high power supply

R!f@@

Joined Apr 2, 2009
9,682
So we did not screw up with Ns.

Now load it across the winding which is 56.4VAC.

Load it till it drops to around 49VAC.

If u can't measure current, use separate but identical loads and add them one by one. This way u can make an approximated value
 

Thread Starter

spankey666

Joined Nov 30, 2011
91
i guess so :) its very hard trying to get measurements, holding a smallish piece of aluminium in a tank of acid at these currents cause it to boil and splatter instantly, so submerging it enough to get exact measurements is rather tricky, but i think we are there. if i lower the ali in a bit further, the ammeter goes off the scale, but i cannot hold it accurately enough to get a voltage reading at 100amps. plus the ali anodises instanly , so builds up resistance very quickly.
so i reckon if i make the ps capable of handling 120Amps but limit the output to 70 ish we should be good.one other thing i should mention, the shunt for the ammeter needs to be on the negative rail to avoid sudden voltage spikes should the parts loose connection under load.
 

Thread Starter

spankey666

Joined Nov 30, 2011
91
all i have is a large plate bridge rectifier from a welding plant rated at 180amps.no filter caps
so i need to buy everything.
i was looking at the possibility of buying and using a 3 phase bridge (just using 2 phases )as the one i have takes up a large proportion of the case.but this isnt high on my priorities yet .
 

R!f@@

Joined Apr 2, 2009
9,682
What u buy is up to u.
So tell me, are u going to buy the filter caps.

I showed something in an earlier post. The Capacitor voltage should be no less than 63VDC. The μF value is something of a bargain.

Since u decided to keep the plating method a secret I dunno whether the plating will need smooth DC or a little ripple can be tolerated.

U decide how much ripple in the DC bus u can get away with.

I can give u a standard method. 1000μF per Amp is a rule of thumb.
I remember saying to buy 100,000μF. 10 caps of 10,000μF will be best for ur app.

Like I said the caps is up to u. But remember the more ripple u have in the DC bus will cause premature capacitor failure and other freakin problems as I never tried dumping 74Amps in to anything. :D

As for the Bridge.
You will actually need two diodes. Try to find stud mount diodes rated at no less than 100V PIV. Diode If should be around 200amps. Stud mount is easire to deal with since it will have Lug connections. So it will be pretty easy to handle and connect wires to it.

If u decide to buy this lemme know. Cause I am going to make PCB's for my PSU. So the controller is the same for u too. The difference will be the Pre-drive, Driver & the power transistor. And these are not located on the PCB, even in my case.

Jens will be making the PCB's for me. So if you want he can make a few more in the process.
 

Thread Starter

spankey666

Joined Nov 30, 2011
91
LOL....
the plating method is no secret, theres lots of info on how to anodise on line.
plating can be done with raw rectified dc with no smoothing, so just a transformer and rectifier ....thats it, its controlling the current and the voltage where the issues are :(
i've got all my own stuff for making the pcb and am quite happy to design my own but thank you for the offer.
as i said before, i have to buy every thing else from scratch.
just did a search on 200a diodes.......WOW !! how much ???!!
 

R!f@@

Joined Apr 2, 2009
9,682
Told you to teach me the art but you were like hush hush!

If u need to control the current than apply the uF/amp rule and get the caps.
I guess 200amps were a bit over kill. We'll include surge limiter and use 100amps diode.

So find them. I have given a link somewhere before. Anyways the diodes problem is ur's not mine.

So, is it time for the schematic ?.

I am going off line after this post. Be back after a few hrs.
 

R!f@@

Joined Apr 2, 2009
9,682
I did not say u cannot do that, u said something abt space restrictions.

If u wanna use the diode plate, who am I to argue ?

If diode problem is solved it's time to move on to the filter caps.
 
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