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

[Ignoramus21657]

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

http://yabe.algebra.com/~ichudov/misc/ebay/PP-1104C_G-DC-Power-Supply-1/

and check out page 6-9 of this manual

http://yabe.algebra.com/~ichudov/mi...Power-Supply-1/PP-1104C_G--Power-Supply-1.pdf

(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

 

[Jan Panteltje]

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.

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

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?

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

 

[Ignoramus21657]

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.

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

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....

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

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

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

i

 

[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.

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).

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

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.

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

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.

 

[Ignoramus21657]

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.

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

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.

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

i

 

[Jan Panteltje]

Much more complicated, I am a electronics newbie,

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.