I made a wood burning machine out of transformers


#1

If anyone wants to not hurt themselves I can bring it down.


#2

Hi Ian:

I would love to see this in action. Do you have any photos of your build?

Also every Tuesday eve is open house from 7:30 till 10pm or so if you want to come down and show other people what you’ve made.

Check out VHS Events Calendar for the address info and other events.

Mark


#3

I didn’t take any pics, mainly because it’s dangerous. I might come by but
not for a little while, I’m out of town.
Seeing if anyone is interested was the point.

Ian


#4

How many transformers? Did you modify them at all?


#5

Two is what was recommended, my big worry was different voltage via
different windings, but since they are in opposite phase and the case is
the ground, I connected the two cases. It looks like you went down for a
spot Welder. I don’t see how the amperage can be controlled.

Ian


#6

The output amperage is controlled via the input voltage. In the short term I’m, using my PWM unit until I can figure out a built in unit.


#7

Actually I need to research and then build a variac


#8

Lee’s electronic had a suggestion, I was talking to adien,


#9

I’m being told to ‘leave it’, will just use good old hand timing to regulate. But before I do that I will see what happens when you put a PWM on the input side…


#10

Extremely dangerous. 4kv at 100mA is strong enough that you will never know that there was an accident.

I stopped working on mine when I realized that since the high voltage is referenced to ground I needed a way to prevent high voltage from accidentally entering the AC primary and flow into the AC network. The source of the transformers being “retired” microwaves that may have had arcing that damaged the transformer insulation made me rethink my safety protocols.


#11

Best to step them down instead. If you are going to handle something like that you would want to ensure that you were insulated with gloves and boots.


#12

While it’s true, working with live 4KV microwave transformers is potentially lethal, the one pictured above has had the high voltage secondary windings completely removed, and replaced with a big fat low voltage secondary. The secondary output is probably under 3 volts now. Of course, the 120V primary is still of significant concern, as always.


#13

I was going to hook it up to the ground, that won’t work?


#14

The modified transformer shown is mine and for a spot welder I’m building, Ian’s project has the transformers in tact I believe and still producing high voltages.


#15

Is there some diode you could use a a ‘one way valve’ or check gate to prevent the leakage?


#16

I just read up on capacitors, seems they block DC or keep it flowing in one direction and allow AC to pass unhindered. Could the appropriate capacitor be placed in line with ground and be used to prevent the back flow of AC power?


#17

The capacitor stores juice in a magnetic field, it can provide stability I understand (but can be wrong here) so only for DC. For AC it’s funny but again how I remember it was there is a neutral and a hot something to do with one wire on the windings the other on the housing or magnetic (feel free to correct me) the ‘ground’ third plug is to cases and whatever can provide an easier ground than hurting the equipment or people and pets, children with forks and a curiosity. Goes to the outside of the electrical box and there it’s kindof optional in theory to a copper rod 11feet in The ground or something. The volts are looking for the easiest was to each other more of a gradient or doffence more push or drive to do so, it feels it’s polar opposite via the megnetic field, you are conductive and it might find between your left and right hand the way to go, not the wood to burn or metal to arc out on. (Stories are involved here but leaving those put) one thing that always bothers me is irrational fear. Respecting safety and understanding is good, but respecting common sense and being aware is normally enough. Have one hand in your pocket and standing on something insulated and having the item you are on insulated and no distractions should be enough, not posting pics of it is my civic responsibility). I have a clip on one side and an insulated voltmeter probe on the other, no exposed wires. I’d like to show it off next week if anyone wants to see.


#18

yep, I do


#19

Ok, Bring something to burn! I have some scrap for practice. Next Tuesday 6:30 is the open night?


#20

There should be some wood scraps at VHS.

FYI Open house officially begins at 7:30 but somebody may be there at 6:30.

Mark