Jon Anderson writes:

On 8/10/2011 6:06 PM, Michael A. Terrell wrote:

Sigh. That 'Toroid' is wound from steel tape. You can't make a
decent 50 or 60 Hz transformer without it.

sheepish grin Well, I've never cut one apart, so didn't know. Can't
SEE any steel... G


Some are ferrite iron power imbedded in the donut, but trust me,
it's got something magnetic....


--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

On Monday, August 8, 2011 8:12:42 PM UTC-4, Pete C. wrote:
Jon Anderson wrote:

Ok, thought I'd spelled it out, but didn't. Here's the blade welder specs:

220 volts

No issue.

20 amp

No issue.

60 Hz

Issue since OZ power is 50 Hz. For a short duty cycle item like a blade
welder you will *probably* be ok.

This is probably just a matter for careful selection of a circuit breaker.
Transformers have a volt-second limit (and that means 50 Hz at rated
voltage is more likely to saturate the core than 60 Hz at rated voltage).
The volt-second limit applies to the UNLOADED transformer, though,
so a blade-welding cycle (with a nice big load on the secondary
while current is flowing in the work) is likely to be trouble-free.
If the transformer is switched on before the blade parts are butted,
it could saturate and blow the main breaker (so putting a 20A breaker
local to the unit would be more convenient if it needs resetting).

Another saturation protection would be a good fast-blow fuse (because
if it isn't the breaker or fuse that blows, it's the copper in the transformer).

On Wednesday, August 10, 2011 10:47:40 PM UTC-4, Jon Anderson wrote:
Ok, have finally found something workable, if not cheap.
There's a company that makes isolated step down transformers using
toroidal transformers. No iron core to get hot!

Isolation is expensive and unnecessary. You can use a simple bucking transformer
(the 240V 60 Hz rating of a US transformer for saturation of the core
corresponds to 200V 50 Hz rating) that lowers 220V to 200V.

Of course, 'toroidal' refers to the shape, it still has an iron core.

On Wednesday, August 10, 2011 9:15:19 PM UTC-4, Jon Anderson wrote:
On 8/10/2011 3:22 PM, David Lesher wrote:

Oh, an important exception or two. MANY power supplies for computers
and entertainment gadgets are "switchers".

Let me tell you, that's one HELL of a bang when a 110 PS gets socked
with 220!

Most modern computer supplies either have a switch, or autoswitch. I
haven't seen a '110 PS' in decades. Some, which use a manual switch,
have a hard-to-get-to fuse. The fuse can pop, loud.

Ned Simmons writes:


The furnace in question probably runs over $1000 new. A new
transformer large enough to power it would be less than $200. I sold a
couple used weatherproof 15kVA 480/240 to 240/120 transformers
recently, and was glad to get around $100 each for them.

Were those 60 or 50 Hz ones? I think he'll have a hard time getting
a 50Hz transformer there of sufficent size.
--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

On 8/11/2011 1:14 PM, whit3rd wrote:

Most modern computer supplies either have a switch, or autoswitch. I
haven't seen a '110 PS' in decades. Some, which use a manual switch,
have a hard-to-get-to fuse. The fuse can pop, loud.

Actually, I did state that I forgot to switch this one. It was a
110/220, and I just plain got distracted and forgot to move the slider.
Won't make that mistake again... And it wasn't a fuse that went, I
opened it up hoping to find a fuse. Think it was a cap that blew.
The noise was close to a firecracker. I've never heard a fuse do that,
which is not to say they can't.


Jon

Ned Simmons writes:


The furnace in question probably runs over $1000 new. A new
transformer large enough to power it would be less than $200.

I can't find the post describing it, but if this oven is just resistive,
frequency does not matter, period.

And it may be possible to get 240V heaters for it to replace the 120V.
There may some other ugly hack possible; put a another resistive
heater of the same load in series, etc.

--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

Copper takes 100% overload for a long time. In power distribution systems
hours..it can glow read hot and still survive just fine.

Aluminum is a different beast.

---------------

"whit3rd" wrote in message
...
This is probably just a matter for careful selection of a circuit breaker.
Transformers have a volt-second limit (and that means 50 Hz at rated
voltage is more likely to saturate the core than 60 Hz at rated voltage).
The volt-second limit applies to the UNLOADED transformer, though,
so a blade-welding cycle (with a nice big load on the secondary
while current is flowing in the work) is likely to be trouble-free.
If the transformer is switched on before the blade parts are butted,
it could saturate and blow the main breaker (so putting a 20A breaker
local to the unit would be more convenient if it needs resetting).

Another saturation protection would be a good fast-blow fuse (because
if it isn't the breaker or fuse that blows, it's the copper in the
transformer).

On Thu, 11 Aug 2011 12:17:15 -0400, "Josepi"
wrote:

I would be sure our paths should have crossed. You sound younger than I
would have thought, perhaps.

Is your dad still alive? Not a roth in there?


-----------
wrote in message ...
My Dad was an electrician doing rural electrification in Waterloo
Region in the sixties.And residential wiring until his retirement 15
or so years ago
Dad's still alive. Almost lost him this spring, but doing reasonably
well right now. He's 82. I'm just shy of 60.
No Roth blood, but know a lot of Roths, and lived between Pool and
Milverton for a while as a kid. Whitney Farms ring a bell??
Or H&S Electic? Or AB Snyder Electric (Dad's older brother), Quality
Lighting, Gemor Electric, Aden Fry? Ron Hoy Electric, Gosen Electric?

On Thu, 11 Aug 2011 14:14:49 -0700 (PDT), whit3rd
wrote:

On Wednesday, August 10, 2011 9:15:19 PM UTC-4, Jon Anderson wrote:
On 8/10/2011 3:22 PM, David Lesher wrote:

Oh, an important exception or two. MANY power supplies for computers
and entertainment gadgets are "switchers".

Let me tell you, that's one HELL of a bang when a 110 PS gets socked
with 220!

Most modern computer supplies either have a switch, or autoswitch. I
haven't seen a '110 PS' in decades. Some, which use a manual switch,
have a hard-to-get-to fuse. The fuse can pop, loud.
Virtually every power supply I have around here is either
"universal" or 115/230. Never seen a 120/240 one, and the universals
are generally good from 100 to 240 - with the odd one being 90 to 250.

On Thu, 11 Aug 2011 19:27:17 +0000 (UTC), David Lesher
wrote:

Jon Anderson writes:

On 8/10/2011 6:06 PM, Michael A. Terrell wrote:

Sigh. That 'Toroid' is wound from steel tape. You can't make a
decent 50 or 60 Hz transformer without it.

sheepish grin Well, I've never cut one apart, so didn't know. Can't
SEE any steel... G


Some are ferrite iron power imbedded in the donut, but trust me,
it's got something magnetic....
Ferrite's no good for 60hz and any kind of power.

On 2011-08-11, David Lesher wrote:
Jon Anderson writes:

On 8/10/2011 6:06 PM, Michael A. Terrell wrote:

Sigh. That 'Toroid' is wound from steel tape. You can't make a
decent 50 or 60 Hz transformer without it.

sheepish grin Well, I've never cut one apart, so didn't know. Can't
SEE any steel... G


Some are ferrite iron power imbedded in the donut, but trust me,
it's got something magnetic....

And the ferrite iron is for high frequencies -- perhaps a DC-DC
switching mode converter, not for low frequencies like 60 Hz or 50 Hz.
Not even for aircraft 400 Hz.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

On Thu, 11 Aug 2011 20:47:41 -0400, "Josepi"
wrote:

Copper takes 100% overload for a long time. In power distribution systems
hours..it can glow read hot and still survive just fine.

Aluminum is a different beast.


And although the copper may survive, the insulation very well may not.
---------------

"whit3rd" wrote in message
...
This is probably just a matter for careful selection of a circuit breaker.
Transformers have a volt-second limit (and that means 50 Hz at rated
voltage is more likely to saturate the core than 60 Hz at rated voltage).
The volt-second limit applies to the UNLOADED transformer, though,
so a blade-welding cycle (with a nice big load on the secondary
while current is flowing in the work) is likely to be trouble-free.
If the transformer is switched on before the blade parts are butted,
it could saturate and blow the main breaker (so putting a 20A breaker
local to the unit would be more convenient if it needs resetting).

Another saturation protection would be a good fast-blow fuse (because
if it isn't the breaker or fuse that blows, it's the copper in the
transformer).

"DoN. Nichols" writes:

Some are ferrite iron power imbedded in the donut, but trust me,
it's got something magnetic....

And the ferrite iron is for high frequencies -- perhaps a DC-DC
switching mode converter, not for low frequencies like 60 Hz or 50 Hz.
Not even for aircraft 400 Hz.

Did not mean to imply it was; just pointing out that toroids use
magnetics just as old fashioned transformers do....they ain't
magic.
--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

"Jon Anderson" wrote in message
...
Ok, thought I'd spelled it out, but didn't. Here's the blade welder specs:

220 volts
20 amp
60 Hz
1 phase
Instantaneous KVA 4
Continuous KVA 5 or .5, the potential decimal point being high enough it's
not clearly a decimal point. But if instantaneous means inrush, then maybe
.5 KVA continuous makes sense.

Sounds like I'd best find a local electrician that can give me a
definitive answer.
Or weld up a life time supply of blades before I go...G

Jon



The usual distribution system in Australia is 3 phase 415 volt, 50 Hertz to
the street, but each customer gets a phase to neutral to their house.
Phase to neutral is in fact not 220 volts but is more like 230 or 240 volts.
The number of customers on each phase is managed to maintain a reasonably
even load on each phase. Until recently it was difficult to get 3 phase 415
volt power to a private dwelling, but the increase in large air conditioning
split systems has made it relatively easy to get 3 phase.

Yes this is very true. I guess bare overhead lines are a little different

1-------------------------
wrote in message ...
And although the copper may survive, the insulation very well may not.

2-------------------------
On Thu, 11 Aug 2011 20:47:41 -0400, "Josepi"
wrote:
Copper takes 100% overload for a long time. In power distribution systems
hours..it can glow read hot and still survive just fine.

Aluminum is a different beast.

239.6 volts in conjunction with the N.American world standard of 240v

1----------------------------
"Grumpy" wrote in message
. au...
The usual distribution system in Australia is 3 phase 415 volt, 50 Hertz to
the street, but each customer gets a phase to neutral to their house.
Phase to neutral is in fact not 220 volts but is more like 230 or 240 volts.
The number of customers on each phase is managed to maintain a reasonably
even load on each phase. Until recently it was difficult to get 3 phase 415
volt power to a private dwelling, but the increase in large air conditioning
split systems has made it relatively easy to get 3 phase.
2--------------------------
"Jon Anderson" wrote in message
...
Ok, thought I'd spelled it out, but didn't. Here's the blade welder specs:

220 volts
20 amp
60 Hz
1 phase
Instantaneous KVA 4
Continuous KVA 5 or .5, the potential decimal point being high enough it's
not clearly a decimal point. But if instantaneous means inrush, then maybe
.5 KVA continuous makes sense.

Sounds like I'd best find a local electrician that can give me a
definitive answer.
Or weld up a life time supply of blades before I go...G

Jon

Most of those are familiar. Snyder, Gosen, Gemor, Ron Hoy. I was in Kit.

Snyder joined up with Tschirhardt? now T&S Electric?. I hung out with
Cronin at work.

1----------------------------

Dad's still alive. Almost lost him this spring, but doing reasonably
well right now. He's 82. I'm just shy of 60.
No Roth blood, but know a lot of Roths, and lived between Pool and
Milverton for a while as a kid. Whitney Farms ring a bell??
Or H&S Electic? Or AB Snyder Electric (Dad's older brother), Quality
Lighting, Gemor Electric, Aden Fry? Ron Hoy Electric, Gosen Electric?

I always just assumed it was too expensive but was much better (less
losses). Any reasons for that known?

1-----------------
wrote in message ...
Ferrite's no good for 60hz and any kind of power.

On Fri, 12 Aug 2011 12:27:10 -0400, "Josepi"
wrote:

I always just assumed it was too expensive but was much better (less
losses). Any reasons for that known?

1-----------------
wrote in message ...
Ferrite's no good for 60hz and any kind of power.


The maximum working flux density of ferrite is only about 1/3 of
that for silicon iron. A ferrite 50/60Hz power transformer would
be more than 3 times bigger than the silicon iron equivalent

However the high frequency losses are much lower and at
frequencies higher than a few thousand Hz ferrite design are
smaller and more efficient.

High power designs are common in the frequency range a few
hundred KHz to a few MHz

Jim