Bench Supply 2kV at 100mA - Circuits? - UK Vintage Radio Repair and Restoration Discussion Forum

jamesinnewcastl · 1st Jun 2018, 8:01 am

Hi All

I've just been reading a post about applying high test voltages to valves which reminded me about a power supply I have in the bottom of my cupboard at home. I'll post a picture tonight but it looks just like a typical bench supply but with a delightfully nasty output capability.

I believe that such a supply is used for electrophoresis but could be wrong.

I also believe that it uses a variable saturation technique to control the output voltage while still providing a deadly current - there are two very big wound items inside.

So, does anyone else have a similar item (perhaps with a circuit to study) or is anyone familiar with the saturation techinique?

I'll post part number and pics tonight! Incidentally I've never loaded it at all and only ever powered it up once since I could not believe the rating. The output changes quite slowly I recall.

Cheers
James

Radio Wrangler · 1st Jun 2018, 8:28 am

Look up:

Saturable reactors
Transductors
and Magnetic amplifiers.

I've used saturable reactor techniques to independently regulate multiple outputs from a single SMPS.

David

Techman · 1st Jun 2018, 12:30 pm

Yes, I've got a 6KV one. There's usually a large limiting resistor in the output IIRC.

Superscope · 3rd Jun 2018, 11:44 am

Hi James,

I can't help you with this, but I certainly
would be interested in seeing some Photo's of this
Monster!

One way to test out the Kv section on an AVO I guess!

Ian

Superscope · 26th Sep 2018, 7:34 am

When this Thread started some Months back, I didn't have
anything similar in my range of Test Equipment.

However, I recently acquired an LKB Bromma 2197
which might be similar in operation to the OP Bench Supply.
I have no knowledge of variable saturation techniques, so I
can't really comment on that one.

I have attached a Schematic for anybody interested.

This Bench PSU was also designed for electrophoresis, and can output 2500 Volts at 250 mA.
It's a very neat and compact device, just with a very Scary output.

There isn't a lot of information on the Web about this particular PSU, but I
can confirm it is very nicely built.

Ian

jamesinnewcastl · 26th Sep 2018, 8:11 am

Hi Ian

I never got back on this one and probably won't for a while as my PSU is packed away somewhere in preperation for a house move (along with all my other hobby stuff - sigh)

Your device looks like a high frequency transformer step-up circuit using PWM for regulation and lots of low-ish voltage secondarys in series. My device is very much simpler. I remember that it has two enormous, heavy 'transformers' and a small PCB with a few components on.

I will have a look tonight to see if my one is still around somewhere accessible!

I've only turned mine on twice.....

Cheers
James

Radio Wrangler · 26th Sep 2018, 8:16 am

This one doesn't use magnetic amplifier techniques. There is a nice isolating mains transformer, all outputs rectified and smoothed. From this is powered a push-pull inverter driven by a common Silicon General SMPS control chip. The inverter has sectional windings for its secondary, each section with its own rectifier to force voltage sharing.

Then some opamps monitor and regulate the output voltage. There's an ADC in there so I assume (I haven't looked deeply) this makes the output programmable.

David

jamesinnewcastl · 26th Sep 2018, 5:29 pm

Hi

Found the item! Here are some pics...

James

Ed_Dinning · 26th Sep 2018, 9:12 pm

Hi James, it looks quite a modern beast, so should work well, but beware as it could easily kill.

Ed

Radio Wrangler · 26th Sep 2018, 9:25 pm

It seems to be rather lacking in warning labels for something which looks so recent. Not so much a a lightning bolt symbol.

David

jamesinnewcastl · 26th Sep 2018, 10:52 pm

Hi Ed

That's why I've only switched it on twice! It does output the voltage advertised but I've never loaded it. The response to the adjustment knob is quite slow but was probably due to that long string of capacitors and no load.

The company named on the item deny its existance.

It's the lack of any high frequency components that make me think that it is a saturable inductance device - which would have a frighteningly low output impedance!

David - It must be the case that the guys using electrophoresis back then were well aware of the issues!

One day I will chase out the circuit. When I get my retirement 'shed' it's going to be part of my toy box. Then I'll try a few of these experiments!

http://www.sparkbangbuzz.com/index.html

Cheers
James

Dekatron · 26th Sep 2018, 11:25 pm

The power supply was discontinued in 1993 according to the list on the manufacturers website: https://www.atto.co.jp/site/support/production_end , maybe they can send you a manual?

/Martin

karesz* · 27th Sep 2018, 9:36 am

Hi James,

Code:

The response to the adjustment knob is quite slow

Its OK, then HV-PSUs have slowly to act for hes adjustings...
Regards, Karl

27th Sep 2018, 1:44 pm

SHMBO has used such devices in her work, the worrying thing is that the output is put into a wet environment, open top, clear perspex. One of these was called affectionately "Old Sparky". I have seen one doing electrophoresis, it (the electophoretic bit) quite merrily fizzed and crackled away, at least it sounded dangerous. All connected by banana plugs, unshielded both ends!
Before anyone asks SHMBO is alive and well.

Ed_Dinning · 27th Sep 2018, 9:12 pm

Hi James, when you get a chance you can bring it over and we can try it on a BIG resistor load.

Ed

M0FYA Andy · 27th Sep 2018, 9:24 pm

Totally off-topic, but if you want to see something dangerous then watch this fascinating video -
https://www.youtube.com/watch?v=zAvurSjBVW8
Count how many ways that could kill you...………
Andy

1st Jun 2018, 8:01 am	#1
jamesinnewcastl Heptode Join Date: Jul 2009 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 722	Bench Supply 2kV at 100mA - Circuits? Hi All I've just been reading a post about applying high test voltages to valves which reminded me about a power supply I have in the bottom of my cupboard at home. I'll post a picture tonight but it looks just like a typical bench supply but with a delightfully nasty output capability. I believe that such a supply is used for electrophoresis but could be wrong. I also believe that it uses a variable saturation technique to control the output voltage while still providing a deadly current - there are two very big wound items inside. So, does anyone else have a similar item (perhaps with a circuit to study) or is anyone familiar with the saturation techinique? I'll post part number and pics tonight! Incidentally I've never loaded it at all and only ever powered it up once since I could not believe the rating. The output changes quite slowly I recall. Cheers James

1st Jun 2018, 8:28 am	#2
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,870	Re: Bench Supply 2kV at 100mA - Circuits? Look up: Saturable reactors Transductors and Magnetic amplifiers. I've used saturable reactor techniques to independently regulate multiple outputs from a single SMPS. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

1st Jun 2018, 12:30 pm	#3
Techman Dekatron Join Date: Nov 2009 Location: Lincolnshire, UK. Posts: 5,000	Re: Bench Supply 2kV at 100mA - Circuits? Yes, I've got a 6KV one. There's usually a large limiting resistor in the output IIRC.

3rd Jun 2018, 11:44 am	#4
Superscope Octode Join Date: May 2017 Location: St Austell, Cornwall, UK. Posts: 1,018	Re: Bench Supply 2kV at 100mA - Circuits? Hi James, I can't help you with this, but I certainly would be interested in seeing some Photo's of this Monster! One way to test out the Kv section on an AVO I guess! Ian

26th Sep 2018, 8:11 am	#6
jamesinnewcastl Heptode Join Date: Jul 2009 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 722	Re: Bench Supply 2kV at 100mA - Circuits? Hi Ian I never got back on this one and probably won't for a while as my PSU is packed away somewhere in preperation for a house move (along with all my other hobby stuff - sigh) Your device looks like a high frequency transformer step-up circuit using PWM for regulation and lots of low-ish voltage secondarys in series. My device is very much simpler. I remember that it has two enormous, heavy 'transformers' and a small PCB with a few components on. I will have a look tonight to see if my one is still around somewhere accessible! I've only turned mine on twice..... Cheers James

26th Sep 2018, 8:16 am	#7
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,870	Re: Bench Supply 2kV at 100mA - Circuits? This one doesn't use magnetic amplifier techniques. There is a nice isolating mains transformer, all outputs rectified and smoothed. From this is powered a push-pull inverter driven by a common Silicon General SMPS control chip. The inverter has sectional windings for its secondary, each section with its own rectifier to force voltage sharing. Then some opamps monitor and regulate the output voltage. There's an ADC in there so I assume (I haven't looked deeply) this makes the output programmable. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

26th Sep 2018, 5:29 pm	#8
jamesinnewcastl Heptode Join Date: Jul 2009 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 722	Re: Bench Supply 2kV at 100mA - Circuits? Hi Found the item! Here are some pics... James Attached Thumbnails

26th Sep 2018, 9:12 pm	#9
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,194	Re: Bench Supply 2kV at 100mA - Circuits? Hi James, it looks quite a modern beast, so should work well, but beware as it could easily kill. Ed

26th Sep 2018, 9:25 pm	#10
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,870	Re: Bench Supply 2kV at 100mA - Circuits? It seems to be rather lacking in warning labels for something which looks so recent. Not so much a a lightning bolt symbol. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

26th Sep 2018, 10:52 pm	#11
jamesinnewcastl Heptode Join Date: Jul 2009 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 722	Re: Bench Supply 2kV at 100mA - Circuits? Hi Ed That's why I've only switched it on twice! It does output the voltage advertised but I've never loaded it. The response to the adjustment knob is quite slow but was probably due to that long string of capacitors and no load. The company named on the item deny its existance. It's the lack of any high frequency components that make me think that it is a saturable inductance device - which would have a frighteningly low output impedance! David - It must be the case that the guys using electrophoresis back then were well aware of the issues! One day I will chase out the circuit. When I get my retirement 'shed' it's going to be part of my toy box. Then I'll try a few of these experiments! http://www.sparkbangbuzz.com/index.html Cheers James

26th Sep 2018, 11:25 pm	#12
Dekatron Octode Join Date: May 2009 Location: Linkoping, Sweden Posts: 1,465	Re: Bench Supply 2kV at 100mA - Circuits? The power supply was discontinued in 1993 according to the list on the manufacturers website: https://www.atto.co.jp/site/support/production_end , maybe they can send you a manual? /Martin __________________ Martin, Sweden

27th Sep 2018, 9:36 am	#13
karesz* Heptode Join Date: Jun 2010 Location: Zurich, Switzerland Posts: 538	Re: Bench Supply 2kV at 100mA - Circuits? Hi James, Code: The response to the adjustment knob is quite slow Its OK, then HV-PSUs have slowly to act for hes adjustings... Regards, Karl

27th Sep 2018, 1:44 pm	#14
Guest Guest Posts: n/a	Re: Bench Supply 2kV at 100mA - Circuits? SHMBO has used such devices in her work, the worrying thing is that the output is put into a wet environment, open top, clear perspex. One of these was called affectionately "Old Sparky". I have seen one doing electrophoresis, it (the electophoretic bit) quite merrily fizzed and crackled away, at least it sounded dangerous. All connected by banana plugs, unshielded both ends! Before anyone asks SHMBO is alive and well.

27th Sep 2018, 9:12 pm	#15
Ed_Dinning Dekatron Join Date: Jan 2004 Location: Newcastle upon Tyne, Tyne & Wear, UK. Posts: 8,194	Re: Bench Supply 2kV at 100mA - Circuits? Hi James, when you get a chance you can bring it over and we can try it on a BIG resistor load. Ed

27th Sep 2018, 9:24 pm	#16
M0FYA Andy Nonode Join Date: May 2007 Location: Preston, Lancashire, UK. Posts: 2,511	Re: Bench Supply 2kV at 100mA - Circuits? Totally off-topic, but if you want to see something dangerous then watch this fascinating video - https://www.youtube.com/watch?v=zAvurSjBVW8 Count how many ways that could kill you...……… Andy