Bench Power Supply

[Ayne]

I want to make a power supply for my work bech.
I make this circuit which is below.
**broken link removed**
I request to Experts, Plz check it and find the errors.
It will work OR not??

I use OP_AMP and relays for switching to other windings.
My idea is,
when the output voltages increase more than 12 volts op-amp will ON the relay and U1 and U2 will switch to other windings.
C & C are welcomes.
Thanks.

 

[Optikon]

I want to make a power supply for my work bech.
I make this circuit which is below.

I request to Experts, Plz check it and find the errors.
It will work OR not??

I use OP_AMP and relays for switching to other windings.
My idea is,
when the output voltages increase more than 12 volts op-amp will ON the relay and U1 and U2 will switch to other windings.
C & C are welcomes.
Thanks.

Why do you connect your common output terminals (floating grounds) through resistors back at the winding output?

I didnt trace out the schematic for errors but why do feel the need to do any switching with relays?

 

[Ayne]

Best way for connecting

Why do you connect your common output terminals (floating grounds) through resistors back at the winding output?

I thinks it is the good way for connecting both common output terminals together for making ground but i don't know why.

but why do feel the need to do any switching with relays?

Suppose i am using LM317 for 7Volts output at 1Ampere. If it's input voltages equal to 25 volts then 
Voltage drop across LM317 = Vin - Vout = 25 - 7 = 18 Volts.
Current through LM317 = 1A approx
Wattage of LM317 on this position = Voltage drop across LM317 * Current through LM317
Wattage of LM317 on this position = 18 Volts * 1A = 18 watt

It mean it will dissipate more power in heat.
It is better choice to switch to lower voltages when it is used for low voltages.
Sorry for my poor English. Hope this may help.

Plz do electrical check and trace out the schematic for errors.

I also wan to ask that which is the better way for connecting both common points. Pictures are below.

 

[Nigel Goodwin]

I also wan to ask that which is the better way for connecting both common points. Pictures are below.

There is no need for the resistors, and they would be detrimental to it's operation.

 

[Hero999]

Why are you using two seperate winding?

Why not one with two 11V taps either side of 0V like I suggested in the other thread?

 

[Ayne]

Thanks

Why are you using two seperate winding?

Why not one with two 11V taps either side of 0V like I suggested in the other thread?

I had rewind my transformer already before reading ur that post. And now i cannot reopen my transformer for rewinding.

Below is the picture. I want to ask that it will work.. If it will work then where to add bridge and capcacitors in it???

 

[Optikon]

I had rewind my transformer already before reading ur that post. And now i cannot reopen my transformer for rewinding.

Below is the picture. I want to ask that it will work.. If it will work then where to add bridge and capcacitors in it???

There is no problem with stacking windings the way you do (from the transformer side of things) but it depends on what kind of performance you are after. It is not the way I would do it.

Also, you may want to consider reviewing your transformer and design _before_ you wind it and put everything together.. otherwise, whats the point in asking if you cant change it?

 

[Ayne]

Requested For PCB.

I request to Experts to Plz do electrical check and trace out the schematic for errors.
If there is no error in then plz say "OK and ready to Make"

Any one will make a PCB of this circuit??
If some one have time and good experience in making PCB then plz make PCB of this circuit for us.

 

[JRoque]

Hello Ayne. I would have used a switching regulator that can be far more efficient and not have so much concerns about input requirements. But it looks like you're set to build it as designed. Do you have the original circuit in a format that can be imported to a capturing program? It's far easier to run check rules and eventually build a PCB.

JR

 

[Hero999]

Any one will make a PCB of this circuit??
If some one have time and good experience in making PCB then plz make PCB of this circuit for us.

How much do you want to pay?

No, this is your project not ours. We're all too pleased to help but we refuse to do all the work for you (not without payment anyway).

 

[Ayne]

Hello Ayne. I would have used a switching regulator that can be far more efficient and not have so much concerns about input requirements. But it looks like you're set to build it as designed. Do you have the original circuit in a format that can be imported to a capturing program? It's far easier to run check rules and eventually build a PCB.

JR

Yes, I have orignal file in ExpressSCH format, Which is attached below. Will u make a PCB of this circuit for us.
It is not only for me it is for us cuz every one needs a power supply to power their circuits.
If some one have already a schamatic diagram of a good power supply with it's PCB then plz share with us.

 

[JRoque]

Hello again Ayne. I was thinking that it would be easier to run a design check rule on your schematic, not necessarily designing the PCB. That is generally quite a bit of work and will require many emails back and forth, etc. For example, I have no idea what the dimensions are of your relays, etc. After having those components measured, there's a good chance that a custom footprint would have to be drawn so they can be added to the PCB. At the end of the day, we'll end up with a design captured in a proprietary format that cannot be exported to other software packages - as far as I know - and the PCB can only be manufactured by the makers of ExpressPCB.

Your design looks like it should work. You might want to look into hysteresis for the 12V switchover or else setting the power supply to exactly 12V might trigger the relay in and out constantly. Sorry I'm not being of much help here.

Regards,
JR

 

[Ayne]

Thanks JRoque