you don't know about some things can waste your time, or cost you money, or make you look silly, what you don't know about high voltage electricity can kill you or someone else, and with Tesla coils high frequency discharges (streamers) can cause RF burns (very bad!), can arc to an exposed 110v or HV transformer terminal (and then to you!), or destroy all the electronics in your house, (what will your parents or their insurers say about that?) ignite gasoline in your garage, start a fire, and so on. They are VERY noisy. They produce X-rays. There is legal stuff to consider. You need to be knowledgeable, careful, methodical and alert before you even start. If you try to learn "on the job" you could get bitten. Badly. You may know all this already, in which case I apologise, but it worries me that you are asking about coiling on a general purpose forum like this where any ignorant schmuck can come in and tell you all kinds of bullshit. There are specialist coilers forums where you can read and learn a great deal. Google will find you plenty, here's just one (you should research widely!)

http://www.teslauniverse.com/community/forums/tesla-builders/tesla-coils-and-high-voltage/0

This is a good site

http://www.pupman.com/


Safety notes

http://scipp.ucsc.edu/edu/tesla/teslacoil/safety.html


This is a very good safety page (I suggest you read this one. The tone and attitude it contains indicates how seriously you should be taking this):

http://www.pupman.com/safety.htm#contents

Good luck!


andy8800
 
  1  
Reply Sun 28 Jul, 2013 08:13 am
@contrex,
Thanks for the added information. yes, i know about the risks involving tesla coils, thats why I'm going to start with a electric fly swatter powered one. it is more of a toy than tesla coil but it will help me familiarize with possible problems and from there i'll inch forward to a more powerful tesla
0 Replies
 
 

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