1. Home
  2. Electronics Design
  3. PP-1104B/G power supply modification, another route?? (magnetic amplifier)

PP-1104B/G power supply modification, another route?? (magnetic amplifier)

This is a continuation of my efforts to understand how to best convert my PP-1104B/G power supply to a wider range of voltages and currents.

Check out this page

formatting link

and check out page 6-9 of this manual

formatting link

(manual for a similar supply 1104P/G)

It seems that, internally, the PP-1104B/G is controlled by reference voltage supplied to choke L3 as input to magnetic amplifier T2.

My question is this. Seemingly, instead of just adding on a linear regulator to the output of this power supply (brute force approach), a better modification can be made by controlling voltage supplied to choke L3 (and consequently magnetic amplifier T2) to achieve whatever is the desired voltage and current.

Is that correct? That is, can I add some abstract control circuit that would decide what voltage to supply as input to T2, to control this power supply better?

I think that I can use the same linear regulator type of thing to generate that control voltage, actually, except that now I control a much smaller current going into T2, rather than the whole output current. That means that the whole circuit can likely fit inside PP-1104B/G and would be controlled by a couple of extra pots. Such as "percentage of dialed voltage" and "max current" pots.

Makes sense?

i
Reply to
Ignoramus21657
Loading thread data ...

On a sunny day (Fri, 1 Dec 2006 15:59:11 +0000 (UTC)) it happened Ignoramus21657 wrote in :

Yes that is correct and is the way it is normally done. But remember, these things are _SLOW_, it takes time for the cores to magnetise, I have seen seconds reaction time in big power suplies like this. I used to control these with a thyristor. So with S1 at max setting, and a thyristor from the plus of bridge CR3 to the connection R4 L3pin1. Then control the firing angle of that thyristor from your control circuit that uses a voltage reference.

1% volatge regulation should be doable, but het this was sixties for me....

That means that the whole circuit can likely fit inside

Oh yes, but current limit reaction time would be slow too!!! The big ones I worked with had a magnetic relay that would cut power, even if just to protect the diodes. (magnetic latching relay with primary one loop of the output current, so off is off).

Experiment :-)

Reply to
Jan Panteltje

Seconds? I thought that the tmie to react was about half of the AC cycle, but I am sure that you are right.

I thought that I would control that voltage with a simple linear regulator, would that not be easier than with a thyristor?

Thanks... I guess reaction speed depends on my application, which would be slow processes like motor driving, plating, or battery charging.

i
Reply to
Ignoramus21657

On a sunny day (Fri, 1 Dec 2006 19:07:04 +0000 (UTC)) it happened Ignoramus21657 wrote in :

this.

Well I have to go back to 196x or so, I remember we had big ones 440V 150A and these went whooooooooooom when going on (say who...oom and you have the time).

You can, I have seen that too, but that uses power.... the thyristor is a switch and does not use any, the control module I designed was size of a pack of cigarettes.

You could even consider doing a on / of for n cycles with a transistor or thyristor, where the ratio of cycles on versus of changes.

When charging batteries (something we used this for), batteries can have very low impedance, current limit needs to work. I have seen current transformers used in the primary, shunts in the output too.

What I remember :-)

Experiment :-) No guarantees.

Reply to
Jan Panteltje

this.

Yeah, but I need to figure out its firing angle...

Much more complicated, I am a electronics newbie, my only electronics project was conversion of a SCR fired welder to microprocessor control.

i

Reply to
Ignoramus21657

On a sunny day (Sat, 2 Dec 2006 00:50:10 +0000 (UTC)) it happened Ignoramus21657 wrote in :

So am I, have been since the nineteen fifties, since as kid started playing with the radio, wiring the house so I could hear it in my room, build xtal receiver etc..

The speed things are going I always will be newbee.

Reply to
Jan Panteltje

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.