2017 - ITTSB project: Assembly of a Variac Powerstat 226U

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Kiriakos GR:
2017 - ITTSB project: Assembly of a Variac with Powerstat 226U transformer

Variac transformer (Variable transformer) this is one of the most useful devices ever produced for the smooth, distortion-less adjustment of AC voltage and power, with innumerable uses in testing and in control of voltage dependent parameters - speed, lighting, heat, etc.

Over the years Variac transformer assembly in a box (metal enclosure) this become a challenge and at the same time source of inspiration for thousands of people.
While transformer shape this is unchangeable, there is lots of room for product design improvising, speaking of shape and dimensions.

You can add to it items as for example panel meters, switches, fuses, power sockets, and even carrying handle.

ITTSB Blog within 2017 and me in person I got in to a new challenge, assembly of Variable transformer it is always a huge challenge if you think of it seriously.
My choice is a transformer capable for 2100VA (2.1 KVA) with voltage range from 0~270 ACV with input voltage of about 225~230V Mains voltage.

2.1 KVA this translates to seven ampere continues power, and this also translates that when you are thinking to order switches and fuses, you must do proper research and you to properly indentify true continues current specifications’ of its one component that you are planning to use.

Speaking of electrical switches product specifications’, for example I had to select one with name plate of 20A because this was capable for 7~8A nominal (3 Positions On-Off-On Changeover Control Rotary).

Purpose which this Variac is going to serve at ITTSB Blog
1) Testing of ups (Uninterruptible power supply) with supply of low or high input voltage, technically named as Boost & Trim ups condition (status).
One electrically healthy ups this it should respond by activating it inner circuit and electric relay, so this to compensate (adjust) it output and this be at acceptable range of around 230V.

2) Testing of any SMPS (switching mode power supply), inspection of output stability in all range of input voltage, for example this could be as 90~240ACV.

3) Motor Speed control, lighting tests and more…

4) Power supply for testing of active ACV stabilizers (thyristor based ones) or other type, and also for power quality evaluations.

ITTSB Blog 2017 Variac transformer project details
I did all my homework speaking of product design and parts list that I am going to use, I was forced to order parts from several countries.
Many of my parts are in shipping mode, and some others are still in manufacturing stage.

In this thread I am going to attach pictures of arrived goods and quick tests. ;)

Kiriakos GR:
My selection of parts regarding fuses, this was made also by the primary concept of my Variac project, and this is selection of ultimate quality parts, no matter their price.

Schurter FPG1 fuse holder this is great example of top quality part for panel mounting, connectivity this is made by clips.
Rich product specifications and several approvals.
www.schurterinc.com/pdf/english/typ_FPG1.pdf

For fuses I made a choice of SIBA 173100.8A slow-blow 5x20
www.siba-fuses

Kiriakos GR:
BERKER SCHUKO socket outlet ( MOBIL R series) this is also a product that does not come cheaply.
My opinion this is that recent pricing of BERKER products, it is extreme, either way I got lucky by finding old stock (production of W.Germany) in pristine condition.
Nowadays BERKER old MOBIL R series this now described as BERKER INTEGRO Series.

This product series qualifying for mobile applications, as for example boats, and laboratory equipment.

My VARIAC this will have double SCHUKO socket outlets, its one fused separately.
And also voltage output due isolated banana sockets, for voltage measurements by external multimeter.

http://www.elisch.cz/wp-content/uploads/2015/08/berker_serie_integro_mobilrtwin.pdf

giorgos:
I agree with you regarding quality of Berker products.
By the way, I have use Berker socket too, mounted in a distribution cable channel, in front of my workbench.