115/230V voltage switch key for transformer?

[Joerg]

Hello Folks,

Never needed this before but now I do: What are those things called that
you unplug and insert 180 degrees rotated to switch the primaries of a
transformer between 115V operation (parallel) and 230V operation
(series)? Circuit board mount.

Or better yet, does anyone know a source? Must be super cheap, as in
<<50c altogether in qties, as usual

Under categories such as "voltage selector" I only found fuse holders
with this feature in there, really expensive plus way too large. I want
to avoid a slide switch because someone could accidentally hit it and
.... *PHUT*

 

[Joerg]

The classic term used in Marshall and other Audio Amps is voltage
selector plug.

Somebody decided they should be removed from the electrical code. ...

Ouch, ouch, ouch ... really? So they are gone for good?

... Your left with the voltage selecting fuseholders. try schurter.

Those are all way too expensive plus this has to fit onto a circuit
board. The fuse holders are large panel mount devices but we'll have no
panel.

I could cook up an electronic auto-selector but that would probably blow
the cost target as well.

 

[petrus bitbyter]

<[email protected]> schreef in bericht

Hello Folks,

Never needed this before but now I do: What are those things called that
you unplug and insert 180 degrees rotated to switch the primaries of a
transformer between 115V operation (parallel) and 230V operation
(series)? Circuit board mount.

Or better yet, does anyone know a source? Must be super cheap, as in
<<50c altogether in qties, as usual

Under categories such as "voltage selector" I only found fuse holders
with this feature in there, really expensive plus way too large. I want
to avoid a slide switch because someone could accidentally hit it and
... *PHUT*

| The classic term used in Marshall and other Audio Amps is voltage
| selector plug.
|
| Somebody decided they should be removed from the electrical code. Your
| left with the voltage selecting fuseholders. try schurter.
|
| Steve
|

FAIK that old method does not meet current EU safety regulations anymore. So
that selectors became obsolete.

Why a slide switch will not do? You can find voltage selector slide switches
in which the slider is burried so deeply it can only be operated by a small
screwdriver or something like that. Sliding it accidentaly seems next to
impossible.

petrus bitbyter

 

[Rich Grise]

Hello Folks,

Never needed this before but now I do: What are those things called that
you unplug and insert 180 degrees rotated to switch the primaries of a
transformer between 115V operation (parallel) and 230V operation (series)?
Circuit board mount.

Or better yet, does anyone know a source? Must be super cheap, as in <<50c
altogether in qties, as usual

Under categories such as "voltage selector" I only found fuse holders with
this feature in there, really expensive plus way too large. I want to
avoid a slide switch because someone could accidentally hit it and ...
*PHUT*

Jumper?

Good Luck!
Rich

 

[Joerg]

The cost is driven up on the fuse holders because the main use is
medical.

Yup.


Go here:

http://www.onsemi.com/pub/Collateral/HBD855-D.PDF

Page 174 for a triac autoswitcher that will probably come in a little
less then the fuseholder, but not much.

That's quite a ghastly solution. It requires an additional control
transformer and its miscellanea to feed the detectors, plus it requires
one of the primary halves to be strong enough to stomach the whole input
current when at 115V. Which most transformers can't do.

Rant Mode:
If your angry about this:

Then admonish all the folks who voted for the EU a decade or two ago
that y'all got us into this mess of changing regulations from Brussels
messing up the electronics industry status quo. I being a USian, had
no say in the matter. I like 60 hz center tapped transformers, I like
60/40 and I like incandescent bulbs in my machine shop for safety
reasons. I'm now told I can't have any of the above. And worse, now I
need 5,000$ worth of testing for a battery pack in a month, plus . I
have send them 26 battery packs at 200$ a pack for the test. I have
a special place in my heart for that bastard said lead leaches. Well,
so does everything else.
END RANT MODE.

One of my clients decided to just cut the EU market off many years ago,
at least for a while. Seriously. It is also one reason why stuff is
often so much more expensive over there because bureaucratic hurdle
costs get factored into the price.

 

[Joerg]

<[email protected]> schreef in bericht


| The classic term used in Marshall and other Audio Amps is voltage
| selector plug.
|
| Somebody decided they should be removed from the electrical code. Your
| left with the voltage selecting fuseholders. try schurter.
|
| Steve
|

FAIK that old method does not meet current EU safety regulations anymore. So
that selectors became obsolete.

Why a slide switch will not do? You can find voltage selector slide switches
in which the slider is burried so deeply it can only be operated by a small
screwdriver or something like that. Sliding it accidentaly seems next to
impossible.

Not that easy anymore. Slide switches often don't have the respective
agency ratings and since they are primary side they must. Also, it is
very hard to find any that are rated 260V which is required for
countries such as the UK.

 

[Joerg]

Jumper?

Very much against code, usually. Unless it's a wire jumper but my client
wants to avoid having to open the units every time an order comes in for
the "wrong" voltage.

 

[Joerg]

Yeah, the ON circuit is crude, and the SCRs in series are a failure
point. But its a start.
And from a safety point of view, its got to be more of a hazard then a
properly made jumper.
Kinda my point.

I take it this is on a linear for noise or cost reasons?

Two reasons. The cost of transformers is remarkably low, around five
bucks for 10-15VA. Can't beat that with a switcher, even considering
your own PWM stuff behind it because that only adds a buck or two.

Then, temperature. Beats me but all the places I've called won't endorse
more than 50C or 60C for their switcher modules and that's just not
going to fly. For some reason my own designs never had such limits but I
can't justify the NRE for all the agency testing on this one if we
rolled our own mains-connected switcher.

The only 250V-rated selectors I see are panel mount and insanely
expensive, such as this one:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=0033.1118-ND

 

[krw]

Two reasons. The cost of transformers is remarkably low, around five
bucks for 10-15VA. Can't beat that with a switcher, even considering
your own PWM stuff behind it because that only adds a buck or two.

Then, temperature. Beats me but all the places I've called won't endorse
more than 50C or 60C for their switcher modules and that's just not
going to fly. For some reason my own designs never had such limits but I
can't justify the NRE for all the agency testing on this one if we
rolled our own mains-connected switcher.

The only 250V-rated selectors I see are panel mount and insanely
expensive, such as this one:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=0033.1118-ND

How about a wall wart? You should be able to find something like that
for $10-$15.

 

[Joerg]

How about a wall wart? You should be able to find something like that
for $10-$15.

The only way to get one in would be to snip the end off a two-prong
Christmas extension code, solder it in and strap the whole kludge down
with cable ties. Any fire marshall would blow a gasket ;-)

Plus I think wall warts don't like to bake in there.

 

[Rich Grise]

Not that easy anymore. Slide switches often don't have the respective
agency ratings and since they are primary side they must. Also, it is very
hard to find any that are rated 260V which is required for countries such
as the UK.

Don't PC power supplies have these? If so, then _somebody_ is making
millions of them, and they can't be terribly expensive.

Another thing - if it's inside the case, (i.e., soldered to the PCB),
couldn't you put a "No User-Sericeable Parts Inside" sticker, and just
set an ordinary slide switch or jumper at the factory?

I once worked at a battery charger manufacturer, and the boss had
"designed" a circuit that would automatically switch, depending on what
you plugged it into. - a relay, a diode, a cap and a couple of resistors.
If you plugged it into 120, the relay didn't pull in, but if you plugged
it into 240, the relay pulled in and switched the primaries.

But that's a little parts-intensive, and you're not expecting pathological
operating conditions, right?

Thanks,
Rich

 

[Joerg]

What exactly is it you're trying to produce? You've given several
different conflicting scenarios here. Is the user supposed to be
responsible for selecting the voltage? Does it get set at the factory?
What code are you trying to satisfy?

Please, Joerg, tell us the "big picture" here.

Ok, big picture follows:

Unit in fields, outdoors, think farm. The sun is pelting it brutally all
day long and the electric stuff sits inside an enclosure, no vents big
enough to write home about. No choice, it has to be that way and it
works fine in a 120V version.

Client wants users to be able to ideally just plug it into 120 or 240,
and not worry about a thing. That ain't going to fly because SMPS
modules seem to not be that great. Maybe cheap electrolytics, I don't
know, but mfgs don't want to endorse >60C and it sure does get hotter
than that in there. Just by the sun.

So, the next best avenue would be a configurable 120/240 transformer
because then we can have our own (better) switcher behind that.
Unfortunately the cheap voltage selectors have become pariahs.

Configuring at the factory would be ok but it has to be simple, like
flicking a hidden switch or reversing an insert. But it (meaning also
that switching element) must be code-compliant, in this case UL as well
as VDE (CE) plus later some others, maybe Japan. Up to now it was only UL.

Cost is critical. Adding a buck in total is ok, adding five bucks is not.

BTW, how do you pronounce "Joerg?"

It's o-umlaut, pronounced just like Archie Bunker and many New Yorkers
say "poifect" or "point".

 

[Fred Bartoli]

Joerg a écrit :

Ok, big picture follows:

Unit in fields, outdoors, think farm. The sun is pelting it brutally all
day long and the electric stuff sits inside an enclosure, no vents big
enough to write home about. No choice, it has to be that way and it
works fine in a 120V version.

Client wants users to be able to ideally just plug it into 120 or 240,
and not worry about a thing. That ain't going to fly because SMPS
modules seem to not be that great. Maybe cheap electrolytics, I don't
know, but mfgs don't want to endorse >60C and it sure does get hotter
than that in there. Just by the sun.

So, the next best avenue would be a configurable 120/240 transformer
because then we can have our own (better) switcher behind that.
Unfortunately the cheap voltage selectors have become pariahs.

Configuring at the factory would be ok but it has to be simple, like
flicking a hidden switch or reversing an insert. But it (meaning also
that switching element) must be code-compliant, in this case UL as well
as VDE (CE) plus later some others, maybe Japan. Up to now it was only UL.

Cost is critical. Adding a buck in total is ok, adding five bucks is not.

Have a dual 120V primaries xfrmer with a relay switched series/parallel
connection.
The relay rest position is connecting the xfrmer in 240V mode, then you
have all the time you need to decide what to do with the relay.
Cost: one relay and 10c parts.

But I'm confident you'll find something that won't fit ;-)

 

[Joerg]

Joerg a écrit :

Have a dual 120V primaries xfrmer with a relay switched series/parallel
connection.
The relay rest position is connecting the xfrmer in 240V mode, then you
have all the time you need to decide what to do with the relay.
Cost: one relay and 10c parts.

But I'm confident you'll find something that won't fit ;-)

Yeah, two things :-(

One, a primary side relay adds more than those 10 cents. The other is
that a brown-out situation would cause the relay to partially let go ...
bzzz ... phssss ... *PHOOMP*

Of course I could make a brown-out detector and all that. But things
would need to go fast because the transformer is without power during
the switch-over.

Did you decide which theremin to build with your daughter?

 

[Joerg]

Don't PC power supplies have these? If so, then _somebody_ is making
millions of them, and they can't be terribly expensive.

Yes, sometimes, but as usual, integrated into the IEC connector. Can't
use that, no space.

Another thing - if it's inside the case, (i.e., soldered to the PCB),
couldn't you put a "No User-Sericeable Parts Inside" sticker, and just
set an ordinary slide switch or jumper at the factory?

I once worked at a battery charger manufacturer, and the boss had
"designed" a circuit that would automatically switch, depending on what
you plugged it into. - a relay, a diode, a cap and a couple of resistors.
If you plugged it into 120, the relay didn't pull in, but if you plugged
it into 240, the relay pulled in and switched the primaries.

But that's a little parts-intensive, and you're not expecting pathological
operating conditions, right?

Well, there will be sluggish brown-outs and the like.

 

[Fred Bartoli]

Joerg a écrit :

Yeah, two things :-(

One, a primary side relay adds more than those 10 cents.

You said 1 buck is OK, not five.
I said one relay and 10c parts. I guess that would not make for 5 bucks...

The other is

that a brown-out situation would cause the relay to partially let go ...
bzzz ... phssss ... *PHOOMP*

Of course I could make a brown-out detector and all that. But things
would need to go fast because the transformer is without power during
the switch-over.

But don't you have a bulk cap somewhere?
Just keep the relay in the same state until the bulk cap voltage is
over. And if you use a low voltage coil WRT to the nominal bulk cap
rail, then you have plenty brownout time before the relay decides to
switch back.

Oh, and it'll never switch on 240 mains, so in not 3rd world countries
we won't experience any failure at all.

Did you decide which theremin to build with your daughter?

Not yet, but I got some bit of interesting info I didn't think about,
like the one (it's all about ergonomic) that use some "linearizing
trick" to get a usable hand stroke. But I don't like the way they do it
(1000s turns coil).
Also the one you pointed me too was already preassembled. Just fit it in
the box and voilà. That's not what I was after.
But now I begin to feel I've the info I missed to design a good one, so
I might go that path.

Of course work will get in the way, but...

 

[Baron]

Not that easy anymore. Slide switches often don't have the respective
agency ratings and since they are primary side they must. Also, it is
very hard to find any that are rated 260V which is required for
countries such as the UK.

Dunno if it helps, I've seen multi pole jumpers used for voltage
selection where the cap has multiple links in it.

 

[Rich Grise]

It's o-umlaut, pronounced just like Archie Bunker and many New Yorkers say
"poifect" or "point".

"Joig?" Or maybe "Yoig?"

If "Euler" is pronounced, "Oiler," then howcome "Euclid" isn't pronounced
"Oiclid?" ;-)

Thanks,
Rich

 

[Rich Grise]

"Joig?" Or maybe "Yoig?"

If "Euler" is pronounced, "Oiler," then howcome "Euclid" isn't pronounced
"Oiclid?" ;-)

PS. I was thinking maybe "Yerg". ;-)

Oops - I think the vodka might be kicking in...

Thanks,
Rich

 

[Herman]

Ok, big picture follows:

Unit in fields, outdoors, think farm. The sun is pelting it brutally all
day long and the electric stuff sits inside an enclosure, no vents big
enough to write home about. No choice, it has to be that way and it works
fine in a 120V version.

Client wants users to be able to ideally just plug it into 120 or 240, and
not worry about a thing. That ain't going to fly because SMPS modules seem
to not be that great. Maybe cheap electrolytics, I don't know, but mfgs
don't want to endorse >60C and it sure does get hotter than that in there.
Just by the sun.

So, the next best avenue would be a configurable 120/240 transformer
because then we can have our own (better) switcher behind that.
Unfortunately the cheap voltage selectors have become pariahs.

Configuring at the factory would be ok but it has to be simple, like
flicking a hidden switch or reversing an insert. But it (meaning also that
switching element) must be code-compliant, in this case UL as well as VDE
(CE) plus later some others, maybe Japan. Up to now it was only UL.

Cost is critical. Adding a buck in total is ok, adding five bucks is not.



It's o-umlaut, pronounced just like Archie Bunker and many New Yorkers say
"poifect" or "point".

See if this will work for you.
http://s936.photobucket.com/albums/ad204/rike2/