power supply switching...

[Bill Sloman]

On Friday, September 4, 2020 at 2:44:54 AM UTC+10, jla...@highlandsniptechnology.com wrote:

I\'m thinking about a big new box, with three universal-input power
supplies in the back. The customer wants a power switch on the front.

I guess I can just run the AC through the switch. But that\'s big ugly,
maybe noisy wiring, and such switches tend to fail from inrush surge.

http://www.farnell.com/datasheets/2571023.pdf

It\'s their smallest and cheapest contactor - about $A30 so not all that cheap, but capable of switching at lot of current at mains voltage.

I had to put one into Cambridge Instruments cheapest electron microscope sometime around 1985.

<snip>

--
Bill Sloman, Sydney

 

[John Larkin]

On Thu, 3 Sep 2020 18:19:24 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-09-03 13:37, jlarkin@highlandsniptechnology.com wrote:
On Thu, 3 Sep 2020 10:24:54 -0700, John Robertson <spam@flippers.com
wrote:

On 2020/09/03 9:44 a.m., jlarkin@highlandsniptechnology.com wrote:


I\'m thinking about a big new box, with three universal-input power
supplies in the back. The customer wants a power switch on the front.

I guess I can just run the AC through the switch. But that\'s big ugly,
maybe noisy wiring, and such switches tend to fail from inrush surge.

Surge might be fixed with an NTC current limiter.

I could switch the input AC with a big relay in the back. But where
would I get the power to do that? I\'d need a power relay whose coil
operates from 100 to 240 volts.

Or switch the DC supply outputs with some mosfets.

Digikey has some small universal-input DC supplies, 12 or 24 VDC out,
for around $10. One of those could power the relay or the mosfet
circuit.

There would probably be a real power switch on the AC inlet/filter
brick; this would be a \"soft\" power switch.

Do modern PFC-corrected power supplies have big input current surges?
Gotta find out.

Any suggestions?




Don\'t over-design this! The customer wants a power switch? Give them one
that handles sufficient current to do the job, then +50 to +100% over.

The inrush could get close to 200 amps.



Fluke 9010As had a solution for the power switch (noise, electrical
safety, etc.) up front - they used a long push rod that worked the
push-on/push-off switch buried in the power supply box at the back of
the test gear.

Won\'t something like that help you with UL approval as well?

KISS

John ;-#)#

These people probably don\'t care about UL, but we may as well try to
stay within the UL/CE rules. A \"soft\" power switch would help some
there. A pushrod might be helpful, but we still need a switch. Maybe
DC switching after the power supplies, with giant mosfets, is the way
to go... if it doesn\'t get out of hand.




The canonical approach is a switch feeding a wirewound resistor that is
shunted by a relay.

Cheers

Phil Hobbs

We did that once, and the wirewould resistor died of fatigue. The
replacement was porcelain-on-steel, which held up fine.

But that was a much bigger load.

An NTC inrush limiter could be shunted by a relay when the DC comes
up. That sort of self-times.

 

[Phil Hobbs]

On 2020-09-03 20:34, John Larkin wrote:

On Thu, 3 Sep 2020 18:19:24 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-09-03 13:37, jlarkin@highlandsniptechnology.com wrote:
On Thu, 3 Sep 2020 10:24:54 -0700, John Robertson <spam@flippers.com
wrote:

On 2020/09/03 9:44 a.m., jlarkin@highlandsniptechnology.com wrote:


I\'m thinking about a big new box, with three universal-input power
supplies in the back. The customer wants a power switch on the front.

I guess I can just run the AC through the switch. But that\'s big ugly,
maybe noisy wiring, and such switches tend to fail from inrush surge.

Surge might be fixed with an NTC current limiter.

I could switch the input AC with a big relay in the back. But where
would I get the power to do that? I\'d need a power relay whose coil
operates from 100 to 240 volts.

Or switch the DC supply outputs with some mosfets.

Digikey has some small universal-input DC supplies, 12 or 24 VDC out,
for around $10. One of those could power the relay or the mosfet
circuit.

There would probably be a real power switch on the AC inlet/filter
brick; this would be a \"soft\" power switch.

Do modern PFC-corrected power supplies have big input current surges?
Gotta find out.

Any suggestions?




Don\'t over-design this! The customer wants a power switch? Give them one
that handles sufficient current to do the job, then +50 to +100% over.

The inrush could get close to 200 amps.



Fluke 9010As had a solution for the power switch (noise, electrical
safety, etc.) up front - they used a long push rod that worked the
push-on/push-off switch buried in the power supply box at the back of
the test gear.

Won\'t something like that help you with UL approval as well?

KISS

John ;-#)#

These people probably don\'t care about UL, but we may as well try to
stay within the UL/CE rules. A \"soft\" power switch would help some
there. A pushrod might be helpful, but we still need a switch. Maybe
DC switching after the power supplies, with giant mosfets, is the way
to go... if it doesn\'t get out of hand.




The canonical approach is a switch feeding a wirewound resistor that is
shunted by a relay.

Cheers

Phil Hobbs

We did that once, and the wirewould resistor died of fatigue. The
replacement was porcelain-on-steel, which held up fine.

But that was a much bigger load.

An NTC inrush limiter could be shunted by a relay when the DC comes
up. That sort of self-times.

The problem with NTCs is that there\'s no guarantee that multiple power
interruptions can\'t occur within their thermal TC. The relay + power
resistor approach is a lot easier to specify AFAICT. (Full disclosure:
I\'ve never designed an AC-powered box that didn\'t have a separate power
supply--they\'ve been so cheap and so good for so long that it never came
up.)

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[John S]

On 9/3/2020 11:44 AM, jlarkin@highlandsniptechnology.com wrote:

I\'m thinking about a big new box, with three universal-input power
supplies in the back. The customer wants a power switch on the front.

I guess I can just run the AC through the switch. But that\'s big ugly,
maybe noisy wiring, and such switches tend to fail from inrush surge.

Surge might be fixed with an NTC current limiter.

I could switch the input AC with a big relay in the back. But where
would I get the power to do that? I\'d need a power relay whose coil
operates from 100 to 240 volts.

Or switch the DC supply outputs with some mosfets.

Digikey has some small universal-input DC supplies, 12 or 24 VDC out,
for around $10. One of those could power the relay or the mosfet
circuit.

There would probably be a real power switch on the AC inlet/filter
brick; this would be a \"soft\" power switch.

Do modern PFC-corrected power supplies have big input current surges?
Gotta find out.

Any suggestions?

I don\'t know if this will work for your particular situation but very
interesting:

EEVblog at 14 minutes...

<https://www.youtube.com/watch?v=YYydU4l6sLo>

 

[John S]

On 9/4/2020 8:30 AM, John S wrote:

On 9/3/2020 11:44 AM, jlarkin@highlandsniptechnology.com wrote:


I\'m thinking about a big new box, with three universal-input power
supplies in the back. The customer wants a power switch on the front.

I guess I can just run the AC through the switch. But that\'s big ugly,
maybe noisy wiring, and such switches tend to fail from inrush surge.

Surge might be fixed with an NTC current limiter.

I could switch the input AC with a big relay in the back.  But where
would I get the power to do that? I\'d need a power relay whose coil
operates from 100 to 240 volts.

Or switch the DC supply outputs with some mosfets.

Digikey has some small universal-input DC supplies, 12 or 24 VDC out,
for around $10. One of those could power the relay or the mosfet
circuit.

There would probably be a real power switch on the AC inlet/filter
brick; this would be a \"soft\" power switch.

Do modern PFC-corrected power supplies have big input current surges?
Gotta find out.

Any suggestions?

I don\'t know if this will work for your particular situation but very
interesting:

EEVblog at 14 minutes...

https://www.youtube.com/watch?v=YYydU4l6sLo

Also at 24 minutes.

 

[Tabby]

On Friday, 4 September 2020 03:55:25 UTC+1, Phil Hobbs wrote:

On 2020-09-03 20:34, John Larkin wrote:
On Thu, 3 Sep 2020 18:19:24 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:
On 2020-09-03 13:37, jlarkin@highlandsniptechnology.com wrote:
On Thu, 3 Sep 2020 10:24:54 -0700, John Robertson <spam@flippers.com
wrote:
On 2020/09/03 9:44 a.m., jlarkin@highlandsniptechnology.com wrote:


I\'m thinking about a big new box, with three universal-input power
supplies in the back. The customer wants a power switch on the front.

I guess I can just run the AC through the switch. But that\'s big ugly,
maybe noisy wiring, and such switches tend to fail from inrush surge.

Surge might be fixed with an NTC current limiter.

I could switch the input AC with a big relay in the back. But where
would I get the power to do that? I\'d need a power relay whose coil
operates from 100 to 240 volts.

Or switch the DC supply outputs with some mosfets.

Digikey has some small universal-input DC supplies, 12 or 24 VDC out,
for around $10. One of those could power the relay or the mosfet
circuit.

There would probably be a real power switch on the AC inlet/filter
brick; this would be a \"soft\" power switch.

Do modern PFC-corrected power supplies have big input current surges?
Gotta find out.

Any suggestions?




Don\'t over-design this! The customer wants a power switch? Give them one
that handles sufficient current to do the job, then +50 to +100% over.

The inrush could get close to 200 amps.



Fluke 9010As had a solution for the power switch (noise, electrical
safety, etc.) up front - they used a long push rod that worked the
push-on/push-off switch buried in the power supply box at the back of
the test gear.

Won\'t something like that help you with UL approval as well?

KISS

John ;-#)#

These people probably don\'t care about UL, but we may as well try to
stay within the UL/CE rules. A \"soft\" power switch would help some
there. A pushrod might be helpful, but we still need a switch. Maybe
DC switching after the power supplies, with giant mosfets, is the way
to go... if it doesn\'t get out of hand.




The canonical approach is a switch feeding a wirewound resistor that is
shunted by a relay.

Cheers

Phil Hobbs

We did that once, and the wirewould resistor died of fatigue. The
replacement was porcelain-on-steel, which held up fine.

But that was a much bigger load.

An NTC inrush limiter could be shunted by a relay when the DC comes
up. That sort of self-times.




The problem with NTCs is that there\'s no guarantee that multiple power
interruptions can\'t occur within their thermal TC.

There\'s a guarantee that they can occur. It\'s not a problem.

The relay + power
resistor approach is a lot easier to specify AFAICT. (Full disclosure:
I\'ve never designed an AC-powered box that didn\'t have a separate power
supply--they\'ve been so cheap and so good for so long that it never came
up.)

Either works. Thermistors are just a partial solution to the issues fixed resistors create.


NT

 

[Chris Jones]

On 04/09/2020 05:52, John Larkin wrote:

On Thu, 03 Sep 2020 22:46:41 +0300, upsidedown@downunder.com wrote:

On Thu, 03 Sep 2020 10:37:58 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Thu, 3 Sep 2020 10:24:54 -0700, John Robertson <spam@flippers.com
wrote:

On 2020/09/03 9:44 a.m., jlarkin@highlandsniptechnology.com wrote:


I\'m thinking about a big new box, with three universal-input power
supplies in the back. The customer wants a power switch on the front.

I guess I can just run the AC through the switch. But that\'s big ugly,
maybe noisy wiring, and such switches tend to fail from inrush surge.

Surge might be fixed with an NTC current limiter.

I could switch the input AC with a big relay in the back. But where
would I get the power to do that? I\'d need a power relay whose coil
operates from 100 to 240 volts.

Or switch the DC supply outputs with some mosfets.

Digikey has some small universal-input DC supplies, 12 or 24 VDC out,
for around $10. One of those could power the relay or the mosfet
circuit.

There would probably be a real power switch on the AC inlet/filter
brick; this would be a \"soft\" power switch.

Do modern PFC-corrected power supplies have big input current surges?
Gotta find out.

Any suggestions?




Don\'t over-design this! The customer wants a power switch? Give them one
that handles sufficient current to do the job, then +50 to +100% over.

The inrush could get close to 200 amps.

You have to consider also the house wiring and house fuses.

If you use separate relays for each PSU, you could delay the turn on
for some of the PSUs, limiting the peak current to a manageable level.

n the US, if you have split phase (2 x 120 V) you could reduce the
current, but this requires a two pole relay.

If the issue is only relay contact rating (and not house fuses), just
get a three phase relay, so each contact has to handle only 60 A peak.
In the US, if 120/208 V three phase happens to be available, you could
run each PSU from own phase.

Of course, in the rest of the world a 1x230 V or 230/400 V three phase
could also be used with the same relay and only select between one and
three phases.

This won\'t be residential, but it could be used anywhere in the world.

Single phase.

I don\'t think that 600 watts of switching power supply will trip an AC
breaker on startup. I\'m confident it would eventually destroy a small
switch or relay.

You can get relays with tungsten pre-make contacts:
https://www.te.com/global-en/product-CAT-SCH691-R819A.html

Almost big enough for your load.

It is interesting to test a few relays to destruction by inrush current.
Under some conditions it does not take very long at all, with slightly
different conditions they keep going with no problems.

Regardless of how robust a switch or relay you can find, a better
solution might be to reduce the inrush current.

Especially if you manage to sell multiple instances of your product to
the same customer and they want to put them all on the same circuit, and
if they will sometimes switch on the power remotely to the whole
rack/installation, the total inrush current for the external contactor
can become unreasonable quite easily.

At least having a relay inside your product could stagger the inrush
current pulses, but reducing the magnitude of the inrush current might
be worthwhile too. It might also improve reliability - sometimes the
mechanism of failure during a mains surge is not excessive voltage, but
rather excessive current in the rectifier at the input of a SMPS, due to
the surge attempting to produce a very large dv/dt on the reservoir
capacitor.

 

[server]

On Sat, 5 Sep 2020 22:10:14 +1000, Chris Jones
<lugnut808@spam.yahoo.com> wrote:

On 04/09/2020 05:52, John Larkin wrote:
On Thu, 03 Sep 2020 22:46:41 +0300, upsidedown@downunder.com wrote:

On Thu, 03 Sep 2020 10:37:58 -0700, jlarkin@highlandsniptechnology.com
wrote:

On Thu, 3 Sep 2020 10:24:54 -0700, John Robertson <spam@flippers.com
wrote:

On 2020/09/03 9:44 a.m., jlarkin@highlandsniptechnology.com wrote:


I\'m thinking about a big new box, with three universal-input power
supplies in the back. The customer wants a power switch on the front.

I guess I can just run the AC through the switch. But that\'s big ugly,
maybe noisy wiring, and such switches tend to fail from inrush surge.

Surge might be fixed with an NTC current limiter.

I could switch the input AC with a big relay in the back. But where
would I get the power to do that? I\'d need a power relay whose coil
operates from 100 to 240 volts.

Or switch the DC supply outputs with some mosfets.

Digikey has some small universal-input DC supplies, 12 or 24 VDC out,
for around $10. One of those could power the relay or the mosfet
circuit.

There would probably be a real power switch on the AC inlet/filter
brick; this would be a \"soft\" power switch.

Do modern PFC-corrected power supplies have big input current surges?
Gotta find out.

Any suggestions?




Don\'t over-design this! The customer wants a power switch? Give them one
that handles sufficient current to do the job, then +50 to +100% over.

The inrush could get close to 200 amps.

You have to consider also the house wiring and house fuses.

If you use separate relays for each PSU, you could delay the turn on
for some of the PSUs, limiting the peak current to a manageable level.

n the US, if you have split phase (2 x 120 V) you could reduce the
current, but this requires a two pole relay.

If the issue is only relay contact rating (and not house fuses), just
get a three phase relay, so each contact has to handle only 60 A peak.
In the US, if 120/208 V three phase happens to be available, you could
run each PSU from own phase.

Of course, in the rest of the world a 1x230 V or 230/400 V three phase
could also be used with the same relay and only select between one and
three phases.

This won\'t be residential, but it could be used anywhere in the world.

Single phase.

I don\'t think that 600 watts of switching power supply will trip an AC
breaker on startup. I\'m confident it would eventually destroy a small
switch or relay.

You can get relays with tungsten pre-make contacts:
https://www.te.com/global-en/product-CAT-SCH691-R819A.html

Almost big enough for your load.

It is interesting to test a few relays to destruction by inrush current.
Under some conditions it does not take very long at all, with slightly
different conditions they keep going with no problems.

Regardless of how robust a switch or relay you can find, a better
solution might be to reduce the inrush current.

Looks like I\'ll have a giant AC inlet module on the back (IEC
connector, fuses, EMI filter, and switch) that turns on the three
power supplies. At DC levels, I\'ll have a mosfet-based switch board
between the supplies and the loads, with a tiny switch on the front
panel for that. That\'s a non-trivial design.

I need a Spice model for a MAX809. If I can\'t find one, I\'ll have to
hack an equivalent.

Especially if you manage to sell multiple instances of your product to
the same customer and they want to put them all on the same circuit, and
if they will sometimes switch on the power remotely to the whole
rack/installation, the total inrush current for the external contactor
can become unreasonable quite easily.

My customer doesn\'t like accessing things from the back of their
jammed racks, but they don\'t mind a soft switch on the front. But one
specific requirement is that it must not be switchable by a
technician\'s butt. They did not specify the size or gender of that
butt. Another research project, I guess.

And they want an air filter that is easily replaced from the front.

Never consult a customer before you design something.

At least having a relay inside your product could stagger the inrush
current pulses, but reducing the magnitude of the inrush current might
be worthwhile too. It might also improve reliability - sometimes the
mechanism of failure during a mains surge is not excessive voltage, but
rather excessive current in the rectifier at the input of a SMPS, due to
the surge attempting to produce a very large dv/dt on the reservoir
capacitor.

AC relay wiring would be a nuisance. The soft-switch thing can have
some big fastons for the DC connections, and a little ribbon cable to
the switch and a few LEDs on the front panel.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[server]

On Thu, 03 Sep 2020 17:55:24 GMT, Jan Panteltje
<pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Thu, 03 Sep 2020 09:51:07 -0700) it happened
jlarkin@highlandsniptechnology.com wrote in
lf72lf106d4t0jnkm5jp4liiuh8pl9pk3k@4ax.com>:

The MeanWell LRS-200 series specs a 60 amp typ inrush current. Times
three power supplies.

The PFC front-end is a boost converter. The AC line initially sees a
bridge, a smallish inductor, and a big cap.

Would a big triac work as power switch?
Drive it with some DC from a small supply that is powered by the power switch
Is that legal?
Over here you may need a real switch in the power line.
So maybe 2 switches, one big one to cut the mains,
and a push button thing or touch screen or whatever for on off.
No noise no sparks.
?

I designed a mosfet-based DC switch, but it\'s complex.

A big triac is a possibility. I could drive that with just a switch
and maybe a fusable resistor from anode to gate. That would put AC
line voltage on the little switch up front.

Maybe tiny power supply, DC switch, opto SSR, triac.

There would still be a giant, in practice inaccessable, switch on the
power inlet on the back.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[Jan Panteltje]

On a sunny day (Sat, 05 Sep 2020 10:52:02 -0700) it happened
jlarkin@highlandsniptechnology.com wrote in
<fgj7lfldvo0povaq838a5qtr9i1srd8amo@4ax.com>:

...
I designed a mosfet-based DC switch, but it\'s complex.

A big triac is a possibility. I could drive that with just a switch
and maybe a fusable resistor from anode to gate. That would put AC
line voltage on the little switch up front.

Maybe tiny power supply, DC switch, opto SSR, triac.

There would still be a giant, in practice inaccessable, switch on the
power inlet on the back.

Triac gives you the option of a slow start and reduced inrush current,
either by starting on a zero crossing of the mains
or simply slowly increase firing angle.
Does not have to be a very complex driver circuit.

I do have several Meanwell in series, have 5 of those.
Mains fuse never blew, but at 230 V current is half of what you have over there.
Also one on all day at 7 V.
These things are reliable so far.

If in series backward diodes?

--- + --------------- 0 / 12 or 24 V (depending how many on)
|
___
12V / \\
--- Schottky
|
--- - ----
|
--- + ----
|
___
12V / \\
---
|
--- - ----

Dunno how accurate it needs to be..

 

[legg]

On Thu, 03 Sep 2020 09:44:39 -0700, jlarkin@highlandsniptechnology.com
wrote:

I\'m thinking about a big new box, with three universal-input power
supplies in the back. The customer wants a power switch on the front.

I guess I can just run the AC through the switch. But that\'s big ugly,
maybe noisy wiring, and such switches tend to fail from inrush surge.

Surge might be fixed with an NTC current limiter.

I could switch the input AC with a big relay in the back. But where
would I get the power to do that? I\'d need a power relay whose coil
operates from 100 to 240 volts.

Or switch the DC supply outputs with some mosfets.

Digikey has some small universal-input DC supplies, 12 or 24 VDC out,
for around $10. One of those could power the relay or the mosfet
circuit.

There would probably be a real power switch on the AC inlet/filter
brick; this would be a \"soft\" power switch.

Do modern PFC-corrected power supplies have big input current surges?
Gotta find out.

Any suggestions?

Perhaps a single AC-365vdc PFC front end, feeding your many supplies.

The PFC section will allow for a normal line switch, emi and inrush
spec. Some may have an isolated enable line for soft I/O control.

A universal input power supply may react unexpectedly with the DC
input - you\'d have to check it out. As long as some protective circuit
isn\'t activated, any input pfc section should just feed-through.

Downstream inverters and housekeepers will be expecting the voltage
supplied. As you\'re not synchronizing your units, I don\'t imagine
the noise from the separate conversion stage will make much difference
to the flora and fauna.

Something like a Cosel DPG750
or on ebay
https://www.ebay.com/itm/Input-AC-100-240V-Output-DC-385V-300-500W-OPS-U-500-385-/180805702201

Or an AC-48V converter to run different DC-DC converters with 48V
input.

RL

 

[Jan Panteltje]

PS
about switches that are immune to bumping into
google \'locking toggle switch\'.
Something like this
https://www.steinair.com/product/locking-toggle-switch-spst-onoff/
but then cheaper...

 

[Fred Bloggs]

On Thursday, September 3, 2020 at 12:44:54 PM UTC-4, jla...@highlandsniptechnology.com wrote:

I\'m thinking about a big new box, with three universal-input power
supplies in the back. The customer wants a power switch on the front.

I guess I can just run the AC through the switch. But that\'s big ugly,
maybe noisy wiring, and such switches tend to fail from inrush surge.

Surge might be fixed with an NTC current limiter.

I could switch the input AC with a big relay in the back. But where
would I get the power to do that? I\'d need a power relay whose coil
operates from 100 to 240 volts.

Or switch the DC supply outputs with some mosfets.

Digikey has some small universal-input DC supplies, 12 or 24 VDC out,
for around $10. One of those could power the relay or the mosfet
circuit.

There would probably be a real power switch on the AC inlet/filter
brick; this would be a \"soft\" power switch.

Do modern PFC-corrected power supplies have big input current surges?
Gotta find out.

Any suggestions?



--

John Larkin Highland Technology, Inc

EATON makes a line of high inrush power switches rated for up to 100A and good for 20,000 actuations, tested against switch bounce during the inrush, guaranteed to avoid arc welding or otherwise damaging the contacts. They last forever and don\'t cost that much. Form factor is panel mount, an automation industry gizmo. You have to register with EATON to see the details so that\'s where I stop.

 

[John Larkin]

A 50 amp relay costs $3. Maybe I\'ll just switch the AC into the
supplies. All I need is coil voltage.


Pity; I design a elegant mosfet-based output switch.


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WIRE -192 448 -192 144
WIRE 560 448 560 416
WIRE -1312 464 -1440 464
WIRE -1040 480 -1040 384
WIRE -880 480 -880 384
WIRE -688 480 -688 432
WIRE -560 480 -688 480
WIRE 64 480 64 400
WIRE 224 480 224 400
WIRE 368 480 368 416
WIRE -432 496 -496 496
WIRE -400 496 -432 496
WIRE -256 496 -320 496
WIRE 880 496 848 496
WIRE 944 496 880 496
WIRE 1104 496 1024 496
WIRE 1408 496 1408 416
WIRE 1408 496 1200 496
WIRE -1440 512 -1440 464
WIRE -1232 512 -1232 384
WIRE 1584 512 1584 256
WIRE -1312 528 -1312 464
WIRE -1280 528 -1312 528
WIRE -688 544 -688 480
WIRE -1280 576 -1312 576
WIRE 560 576 560 528
WIRE 1408 592 1408 496
WIRE 1536 592 1408 592
WIRE -1040 608 -1040 544
WIRE -880 608 -880 560
WIRE -1312 624 -1312 576
WIRE -1232 624 -1232 592
WIRE -1232 624 -1312 624
WIRE 1152 624 1152 560
WIRE 1408 640 1408 592
WIRE -1440 656 -1440 592
WIRE -1232 656 -1232 624
WIRE -192 656 -192 544
WIRE -96 656 -192 656
WIRE -688 672 -688 624
WIRE -96 688 -96 656
WIRE 384 704 224 704
WIRE 528 704 464 704
WIRE 592 704 528 704
WIRE -192 752 -192 656
WIRE 1152 784 1104 784
WIRE 1216 784 1152 784
WIRE 1408 784 1408 720
WIRE 1408 784 1296 784
WIRE 1584 784 1584 608
WIRE 1584 784 1408 784
WIRE 224 816 224 704
WIRE -1232 896 -1296 896
WIRE -1200 896 -1232 896
WIRE -992 896 -1056 896
WIRE -960 896 -992 896
WIRE -752 896 -816 896
WIRE -720 896 -752 896
WIRE -480 896 -512 896
WIRE -432 896 -480 896
WIRE -192 896 -192 816
WIRE -192 896 -336 896
WIRE 48 896 -192 896
WIRE 176 896 48 896
WIRE -1296 928 -1296 896
WIRE -1056 928 -1056 896
WIRE -816 928 -816 896
WIRE -336 976 -336 896
WIRE 48 976 48 896
WIRE -432 992 -432 896
WIRE -384 992 -432 992
WIRE -192 992 -192 896
WIRE -1296 1040 -1296 1008
WIRE -1056 1040 -1056 1008
WIRE -816 1040 -816 1008
WIRE -384 1040 -432 1040
WIRE -432 1136 -432 1040
WIRE -336 1136 -336 1056
WIRE -192 1136 -192 1056
WIRE -192 1136 -336 1136
WIRE 48 1136 48 1056
WIRE 48 1136 -192 1136
WIRE 224 1136 224 912
WIRE 224 1136 48 1136
WIRE 368 1136 224 1136
WIRE 512 1136 368 1136
WIRE 592 1136 512 1136
WIRE 224 1216 224 1136
WIRE 368 1216 368 1136
WIRE 224 1360 224 1280
WIRE 368 1360 368 1296
FLAG -1296 1040 0
FLAG -1232 896 +12
FLAG -1056 1040 0
FLAG -992 896 -12
FLAG -816 1040 0
FLAG -752 896 +5
FLAG -64 -48 +5
FLAG 624 256 5SW
FLAG 64 480 0
FLAG 224 480 0
FLAG 368 480 0
FLAG 560 576 0
FLAG 624 416 Ipv
FLAG 528 704 +12
FLAG 512 1136 12SW
FLAG 224 1360 0
FLAG 368 1360 0
FLAG -432 1136 0
FLAG -480 896 Ipv
FLAG -96 688 0
FLAG 1680 256 -12SW
FLAG 1200 32 0
FLAG 1152 784 -12
FLAG 1152 624 0
FLAG 880 496 5SW
FLAG -688 672 0
FLAG -656 272 +5
FLAG -880 608 0
FLAG -912 144 +12
FLAG -1232 656 0
FLAG -1440 656 0
FLAG -1040 608 0
FLAG -432 496 R+
SYMBOL nmos 176 64 R0
WINDOW 0 137 41 Left 2
WINDOW 3 74 71 Left 2
SYMATTR InstName M1
SYMATTR Value FDB045AN08A0
SYMBOL res -336 128 R90
WINDOW 0 72 54 VBottom 2
WINDOW 3 85 55 VTop 2
SYMATTR InstName R1
SYMATTR Value 10K
SYMBOL voltage -1296 912 R0
WINDOW 0 57 50 Left 2
WINDOW 3 57 83 Left 2
SYMATTR InstName V1
SYMATTR Value 12
SYMBOL voltage -1056 912 R0
WINDOW 0 57 50 Left 2
WINDOW 3 57 83 Left 2
SYMATTR InstName V2
SYMATTR Value -12
SYMBOL voltage -816 912 R0
WINDOW 0 57 50 Left 2
WINDOW 3 57 83 Left 2
SYMATTR InstName V3
SYMATTR Value 5
SYMBOL cap 48 336 R0
WINDOW 0 -84 17 Left 2
WINDOW 3 -83 50 Left 2
SYMATTR InstName C1
SYMATTR Value 1µ
SYMBOL cap 208 336 R0
WINDOW 0 -67 14 Left 2
WINDOW 3 -67 55 Left 2
SYMATTR InstName C2
SYMATTR Value 1m
SYMBOL res 352 320 R0
WINDOW 0 62 44 Left 2
WINDOW 3 60 77 Left 2
SYMATTR InstName R2
SYMATTR Value 0.2
SYMBOL diode 544 320 R0
WINDOW 0 65 -8 Left 2
WINDOW 3 70 24 Left 2
SYMATTR InstName D1
SYMBOL res 544 432 R0
WINDOW 0 -69 77 Left 2
WINDOW 3 -67 108 Left 2
SYMATTR InstName R3
SYMATTR Value 1K
SYMBOL nmos 176 816 R0
WINDOW 0 137 41 Left 2
WINDOW 3 74 71 Left 2
SYMATTR InstName M2
SYMATTR Value FDB045AN08A0
SYMBOL res 32 960 R0
WINDOW 0 63 45 Left 2
WINDOW 3 48 76 Left 2
SYMATTR InstName R4
SYMATTR Value 250K
SYMBOL cap 208 1216 R0
WINDOW 0 -63 32 Left 2
WINDOW 3 -63 67 Left 2
SYMATTR InstName C4
SYMATTR Value 1m
SYMBOL res 352 1200 R0
WINDOW 0 65 38 Left 2
WINDOW 3 69 67 Left 2
SYMATTR InstName R5
SYMATTR Value 2
SYMBOL zener -176 1056 R180
WINDOW 0 -77 48 Left 2
WINDOW 3 -168 10 Left 2
SYMATTR InstName D2
SYMATTR Value BZX84B8V2L
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL g -336 960 R0
WINDOW 0 55 33 Left 2
WINDOW 3 51 68 Left 2
SYMATTR InstName G1
SYMATTR Value 10µ
SYMBOL cap -208 752 R0
WINDOW 0 -67 19 Left 2
WINDOW 3 -71 52 Left 2
SYMATTR InstName C3
SYMATTR Value 10n
SYMBOL nmos 1536 512 R0
WINDOW 0 137 41 Left 2
WINDOW 3 74 71 Left 2
SYMATTR InstName M3
SYMATTR Value FDB045AN08A0
SYMBOL res 1392 624 R0
WINDOW 0 64 51 Left 2
WINDOW 3 64 83 Left 2
SYMATTR InstName R6
SYMATTR Value 2K
SYMBOL cap 1392 352 R0
WINDOW 0 -73 8 Left 2
WINDOW 3 -68 44 Left 2
SYMATTR InstName C5
SYMATTR Value 1µ
SYMBOL res 1568 32 R0
WINDOW 0 65 38 Left 2
WINDOW 3 69 67 Left 2
SYMATTR InstName R7
SYMATTR Value 2
SYMBOL cap 1392 48 R0
WINDOW 0 -63 32 Left 2
WINDOW 3 -63 67 Left 2
SYMATTR InstName C6
SYMATTR Value 1m
SYMBOL pnp 1200 560 M270
WINDOW 0 145 61 VLeft 2
WINDOW 3 102 87 VLeft 2
SYMATTR InstName Q1
SYMATTR Value 2N4403
SYMBOL res 1040 480 R90
WINDOW 0 82 56 VBottom 2
WINDOW 3 99 55 VTop 2
SYMATTR InstName R8
SYMATTR Value 1K
SYMBOL Digital\\\\schmitt -560 416 R0
WINDOW 0 56 120 Left 2
SYMATTR InstName A1
SYMATTR SpiceLine VHIGH=5 VLOW=0
SYMATTR SpiceLine2 VT=4 VH=0.2
SYMBOL npn -752 336 R0
WINDOW 0 105 22 Left 2
WINDOW 3 78 62 Left 2
SYMATTR InstName Q2
SYMATTR Value 2N4401
SYMBOL res -704 528 R0
WINDOW 0 61 44 Left 2
WINDOW 3 60 74 Left 2
SYMATTR InstName R9
SYMATTR Value 10K
SYMBOL res -896 464 R0
WINDOW 0 61 32 Left 2
WINDOW 3 62 67 Left 2
SYMATTR InstName R10
SYMATTR Value 10K
SYMBOL res -896 208 R0
WINDOW 0 -96 40 Left 2
WINDOW 3 -97 76 Left 2
SYMATTR InstName R11
SYMATTR Value 10K
SYMBOL cap -1056 480 R0
WINDOW 0 61 18 Left 2
WINDOW 3 63 54 Left 2
SYMATTR InstName C7
SYMATTR Value 1µ
SYMBOL sw -1232 496 R0
WINDOW 0 54 43 Left 2
WINDOW 3 54 78 Left 2
SYMATTR InstName S2
SYMATTR Value SP
SYMBOL voltage -1440 496 R0
WINDOW 0 44 169 Left 2
WINDOW 3 -23 215 Left 2
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V5
SYMATTR Value PULSE(-1 1 10m 0 0 250m)
SYMBOL res 112 -64 R90
WINDOW 0 77 54 VBottom 2
WINDOW 3 88 55 VTop 2
SYMATTR InstName R12
SYMATTR Value 1m
SYMBOL res 480 688 R90
WINDOW 0 77 54 VBottom 2
WINDOW 3 88 55 VTop 2
SYMATTR InstName R13
SYMATTR Value 1m
SYMBOL res 1312 768 R90
WINDOW 0 77 54 VBottom 2
WINDOW 3 88 55 VTop 2
SYMATTR InstName R14
SYMATTR Value 1m
SYMBOL res -304 480 R90
WINDOW 0 72 54 VBottom 2
WINDOW 3 85 55 VTop 2
SYMATTR InstName R15
SYMATTR Value 10K
SYMBOL npn -256 448 R0
WINDOW 0 105 22 Left 2
WINDOW 3 78 62 Left 2
SYMATTR InstName Q3
SYMATTR Value 2N4401
TEXT 280 168 Left 2 ;FDD86367
TEXT 816 1184 Left 2 !.tran 500m
TEXT 816 1232 Left 2 !.model SP SW(Ron=.1 Roff=1Meg Vt=0 )
TEXT 480 88 Left 2 ;5V SWITCH
TEXT 400 432 Left 2 ;Load
TEXT 600 456 Left 2 ;PV Opto
TEXT 280 920 Left 2 ;FDD86367
TEXT 440 992 Left 2 ;12V SWITCH
TEXT 400 1296 Left 2 ;Load
TEXT -128 944 Left 2 ;PV Opto
TEXT 904 1000 Left 3 ;Crate Power Switch
TEXT 952 1064 Left 2 ;JL Sep 5 2020
TEXT 1624 136 Left 2 ;Load
TEXT -1192 608 Left 2 ;POWER
TEXT -1192 640 Left 2 ;SWITCH
TEXT -528 568 Left 2 ;STM810
TEXT 1640 624 Left 2 ;FDD86367
TEXT 1112 328 Left 2 ;-12 SWITCH















--

John Larkin Highland Technology, Inc trk

The cork popped merrily, and Lord Peter rose to his feet.
\"Bunter\", he said, \"I give you a toast. The triumph of Instinct over Reason\"

 

[Phil Hobbs]

On 2020-09-07 11:14, John Larkin wrote:

A 50 amp relay costs $3. Maybe I\'ll just switch the AC into the
supplies. All I need is coil voltage.

You can get zero-voltage switching SSRs as well, e.g.

AQJ116V Panasonic SSR RELAY SPST-NO 10A 75-264V $18.08000 @ qty 100

That\'ll prevent the Romex in the walls going thump when you turn on the
box, too.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[John Larkin]

On Mon, 7 Sep 2020 12:12:29 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-09-07 11:14, John Larkin wrote:
A 50 amp relay costs $3. Maybe I\'ll just switch the AC into the
supplies. All I need is coil voltage.



You can get zero-voltage switching SSRs as well, e.g.

AQJ116V Panasonic SSR RELAY SPST-NO 10A 75-264V $18.08000 @ qty 100

That\'ll prevent the Romex in the walls going thump when you turn on the
box, too.

Cheers

Phil Hobbs

I\'d be concerned about the 180 amp inrush melting a 10-amp SSR. The
first quarter cycle might be bad.

I\'d have thought that people would make SSRs with a contact closure
input, but I haven\'t found any. They all need \"coil\" voltage.

We used to make CAMAC crates that had a giant transformer, and if you
got unlucky with the power switch, you could literally hear the romex
thump in the wall. An NTC thermistor fixed that. I expected cool-down
time constant problems but never saw any.

I guess I could switch the DC outputs with three relays.



--

John Larkin Highland Technology, Inc trk

The cork popped merrily, and Lord Peter rose to his feet.
\"Bunter\", he said, \"I give you a toast. The triumph of Instinct over Reason\"

 

[Phil Hobbs]

On 2020-09-07 12:33, John Larkin wrote:

On Mon, 7 Sep 2020 12:12:29 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-09-07 11:14, John Larkin wrote:
A 50 amp relay costs $3. Maybe I\'ll just switch the AC into the
supplies. All I need is coil voltage.



You can get zero-voltage switching SSRs as well, e.g.

AQJ116V Panasonic SSR RELAY SPST-NO 10A 75-264V $18.08000 @ qty 100

That\'ll prevent the Romex in the walls going thump when you turn on the
box, too.

Cheers

Phil Hobbs

I\'d be concerned about the 180 amp inrush melting a 10-amp SSR. The
first quarter cycle might be bad.

I\'d have thought that people would make SSRs with a contact closure
input, but I haven\'t found any. They all need \"coil\" voltage.

We used to make CAMAC crates that had a giant transformer, and if you
got unlucky with the power switch, you could literally hear the romex
thump in the wall. An NTC thermistor fixed that. I expected cool-down
time constant problems but never saw any.

I guess I could switch the DC outputs with three relays.

There wouldn\'t be that big an inrush, surely? If it\'s 200A at the sine
wave peak, it would be considerably less near zero. The hold-up time of
the supply is only one cycle of 60 Hz at full load, so the
zero-volt-switched inrush would be about 2x the average current. The
one-cycle nonrepetitive surge current rating for that one is 100A, which
I\'d think would be lots.

(They make 250A surge-rated SSRs in the same series.)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Chris]

On 09/07/20 17:33, John Larkin wrote:

On Mon, 7 Sep 2020 12:12:29 -0400, Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote:

On 2020-09-07 11:14, John Larkin wrote:
A 50 amp relay costs $3. Maybe I\'ll just switch the AC into the
supplies. All I need is coil voltage.



You can get zero-voltage switching SSRs as well, e.g.

AQJ116V Panasonic SSR RELAY SPST-NO 10A 75-264V $18.08000 @ qty 100

That\'ll prevent the Romex in the walls going thump when you turn on the
box, too.

Cheers

Phil Hobbs

I\'d be concerned about the 180 amp inrush melting a 10-amp SSR. The
first quarter cycle might be bad.

I\'ve found specified inrush currents to be worst case and wildly
over the top in general.

The only way to specify is to measure it on a scope + percentage,
otherwise you\'ll over engineer the solution.

I\'d have thought that people would make SSRs with a contact closure
input, but I haven\'t found any. They all need \"coil\" voltage.

We used to make CAMAC crates that had a giant transformer, and if you
got unlucky with the power switch, you could literally hear the romex
thump in the wall. An NTC thermistor fixed that. I expected cool-down
time constant problems but never saw any.

I guess I could switch the DC outputs with three relays.

One relay driven by three diodes in an and config so that all psus
must be pok to enable the outputs ?...

Chris