# Wiring a large Transformer

#### Istvan77

Joined Nov 3, 2022
8
I'm trying to wire my transformer to do some fractal burning but can't find any information on it searching the numbers on it. the side with 2 wires (5-6) I'm assuming are positive and negative but I have no idea what to do with the 4 on the other side (1-4). Any help would be appreciated!

Joined Jul 18, 2013
27,021
See if you can tell the most innermost windings, i.e. the ones that were wound on first, this is usually the primary supply/power input connections. 5&6 maybe?

#### Istvan77

Joined Nov 3, 2022
8
See if you can tell the most innermost windings, i.e. the ones that were wound on first, this is usually the primary supply/power input connections. 5&6 maybe?
Not a clue but I think that's right but how to I connect 1-4?

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#### LowQCab

Joined Nov 6, 2012
3,069
Get an Exacto-Knife and carefully cut back the Paper-Outer-Wrap-Layers near the Terminals
so that You can at least determine what the Wire-Gauge is at each particular Terminal.
Measure the Wires with a Vernier-Caliper, record the number,
then find a conversion Chart that will tell You what the Wire Gauge is.
Some Countries just use the Wire-Cross-Sectional dimension in Millimetres, instead of the "Gauge-System".

This can help to determine the designed Voltage differences between the various Windings.

The smaller Gauge Windings will almost always be the Primary, or, "Higher-Voltage", Windings.
( I qualify this statement because I don't know if the Transformer
will be used to Step-Up-Voltage, or Step-it-Down, it could do either one ).

Regardless of how it's used, You should never exceed the Amperage-Rating of any Wire,
especially in a Transformer.

Once the smallest Gauge Winding is identified ..........
Use a ~60-Watt Incandescent-Light-Bulb, in series with the Winding, as a Current-Limiter,
and then connect Line-Voltage to the Winding/Bulb combination.
If the Light-Bulb does not light-up, or is really dim,
You have probably found the Mains-Voltage-Primary-Winding.
Now measure the Voltages at the remaining Terminals to see if they are useful to You.
Start-out with your Meter on it's "Highest-Voltage-Scale" so You don't smoke your Meter.
You really have no idea of what the Secondary-Voltages might be.
They "should be" less than Line-Voltage, if the Wire-Gauge on the remaining Windings is larger.

Shorting the Secondary-Windings together should make the Light-Bulb light-up brightly.
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Joined Jul 18, 2013
27,021
The size of those windings, it does not appear to be a mains fed version, but some other purpose. IMO.

#### shortbus

Joined Sep 30, 2009
9,861
I'm assuming are positive and negative but I have no idea what to do with the 4 on the other side (1-4). Any help would be appreciated!
When you say that, I'd say you need to do more research before going forward on your project. Not trying to be mean just trying to protect you. You don't seem to understand that a transformer is an AC not DC item.

And here is why I say I'm wanting to protect you - "Fractal burning, Lichtenberg burning or wood fracking refers to a technique where a Lichtenberg figure is burnt into wood using high voltage electricity.[1][2][3][4] It has gained notoriety due to numerous incidents of death or severe injuries when people have attempted it at home, with at least 33 people having died between 2017 and 2022." From - https://en.wikipedia.org/wiki/Fractal_burning

#### nsaspook

Joined Aug 27, 2009
11,271
I'm trying to wire my transformer to do some fractal burning but can't find any information on it searching the numbers on it. the side with 2 wires (5-6)View attachment 279888View attachment 279889View attachment 279890 I'm assuming are positive and negative but I have no idea what to do with the 4 on the other side (1-4). Any help would be appreciated!
https://www.woodturner.org/Woodturn...fety-Fractal-Burning-Lichtenburg-Burning.aspx
The AAW Board, through its Safety Committee, wants to re-emphasize the dangers associated with the process known as Lichtenberg, or “fractal,” burning, an embellishing technique that uses high-voltage electrical current to burn patterns on wood. This often unsafe, life-threatening practice has once again surfaced in the news and on social media, following a two-victim incident in April 2022.

In 2017, the AAW Board of Directors voted to ban any fractal-burning demonstrations and equipment sales at AAW-sponsored events. The ban prohibits displaying fractal-burned pieces at any AAW-sponsored event and promoting the practice via articles in AAW publications. Sadly, since the AAW Board adopted its policy on fractal burning in 2017, there have been thirty-three reported deaths directly attributed to fractal burning, and an unknown number of injuries and close calls.

#### Tonyr1084

Joined Sep 24, 2015
7,358
When I have an unknown transformer I start by using a transformer to drop line voltage down to 12 volts. Then using a meter I measure the voltage on other pins. Like @MaxHeadRoom suggested, I'd suspect pins 5 & 6 to be the primary winding since it is opposite to the other side. The four other wires are worth investigating BEFORE applying any voltage to it. Measure continuity between pins 1 & 2. Likely there is continuity. Then between 3 & 4. Likely there is continuity there as well. Then between 2 & 3. I suspect there may be no continuity. IF that is the case then the transformer suggests a single primary winding and two isolated secondary windings. If that's the case then it's likely that the voltage attained between pins 1 & 2 will be the same as 3 & 4. In that configuration the transformer can be wired for parallel output of (just picking numbers at random) 12V 4A, or wired in series by jumping pins 3 & 4 to produce 24V 2A.

Those numbers are just basic theory numbers. Transformers are not 100% efficient, so the numbers will vary a little bit, depending on how efficient the transformer is. And keep in mind, I made up those numbers. It is highly unlikely that those numbers would represent your actual results. But using a 12V transformer as a test voltage this will reduce the chance of unpleasant electrical shock. There IS a possibility you have a step-up transformer. More often than not they are used as step-down's. Microwave oven transformers are used by many a fool who want to burn wood the way you hope. And they are the ones you hear in statistics of people who've been injured. Or worse.

Be smart. Admire wood burnings from a safe distance. Unless you KNOW KNOW KNOW what you are doing and you FULLY UNDERSTAND THE DANGERS associated with it - do not attempt to recreate the effect at home. Your family probably wants you around for Christmas. Even Thanks Giving. Sorry to bang the gong of safety, but that's been part of my job at some of the places I've worked over the years. And I've seen industrial accidents. They're not pretty. Scenes I'll never forget.

#### shortbus

Joined Sep 30, 2009
9,861
When I have an unknown transformer
From his first post I'm thinking that he is just thinking, "my transformer is large, so it has to be high voltage".

@Istvan77, what is this transformer out of?

#### sagor

Joined Mar 10, 2019
829
When I have an unknown transformer I start by using a transformer to drop line voltage down to 12 volts. Then using a meter I measure the voltage on other pins. Like @MaxHeadRoom suggested, I'd suspect pins 5 & 6 to be the primary winding since it is opposite to the other side. The four other wires are worth investigating BEFORE applying any voltage to it. Measure continuity between pins 1 & 2. Likely there is continuity. Then between 3 & 4. Likely there is continuity there as well. Then between 2 & 3. I suspect there may be no continuity. IF that is the case then the transformer suggests a single primary winding and two isolated secondary windings. If that's the case then it's likely that the voltage attained between pins 1 & 2 will be the same as 3 & 4. In that configuration the transformer can be wired for parallel output of (just picking numbers at random) 12V 4A, or wired in series by jumping pins 3 & 4 to produce 24V 2A.

Those numbers are just basic theory numbers. Transformers are not 100% efficient, so the numbers will vary a little bit, depending on how efficient the transformer is. And keep in mind, I made up those numbers. It is highly unlikely that those numbers would represent your actual results. But using a 12V transformer as a test voltage this will reduce the chance of unpleasant electrical shock. There IS a possibility you have a step-up transformer. More often than not they are used as step-down's. Microwave oven transformers are used by many a fool who want to burn wood the way you hope. And they are the ones you hear in statistics of people who've been injured. Or worse.

Be smart. Admire wood burnings from a safe distance. Unless you KNOW KNOW KNOW what you are doing and you FULLY UNDERSTAND THE DANGERS associated with it - do not attempt to recreate the effect at home. Your family probably wants you around for Christmas. Even Thanks Giving. Sorry to bang the gong of safety, but that's been part of my job at some of the places I've worked over the years. And I've seen industrial accidents. They're not pretty. Scenes I'll never forget.
It might also be a split primary (120/240V) with a single secondary. Based on the numbering itself, I would have assumed 5-6 as secondary as it is higher in numbering...
But, without measuring, no way to know for sure.
I always use a 6.3VAC transformer to measure unknown power transformers...

#### Istvan77

Joined Nov 3, 2022
8
From his first post I'm thinking that he is just thinking, "my transformer is large, so it has to be high voltage".

@Istvan77, what is this transformer out of?
yes, you are correct. it came out of a magnetizer/de-magnetizer machine.

#### LowQCab

Joined Nov 6, 2012
3,069
That's not an indicator of it's probable Voltage-Ratio.
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#### Istvan77

Joined Nov 3, 2022
8
Ok everyone, I'm fully aware of the dangers and have made 2 before with much smaller transformers out of microwaves & it was much easier. Fractal burning is my only way to make a living at the moment so I'm just going to go for it, I have a family to support.

#### Istvan77

Joined Nov 3, 2022
8
UPDATE: I tested continuity between 5 & 6 and on the 200 ohms setting it was 1.1; between 1& 2 it was .04 and between 3 & 4 it was .04 as well. there was no continuity between 1 & 3 or 4 and 2 & 3 & 4.

#### LowQCab

Joined Nov 6, 2012
3,069
That sounds like 120-VAC Input with 2 - 24-VAC Outputs, at relatively high-Current.
Not what You need for High-Voltage.

A MOT is not a bad plan if you're extremely careful,
if you're not careful, even for an instant, You could wind-up dead.
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#### Istvan77

Joined Nov 3, 2022
8
That sounds like 120-VAC Input with 2 - 24-VAC Outputs, at relatively high-Current.
Not what You need for High-Voltage.

A MOT is not a bad plan if you're extremely careful,
if you're not careful, even for an instant, You could wind-up dead.
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.
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I understand and accept the risk but thank you for your concern. How would I wire that exactly?

#### Pyrex

Joined Feb 16, 2022
76
yes, you are correct. it came out of a magnetizer/de-magnetizer machine.
Can you tell us type of the machine ?
As i understand, the transformer is much bigger than the transformer in a microwave oven ?

#### DickCappels

Joined Aug 21, 2008
9,867
Where did the transformer come from?

#### MisterBill2

Joined Jan 23, 2018
14,698
I hope that you did not damage the transformer by hacking it up with a knife, that is a "very last resort" approach that might easily damage a thin wire connected to a terminal.
The transformer seems to be a low voltage output device, not suitable for drawing a high voltage spark. That is, assuming that the resistance readings are correct. But the wire size connected to the terminals does not agree with the apparent size of the transformer, because wattage IS related to size in transformers.
The wire sizes connected to terminals #1 and #4 appear to be much larger than the wires connected to terminals #2 and #3. Can you check the resistance between terminals #5 and #6 to the other terminals? The wire sizes do not seem to agree with the resistance and the size of the transformer.
The testing scheme suggested by Sagor in post#10 is a safe way to determine the ratio of the windings without risking damage or shock.
Are there other connections that we did not see??
Do you have access to the magnetizing machine that the transformer came from?
Can you give us the dimensions of the transformer??

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