Why welding or big power supply don't use mosfet or IGBT at first place?

[GeniusPooh]

Why welding or big power supply don't use mosfet or IGBT at first place?

I know now. I can use small transformer if hertz is higher ..

But why they don't use switching chip at just in front of AC input?

I think It save a lot space and electricity.

and If so . Can I make palm size 10kw ac-dc power source?

 

[tpetar]

Why welding or big power supply don't use mosfet or IGBT at first place?

I know now. I can use small transformer if hertz is higher ..

But why they don't use switching chip at just in front of AC input?

I think It save a lot space and electricity.

and If so . Can I make palm size 10kw ac-dc power source?

You can buy welding inverter device at every corner, just as SMPS PSU, look PC power supply 1-2KW.

Switchers are expensive devices on higher currents, can be really Bhut Jollokia in pockets.

Transformer based psu are almost undestructable devices and life time of this kind of power supply cannot be compared with SMPS. Also transformer based gives fine voltage output, compared with SMPS which have lots of ripples and spikes, which request additional filtering.

Welding device transformer AC/DC 180A can be around 55kg (good intermitenca-copper wires-high quality) and Inverter welding device of 180A can be 10kg. For portable variant what will you choose?

Also price of product will be higher if you use switching technology for power supply/welding device, cost of production, also needs better technical support-service. Iron transformer is simple to build and use, its reliable.


Few examples:

Welding inverter 100A
http://danyk.cz/svar_en.html

High power adjustable switching power supply (SMPS) 3-60V 40A
http://danyk.cz/reg60v_en.html

Very high current power supply
http://danyk.cz/proud_en.html

 

[GeniusPooh]

Y
Welding inverter 100A
http://danyk.cz/svar_en.html

High power adjustable switching power supply (SMPS) 3-60V 40A
http://danyk.cz/reg60v_en.html

Very high current power supply
http://danyk.cz/proud_en.html

In your example why he end with big capacitor ?

I think if he use at end very fast switch . he don't need big capacitor at all?

Am I right?

 

[tpetar]

To filter voltage and keep ripples in some normal range.

What is definition of "fast"? :smile:



Read this article about SMPS psu:

Pulse supplies and converters I. - Overview of topologies switching power supplies (with galvanic isolation)
**broken link removed**

Pulse supplies and converters II. - Overview of topologies pulse inverters (without galvanic isolation)
**broken link removed**

Pulse supplies and converters III. - Protection of transistors and MOSFETs
**broken link removed**

 

[FvM]

Few examples:

Welding inverter 100A
http://danyk.cz/svar_en.html

High power adjustable switching power supply (SMPS) 3-60V 40A
http://danyk.cz/reg60v_en.html

Very high current power supply
http://danyk.cz/proud_en.html

A bit rusty but obviously working!