High current 1.5A x150V power supply design for 100 IN9s

[Phill Scan]

Hi all,

I hope you didn't click on this post hoping to find such a circuit.

It's actually what I am looking for !

I want to drive 100 IN-9 Nixie's in a circuit.

So based on say 12mA per tube Max at say 150V I am going to need a LOT of current.

1.5A has a sufficient safety margin (I think).

I don't think lot's of little charge pump style circuits are going to be the most efficient way to run this !

I was thinking of running it off a 24VAC Plugpack ?. Don't want to run it using a mains cord.

Any clues on where to start such a circuit would be appreciated.

It should not  be bulky so don't want any large transformers ? 

Probably could get away with one large flat torroid though ?

If there are any power supply guru's here, we could come to some arrangement with remuneration if you like ?

[Phill Scan]

Humm.... I think something like this maybe ?

Seems to want car batteries to run it though !

So perhaps not plug pack compatible :-(

http://www.instructables.com/id/The-ZVS-driver/

[JohnK]

So, off-the-shelf mains inverter PLUS simple power supply circuit from the mains volts, OR add a transformer and rectifier/filter. ??

If safety is an issue, a zillion small powersupplies ?

John K

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[Phill Scan]

Hey Johnk,

I am trying to keep it small ... 

I think you are right an Inverter looks like the way to go.

Safety is very important. 

But even with lot's of little supply circuits it's still dangerous.

For instance, Three neurons HVPS kit still gives out 29mA at 170V ..... which is probably enough to kill you, depending on how you hooked yourself up to it.

Looking at inverter circuits now.

I don't know if anyone has seen this site ... http://www.rmcybernetics.com/

They are making some interesting HV stuff.

[Phill Scan]

Answering my own question here.

I guess I don't have to reinvent the wheel after all.

9A output up to 500V... madness.

http://www.rmcybernetics.com/shop/cyber-circuits/pulse-modulator-ocxi

[gregebert]

There's nothing inherently unsafe about non-isolated supplies; like any high-voltage project, you have to be careful about keeping everything properly insulated and follow minimum-spacing rules carefully.

The most-dangerous item in a high-current supply is the electrolytic cap. You *must* handle all of these concerns

• Extra margin for voltage-rating. I use 450V (500V when possible) caps for ~200V supplies. Higher voltage ratings also reduce leakage current. Caps designed for solar-energy inverters are perfect because they come in high-voltage + high temp + high ripple-current.
• Be very conservative with rms ripple-current, because it directly affects self-heating. Obviously you dont want any warm components near your capacitors. Remember: Lifetime is dramatically impacted by temperature.
• You must have a discharge resistor; I even put a flashing neon bulb across my large caps to indicate they have dangerous voltage. Larger resistance values take longer to discharge, but they reduce wasted energy (heat)
• Series fusing. In case the cap fails, you want to blow a fuse, not the cap. The fuse must be a small as possible, and dont forget the RMS charging current is not sinusiodal. BTW, this fuse is for the cap; it's in-addition to the fuse at the AC input.
• Charging-current needs to be limited during power-up. For the 1.5 amp supply, a 1500uF cap will have 10 volts of ripple at 50Hz when using a full-wave rectifier. I'd suggest a series charging resistor of about 200 ohms to charge at power-on, then 'shorting' the resistor with a relay after charging is done.
• Surge protection at the AC input. I always have a fuse on both AC lines, then a varistor and 0.01uF capacitor (for filtering hash noise if it's present). If your current is 'low' (which isn't the case in this design), adding series resistance to create an RC filter is a big help, and furthermore the resistors will act as secondary fuses if you pick low-enough wattage.
• Reverse-polarity protection diode. If you dont use a bridge rectifier, be sure to put a protection diode across the cap. BTW, a bridge-rectifier gives you reverse-polarity protection down to 1.4V, whereas a single diode is 0.7V. Polarized electrolytics caps can be damaged with as little as 1 volt of reverse voltage, so you may want to add the diode even if a bridge rectifier is used.

[Jonathan F.]

The link you showed. The device does NOT make the voltage higher, you have to supply a high voltage, and it can be controlled (pwm). The low voltage is only to power the circuit...

To get 150V @ 1.5A you would need at least 10A @ 24V, but depending on converter efficiency, it will be 12-15A.

Personally, i would build a off line DCDC converter. Or i would just take a suitable flat transformer, would be the easiest solution, remember that a 24V 15A Supply needs alot of space to...

[Jonathan F.]

http://www.tube-tester.com/sites/nixie/nixie-clock-cd47/cd47.htm

Maybe this could be helpful

[Phill Scan]

All excellent points.

Having been on the fixing end of this stuff but never design I never really thought about the how's and why's of certain layouts.

They just worked or they didn't.

Electronic design engineer I am not.

Though I am very well aware of just how dangerous electrolytics are ... having been responsible for letting the smoke out of them on various occasions.

Choosing cap's seems to be a black art.

I think I need a pro. The link Jonathan F pointed too has opened my eyes.

Flyback is needed here I think.

[chuck richards]

Several years ago I needed about 1.5 amps at 175 volts to
power up my array of (16) B-7971 tubes.

Found on Ebay a very nice old Hewlett Packard model 395A adjustable
power supply. It puts out 0 to 1.5 amps over a range of 0 to 320
volts DC.

It is a 19 inch rack-mountable unit.

It was in service at Los Alamos, NM at one time then sold as surplus.

After receiving it, I opened it up and vacuumed out a layer of
western desert fine red dust, cleaned it all up and put it in service
here to light up my scrolling B-7971 array.

Even contacted Agilent Technologies and found a guy there who
copied off the complete manual for it and sent it to me.

That is what I did when I needed a real power supply! :)

Chuck Richards

>
>
>---- Original Message ----
>From: fatma...@gmail.com
>To: neoni...@googlegroups.com
>Subject: RE: [neonixie-l] Re: High current 1.5A x150V power supply
>design for 100 IN9s

>>> - Extra margin for voltage-rating. I use 450V (500V when

>possible)
>>> caps for ~200V supplies. Higher voltage ratings also reduce
>leakage
>>> current. Caps designed for solar-energy inverters are perfect
>because they
>>> come in high-voltage + high temp + high ripple-current.

>>> - Be very conservative with rms ripple-current, because it

>directly
>>> affects self-heating. Obviously you dont want any warm
>components near your
>>> capacitors. Remember: Lifetime is dramatically impacted by
>temperature.

>>> - You must have a discharge resistor; I even put a flashing

>neon bulb
>>> across my large caps to indicate they have dangerous voltage.
>Larger
>>> resistance values take longer to discharge, but they reduce
>wasted energy
>>> (heat)

>>> - Series fusing. In case the cap fails, you want to blow a

>fuse, not
>>> the cap. The fuse must be a small as possible, and dont forget
>the RMS
>>> charging current is not sinusiodal. BTW, this fuse is for the
>cap; it's
>>> in-addition to the fuse at the AC input.

>>> - Charging-current needs to be limited during power-up. For the

>1.5
>>> amp supply, a 1500uF cap will have 10 volts of ripple at 50Hz
>when using a
>>> full-wave rectifier. I'd suggest a series charging resistor of
>about 200
>>> ohms to charge at power-on, then 'shorting' the resistor with a
>relay after
>>> charging is done.

>>> - Surge protection at the AC input. I always have a fuse on

>both AC
>>> lines, then a varistor and 0.01uF capacitor (for filtering hash
>noise if
>>> it's present). If your current is 'low' (which isn't the case
>in this
>>> design), adding series resistance to create an RC filter is a
>big help, and
>>> furthermore the resistors will act as secondary fuses if you
>pick
>>> low-enough wattage.

>>> - Reverse-polarity protection diode. If you dont use a bridge

>>> rectifier, be sure to put a protection diode across the cap.
>BTW, a
>>> bridge-rectifier gives you reverse-polarity protection down to
>1.4V,
>>> whereas a single diode is 0.7V. Polarized electrolytics caps
>can be damaged
>>> with as little as 1 volt of reverse voltage, so you may want to
>add the
>>> diode even if a bridge rectifier is used.
>>>
>>>
>>

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[Phill Scan]

Yup... I see that now. After actually reading the PDF I see that an external PSU is needed.

Calculations. Yes ... good idea ! :-)

You are right of course, I would need a huge "plugpack" ... something along the lines of a laptop style one.

And it would not be putting out low voltage either which kind of defeats the purpose.

So .. back to square one for me ... supply into the device must be AC from the mains.

[Instrument Resources of America]

Yes!!! And that supply, like most other HP gear, will probably out last
the both of us. Ira.

[JohnK]

I thought you said it had to be car batteries?

 

BTW, unrelated, but something I am reading at present. A valve/tube-based analogue computer...... attached is power supply requirement. Makes my rack mount telemetry power supplies look puny. I'll keep an eye out for neon :-).

 

jk

----- Original Message -----

From: Phill Scan

To: neonixie-l

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[robin bussell]

On 10/02/2016 05:24, JohnK wrote:
> So, off-the-shelf mains inverter PLUS simple power supply circuit from
> the mains volts, OR add a transformer and rectifier/filter. ??
> If safety is an issue, a zillion small powersupplies ?
> John K

If you want to go the many small supplies route then I did a little PCB
for tayloredge 1363 PSUs (45mA @ 170v), as seen here:
http://dirtypcbs.com/view.php?share=14240&accesskey=03a603186ce693a85368e67043d333fd

I have plenty spare as I got a batch made and only used two, I can send
you six (capacity of 36 1363 PSUs in total ) and you'll be able to mount
more than enough 1363 to fulfill your needs (I make it 34 at 45mA each),
won't be the highest density I'll admit but maybe the thing you're
making will benefit from PSUs distributed throughout its structure?

Cheers,
Robin.

[Phill Scan]

Helpful indeed. Now I know how big the supply will look with a flyback circuit !... 

Very impressive supply. The designer obviously has excellent skills.

The transformer is a bit of a black box though. 

The whole thing has been made for just that particular type of trannie.

[Phill Scan]

No .. I was just saying that that circuit you pointed to on indestructibles was using car batteries.

[Phill Scan]

Humm... I am going to have to think about this ... I am not sure I will have the room for lots of little supplies.

[JohnK]

BTW, when I said lots of small supplies i should also have said don't parallel the outputs - just have one common.

 

jk

----- Original Message -----

From: Phill Scan

To: neonixie-l

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[Mark Moulding]

I may be under-thinking his, but how about an off-the-shelf cigarette-lighter inverter? These are available in any desired power, and a 200 watt one is pretty compact.  Just throw a bridge rectifier after it with a filter capacitor, and perhaps some sort of post-regulator if necessary, and you're done.

If you're feeling adventurous, you could hack into the circuit and just run directly off the DC bus that it already has internally...

~~
Mark Moulding

[Charles MacDonald]

I think it was on this list that someone once mentioned finding a used
ELECTROPHORESIS power supply for less than a general purpose one. these
tend to be in the right range but are surplus to chem or Bio labs rather
then engineering departments. May not have the current you want and
they tend to have a timer which MOST let you ignore and run continuously.

YMMV, And all that jazz.



--
Charles MacDonald Stittsville Ontario
cm...@zeusprune.ca Just Beyond the Fringe
No Microsoft Products were used in sending this e-mail.

[Quixotic Nixotic]

What all those neons mean on the front of an Eniac...

What you could do on an Eniac…

And how the rest are related…

John S

[David Forbes]

Amusingly, the ENIAC was not a stored-program machine, so it doesn't really
belong at the trunk, but was one of the roots under the ground. EDVAC was the
first American stored-program machine.

A better computer to put at the trunk would be the Manchester Baby, as it was
the first functioning machine that actually had RAM from which instructions were
fetched, as do all modern computers other than tiny PIC-like things. The EDVAC
was the closest American thing, but it first ran a year later and didn't have
RAM, but shift register storage.

But this tree chart is American, so you get what you pay for.

On 2/11/2016 3:18 PM, Quixotic Nixotic wrote:
> What all those neons mean on the front of an Eniac...
>
>

> What you could do on an Eniac…
>
>

> And how the rest are related…
>
>

> John S
>


--
David Forbes, Tucson, AZ

[Phill Scan]

Just looked around on ebay and are cheap.

Yes they are plenty of them and some are quite small.

I like the thinking .... :-)

Thanks !

[Phill Scan]

Wow .. first one I looked at was spot on.

They don't look easy to find cheaply though.

Still sniffing around.

All good stuff guys and very much appreciated

[Quixotic Nixotic]

The 20 accumulators that could store a ten digit signed number I suppose is ram. When my father worked on an Eniac in the 1960s he used punched cards for storage. I guess it was just an overblown calculator.

I attach a memo of computer usage from 1954,

John S

On 11 Feb 2016, at 22:38, David Forbes wrote:

Amusingly, the ENIAC was not a stored-program machine, so it doesn't really belong at the trunk, but was one of the roots under the ground. EDVAC was the first American stored-program machine.

[Quixotic Nixotic]

On 11 Feb 2016, at 22:38, David Forbes wrote:

Amusingly, the ENIAC was not a stored-program machine, so it doesn't really belong at the trunk, but was one of the roots under the ground. EDVAC was the first American stored-program machine.

A better computer to put at the trunk would be the Manchester Baby, as it was the first functioning machine that actually had RAM from which instructions were fetched, as do all modern computers other than tiny PIC-like things. The EDVAC was the closest American thing, but it first ran a year later and didn't have RAM, but shift register storage.

I have this lovely picture of Edvac, David. I cannot see this without thinking that the man at the back (who never gets the girls) has malicious intent and is going to seriously screw over that guy who is about to twiddle the only knob that matters. In short I get a sense of drama.

[Alex]

I was planning a large IN-9 display a while back, and was going to simply use a toroidal isolating transformer, 230vac in, 115vac out - easily 250 or 300VA in a small toroid. Rectify, don't smooth it, simple current limit, job done and with full isolation from the mains.