Regulated Powe supply 0-15V 25A

[simce]

tca785 application

I need to design power supply for galvanisation process of metal objects and it has to deliver 15V and up to 25A.
Any sugesstion is welcomed. I was thinking of linear regulator with few 2N3773 but if there is some more elegant solution please share it with me.
Simce

 

[flatulent]

tca785 application note

For this process, the voltage regulation is not needed. You could just make a transformer off the mains with a bridge rectifier and a simple shunt capacitor. Then make an auto transformer with taps to set the input voltage from the mains.

Your needs are very much like car battery chargers which you might find cheaper to buy.

 

[mrcube_ns]

tca 785 applications

flatulent is right.

I made electronic two galvanisation machines 0-15V 0-500A (0-1000A other one), I used 3 phase transormer from 3X380V to about 3X15V. On secundar I put 3 pulse bridge (3 thiristors and 3 diodes), and electronics to drive that bridge (with TCA785). You dont need to add some caps becouse galvanisation process is capacitor for himself.

In your case use 1 phase transofmer, 2 thytistors and 2 diodes and 1 TCA785 to drive whole thing.

Mr.Cube

 

[simce]

15v/25a

Can you please share your schematic with TCA or maybe you have application note or something else regarding TCA?
Simce

 

[mrcube_ns]

tca785 voltage stabilizer

No problem, but I dont have it here on work, I have to post it from my home.

Tip:
In pdf of TCA785 there are a lot of examples, so my project is very similar with one of examples in pdf.


Mr.Cube

 

[mrcube_ns]

tca785 app

One link to TCA785 pdf.


h t t p ://62.236.156.23/ideaport/d/tca785.pdf


Mr.Cube

 

[simce]

15v 25a power supply

Thank you for quick response. I find the datasheet but still i need some information about this design. I need information where to put these thiristors and how to power up TCA. From datasheet i saw an example but it uses ferrite coils, and you told me that you use classic transformer. Do you make phase controll of primar wounds or secundar? Please help me make this gadget for my proffesor so i can continue with faculty.
Simce

 

[simce]

schematic + power supply + tca785

I can wait if you can send me your schematic from your home.
Sime

 

[mrcube_ns]

0-15v/30a power supply

I need information where to put these thiristors and how to power up TCA.

In the begining I try to do regulation on primar of transformer with triacs (big voltage small current), but its very tricky on triger angle of 90 degrees, so I put regulations on secondary of transformer. I'll draw pic in paint to show you => pic1.

To power up TCA I used small transfomer (220V/15V 5W you could buy those transformer on many places), gratz, capacitors and stabilizer 7815.

From datasheet i saw an example but it uses ferrite coils, and you told me that you use classic transformer. Do you make phase controll of primar wounds or secundar?

Ferite coils calls impuls transformers and its specialy used for driving gate of thyristor, I used them becouse I need galvanic isolation, if you dont need galvanic isolation you can drive it directly with resistor and diode.
Main transformer is classic transformer of about 25kW. [/quote]

 

[simce]

shematic regulator 25a

Have you used any kind of current limitataion circuit? As i can see if i turn on thyristor on 90deg large current will flow through it!?
Would it be more simple to use simple phase regulator on the primar side with diac and triac? I'm wondering what is happening because i'll drive inductve load that is not easy to drive with phase controlled tiac or tyristor?

 

[mrcube_ns]

tca785 applications

Good question.

I put shunt in main current cable, and with op. amp I made negative feed back which hold current on specified value.

Second thing are fuses.

There are 1000 Amps so curent limit isnt that simple.

In one phase case regulation on primar size is possible but transformer is warmer (cutting voltage with triac makes a lot of harmonic distorsion so there are more losts in iron of transformer) than usualy so you need a little bigger transformer then usualy.


Mr.Cube

 

[simce]

0-15v 20 amp schematic

OK. I'm waiting for your schematic, and i think that all my questions are going to be solved.
Best Regards,
Simce

 

[mrcube_ns]

siemens six pulse rectifier schematics

I edited my last post while you send me an answer so pay attention.

Mr.Cube

 

[simce]

power supply tca 785

What are you doing when op.amp senses overcurrent? Do you decrease voltage (change phase when TCA turns tyristor?) so you got constant current?
How does galvanisation tank act? As accumulator (battery), capacitor, resistor???
Simce

 

[mrcube_ns]

tca785 aplication notes

What are you doing when op.amp senses overcurrent? Do you decrease voltage (change phase when TCA turns tyristor?) so you got constant current?

There are 2 op amps, one amplifie voltage from shunt, second works like adder so its add set value voltage with amplified voltage from shunt (which is inverting voltage op amp).

How does galvanisation tank act? As accumulator (battery), capacitor, resistor???

Like a huge capacitor.


Mr.Cube

 

[tryagain]

tca785,application,rectifier

0-25V/0-10A

 

[simce]

schematic diagram of 15v regulated power supply

I have similar supply, but i need simplier sulition, something like Mr.Cube mentioned. Also it has to be implse mode where i don' have much dissipation power on transistors.
First i thought of this kind of solution but i'll have a lot of heat on transistors, even if i use multiple secundars on transformer.
Here i'm waiting for Mr.Cube's solution, as hi promised.
Anyhow any solution is welcomed.
Simce

 

[simce]

application for tca785

Hi Mr.Cube,
What should be done when the "capacitor" is going to be charged to some level. Does it has to be discharged or?
Where i can find some information about this process, like how it is performed and anything else regarding this problem, so i can know with what kind of process i'm dealing!
Also if you have with you your schematic please share it with me. You can send it on my private address:
sime_mileski@yahoo.com
Sincerely,
Simce

 

[mrcube_ns]

tca 785 application notes

Galvanisation bath is proces where ions goes from one electroda to another and vice versa. So, it isn't capacitor completly but all bath have capacitance effect.

Sorry for schematic I forgot yesterday, I come home very late.

I promised to send sch so I will.

Mr.Cube

 

[simce]

application of tca785

OK. I have general idea how should all be done. Today i'll ask for apropriate semiconductors (tyristors, diodes and else) in our local electronic shops. I'll ask for 30A or more rated diodes and tyristors.
Simce