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(I'm a begineer in electrical stuff).

My wife needs a transformer for a leather electric creaser.

The transformers sold on the market are ridiculously overpriced (more than 250€). I don't understand why. Here are the specs of one of them :

 1 LV output with 0V to 16V electronic controller. 3A 48VA. 

What's so complicated/expensive in such a device ? How can I build one myself ?

UPDATE :

  • Here is a link to the product. Can't find another more precise spec. (Constructor does not even have a site...)

  • From a competitor product, I can tell it's an AC output (sorry it's a page in french). This one is 1.8VAC to 20VAC, 50VA power

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    \$\begingroup\$ Because people pay the money for those things because they think it is special and just needed for their leather stuff. Buy a lab power supply that meets the spec for a fraction of the cost. \$\endgroup\$ – PlasmaHH Jan 14 '16 at 16:43
  • \$\begingroup\$ All you need is any variable power supply that can put out 16Volts at 3Amperes. That's what that one is rated for. A quick look around ebay turns up lots of them for under 100Eur. I even find some on Amazon at reasonable prices (under US$50) \$\endgroup\$ – JRE Jan 14 '16 at 17:11
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    \$\begingroup\$ Be careful with terminology. 'Transformer' suggests an AC (alternating current) output. The specification sounds like variable voltage DC (direct current). \$\endgroup\$ – Transistor Jan 14 '16 at 17:22
  • \$\begingroup\$ You've posted a link to a photo. We need a link to a specification. \$\endgroup\$ – Transistor Jan 14 '16 at 18:46
  • \$\begingroup\$ @transistor, cf my update in the question. Pretty sure it's AC output. \$\endgroup\$ – Mathieu Jan 14 '16 at 21:21
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Buy a switching power supply- a good brand such as Meanwell so you don't create a safety hazard. Something like the RS-50-15, and crank the pot up to get 16VDC at the output.

Buy a Chinese DC dimmer 12-24V. The rating should be 8A (don't believe it).

Wire the two together in an appropriate grounded enclosure, and voilà, done.

Total cost should be about USD 20 plus case, power cord, fuse and switch.

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    \$\begingroup\$ Exactly what I did. Meanwell RS-50-15, a PWM, case, fuse and switch. Works well. The only (and small) defect is that the PWM induces a small hissing sound at the heating tool (probably because it's build with a coil, making it vibrate). But it's tolerable. Thanks for the advice ! \$\endgroup\$ – Mathieu Mar 14 '16 at 13:01
  • \$\begingroup\$ @Mathieu Thanks for the feedback. The hissing could probably be removed with an LC + diode filter, but I doubt it's worth it. \$\endgroup\$ – Spehro Pefhany Mar 14 '16 at 13:17
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If its fixed ac input variable ac output --you want a variac. They can be had on Ebay for pretty cheap ($50). Variacs are expensive because the dial connects to a brush that touches the windings -- not worth building IMHO. They are useful for all sorts of stuff. I use them to bringing up my power circuits slowly so I do not blow them all up. I also use them for heating a hot knife used for cutting foam (similar application as yours). That is about as cheap as you are going to get for a controlled heating element ... no fancy electronics inside.

enter image description here

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It isn't that complicated to calculate and build a home made transformer. Check it out for this video: Build an electric transformer (DIY)

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    \$\begingroup\$ Wrong kind of transformer. The OP used the wrong term. \$\endgroup\$ – DerStrom8 Jan 14 '16 at 20:03
  • \$\begingroup\$ @derstrom: what term is wrong ? \$\endgroup\$ – Mathieu Jan 14 '16 at 21:23
  • \$\begingroup\$ OP requires adjustable voltage. Your video link is fixed voltage. \$\endgroup\$ – Transistor Jan 14 '16 at 21:29

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