Hello this is my first post and thought to start with a project...

I have started and almost finish the PS i will present below
Main thought is to make the simplest circuit i could find and have a 10A power supply for my lab needs.

Any ideas or suggestions to make it better are welcome

Will start with circuit that is not mine design.

That was found at

http://www.radioaficion.com/HamNews/articles/1482-138-30-volt-10-30-amp-l200-power-supply.html

 

If you using this circuit, the power transistor are 2N3055, for the power consumption issue, so you better using 4 pcs of 2n3055, at least 3 pcs, and each 2n3055 needs to in series with a 0.2Ω/10W resistor.

 

No images...? Sorry
Maybe a moderator can erase the above post please

After a conversation I had with colleague Andreas about it...











To be continued...

 

Your attachments are wrong.

 

Bath time


Enough



Second bath with
ferric

 

If you using this circuit, the power transistor are 2N3055, for the power consumption issue, so you better using 4 pcs of 2n3055, at least 3 pcs, and each 2n3055 needs to in series with a 0.2Ω/10W resistor.

I have replaced the 2n3055 with MJ15003
It is far better as i know

 

And the resaults are very good !!!




polishing


Electroprojects


Drilling it...



Holes readyto insert parts

 

Mounting the transistors and parts at pcb



Ready

 

Time to gather all parts and connect them

Transformer:

 

Something i haven't done yet and must be done is to make the Transformer from 30-0-30 8A to 0-30 8A
Need to parallel the secondary so i can drain all amperage from 0-30

Any suggestions will be appreciated.

 

U can if you can isolate the center tap.
CT secondary are connected as follows.
30-0-30 --> Start A(30V)-End A joined with start B (0V)-End B (30V).
A and B are two secondary windings.
Disconnect End A and Start B ( which is Center tap )
Connect Start A and Start B together
Connect End A and End B together.

After you disconnect center tap you will have isolated secondary A and B windings. You will get 30VAC on each windings.
After paralleling them if you measure 30VAC on the secondary winding you are good to go.
Mind you if one winding can handle 8A you can draw max of 16Amps by paralleling them

 

By the way for huge currents, the smoothing cap needs to be 10,000uf or more.

And the Power should be taken directly from the capacitor terminals.
Not one from cap and one from bridge as shown in ur picture

PS. You should add fuses in primary and secondary. You are dealing with high currents

 

Is this what i must do ?
It is real simple i think but haven't opened a transformer before

 

my bench supply is similiar to this using lm317/337 mj15003/15004's

R!f@@ 's comment about fuses should be noted (read as a requirement - common sense)

edit: no need to 'open' the transformer, from the look of the picture, the two windings have already been soldered together on the 20v secondary side (centre wiring - 2 wires twisted and soldered) just need to break that connection and parallel up as per your diagram.

 

Fuse are in schedule from the beginning of this project
They will be added at the chassis when it will be ready... (pics of it are coming soon)

I will give it a shot with secondary of transformer this evening
Thanks for the advice

 

As said, you do not need to dismantle the whole TX.
The center tap is accessible easily. Just use the iron and untwist the secondary with pliers and you can connect as per ur diagram.

 

This is the old pc case that will be used/modified




New frontage

New frontage cuted...






drilled for the case..

 

I was thinking using the pc case button and make a little very very simple circuit for electronic switch with relay.
This is what i found with a quick search
http://www.electronics-tutorials.ws/blog/relay-switch-circuit.html



This needs extra power supply for vin

If anyone can suggest a very simple one it will be nice to share with me.

 

Power Supplies use toggle switches.
Safer and better.
I wonder why you need to use a relay.

Using that circuit requires the power applied to TX always. If this is not a problem for you, you can use a resistor of appropriate value. Power can be taken from the capacitor.
Another option is to use a smaller Tx as the standby PSU

 

Mind you a PC uses push button switches which are temporary.
That circuit requires a toggle switch.
A PC power button will just on the relay when pressed and switch off the relay when the button is released.

So I believe you are better off with a power toggle switch