From: Gerard Bok on
On Tue, 1 Jun 2010 14:12:36 +0100, "N_Cook" <diverse(a)tcp.co.uk>
wrote:

>Gerard Bok <bok118(a)zonnet.nl> wrote in message
>news:4c04ef34.3464695(a)News.Individual.NET...
>> On Tue, 1 Jun 2010 10:37:06 +0100, "N_Cook" <diverse(a)tcp.co.uk>
>> wrote:
>>
>> >About year 1999, USA make, for export
>> >In line , not 2 or more separate primary windings, DC ohms to nearest 0.1
>> >ohm. I'm assuming same gauge wire throughout
>> >Labelled by me as A,B,C,D,E crossplot (message souce maybe equispaced
>font)
>> >
>> >--- A B C D E
>> >A --- 9.2 8.5 12.5 1.5
>> >B 9.2 --- 0.6 3.6 7.6
>> >C 8.5 0.6 --- 4.2 7.6
>> >D 12.5 3.6 4.2 --- 11.1
>> >E 1.5 7.6 7.6 11.1 ---
>> >
>> >
>> >Would D-E / D-A be 220/240Vac or 230/250V ac?
>> >what would likely be the 110 or 130V interconnctions option ?
>> >Other than checking using a variac , any other tips ?
>>
>> Assuming the beast also has a secundary, --possably even marked
>> with a voltage-- I would apply that voltage (from another
>> transformer) and measure the voltages on the primary terminals.

>I hadn't actually thought of that but problem is which crosslink/s? for 110
>or 130 V operation.

Crosslinks ?
From your original message I read that all primary connections
connect to one continuous winding.

Transformers designed for minimal copper use contain 2 identical
sets of windings. Those get connected in parallel for use on 115
volt and in series for 230 Volt.

As long as there is DC continuity I wouldn't attempt any cross
wiring ;-)

--
Kind regards,
Gerard Bok
From: Phil Allison on

<PlainBill47(a)yahoo.com>

>
> But a better way to look at is is the increments
>
> A-E = winding a = 1.5
> E-C = winding b = 7.0
> C-B = winding c = 0.7
> B-D = winding d = 3.3


** OK - let's assume two gauges of wire ARE being used and the 3.3 ohm
tapping B-D is 100V for Japan.

Then by ratio of resistance, the 0.7 ohm tapping C-B is 20 volts making C-D
120 volts for the USA etc.

Similarly, E-C is another 100 volt tapping ( using thinner wire) making E-D
220 volts for Europe.

Again, A-E is another 20 volt tapping making the whole winding 240 volts.


..... Phil




From: N_Cook on
Gerard Bok <bok118(a)zonnet.nl> wrote in message
news:4c054944.6350870(a)News.Individual.NET...
> On Tue, 1 Jun 2010 14:12:36 +0100, "N_Cook" <diverse(a)tcp.co.uk>
> wrote:
>
> >Gerard Bok <bok118(a)zonnet.nl> wrote in message
> >news:4c04ef34.3464695(a)News.Individual.NET...
> >> On Tue, 1 Jun 2010 10:37:06 +0100, "N_Cook" <diverse(a)tcp.co.uk>
> >> wrote:
> >>
> >> >About year 1999, USA make, for export
> >> >In line , not 2 or more separate primary windings, DC ohms to nearest
0.1
> >> >ohm. I'm assuming same gauge wire throughout
> >> >Labelled by me as A,B,C,D,E crossplot (message souce maybe equispaced
> >font)
> >> >
> >> >--- A B C D E
> >> >A --- 9.2 8.5 12.5 1.5
> >> >B 9.2 --- 0.6 3.6 7.6
> >> >C 8.5 0.6 --- 4.2 7.6
> >> >D 12.5 3.6 4.2 --- 11.1
> >> >E 1.5 7.6 7.6 11.1 ---
> >> >
> >> >
> >> >Would D-E / D-A be 220/240Vac or 230/250V ac?
> >> >what would likely be the 110 or 130V interconnctions option ?
> >> >Other than checking using a variac , any other tips ?
> >>
> >> Assuming the beast also has a secundary, --possably even marked
> >> with a voltage-- I would apply that voltage (from another
> >> transformer) and measure the voltages on the primary terminals.
>
> >I hadn't actually thought of that but problem is which crosslink/s? for
110
> >or 130 V operation.
>
> Crosslinks ?
> From your original message I read that all primary connections
> connect to one continuous winding.
>
> Transformers designed for minimal copper use contain 2 identical
> sets of windings. Those get connected in parallel for use on 115
> volt and in series for 230 Volt.
>
> As long as there is DC continuity I wouldn't attempt any cross
> wiring ;-)
>
> --
> Kind regards,
> Gerard Bok

This is what was confusing me , I don't often come across USA transformers ,
they must have plenty of copper to waste and unnecessarily larger
transformers. Only ever seem to see 2 separate primaries in the UK , in the
main, maybe some 10 or 20 V taps in addition.
For this continuous one and generally for this sort of mains transformer.
The"240V" ends cannot be returned to form one 110V connection and a mid
point the other 110V connection for that option, as counter winding sense
for the two "halves" and so no secondary volts.
So part of the winding wasted and the 110V
section of primary perhaps a larger gauge. I suppose measuring inductance
may have helped




From: PeterD on
On Wed, 2 Jun 2010 08:46:56 +0100, "N_Cook" <diverse(a)tcp.co.uk> wrote:

>Gerard Bok <bok118(a)zonnet.nl> wrote in message
>news:4c054944.6350870(a)News.Individual.NET...
>> On Tue, 1 Jun 2010 14:12:36 +0100, "N_Cook" <diverse(a)tcp.co.uk>
>> wrote:
>>
>> >Gerard Bok <bok118(a)zonnet.nl> wrote in message
>> >news:4c04ef34.3464695(a)News.Individual.NET...
>> >> On Tue, 1 Jun 2010 10:37:06 +0100, "N_Cook" <diverse(a)tcp.co.uk>
>> >> wrote:
>> >>
>> >> >About year 1999, USA make, for export
>> >> >In line , not 2 or more separate primary windings, DC ohms to nearest
>0.1
>> >> >ohm. I'm assuming same gauge wire throughout
>> >> >Labelled by me as A,B,C,D,E crossplot (message souce maybe equispaced
>> >font)
>> >> >
>> >> >--- A B C D E
>> >> >A --- 9.2 8.5 12.5 1.5
>> >> >B 9.2 --- 0.6 3.6 7.6
>> >> >C 8.5 0.6 --- 4.2 7.6
>> >> >D 12.5 3.6 4.2 --- 11.1
>> >> >E 1.5 7.6 7.6 11.1 ---
>> >> >
>> >> >
>> >> >Would D-E / D-A be 220/240Vac or 230/250V ac?
>> >> >what would likely be the 110 or 130V interconnctions option ?
>> >> >Other than checking using a variac , any other tips ?
>> >>
>> >> Assuming the beast also has a secundary, --possably even marked
>> >> with a voltage-- I would apply that voltage (from another
>> >> transformer) and measure the voltages on the primary terminals.
>>
>> >I hadn't actually thought of that but problem is which crosslink/s? for
>110
>> >or 130 V operation.
>>
>> Crosslinks ?
>> From your original message I read that all primary connections
>> connect to one continuous winding.
>>
>> Transformers designed for minimal copper use contain 2 identical
>> sets of windings. Those get connected in parallel for use on 115
>> volt and in series for 230 Volt.
>>
>> As long as there is DC continuity I wouldn't attempt any cross
>> wiring ;-)
>>
>> --
>> Kind regards,
>> Gerard Bok
>
>This is what was confusing me , I don't often come across USA transformers ,

If it is truely a USA only transformer, it will not have a winding
higher than 120 volts! USA makers were not export oriented, and the
few export units were typically fitted with different transformers,
but the run-of-the-mill domestic production was made with a 120 volt
primary (only). Export models were typically setup for 100/120/240
volts. (Japan, USA & and other countries with an approximate 120 volt
standard, and other countries with an approximate 240 volt standard.)

>they must have plenty of copper to waste and unnecessarily larger
>transformers.

Makers were (and still are) incredibly cheap, and will resort to all
kninds of tricks to save a penny. I don't see many (if any) who will
waste money on copper that will (in their opinion) never be used.

>Only ever seem to see 2 separate primaries in the UK , in the
>main, maybe some 10 or 20 V taps in addition.
>For this continuous one and generally for this sort of mains transformer.
>The"240V" ends cannot be returned to form one 110V connection and a mid
>point the other 110V connection for that option, as counter winding sense
>for the two "halves" and so no secondary volts.
>So part of the winding wasted and the 110V
>section of primary perhaps a larger gauge. I suppose measuring inductance
>may have helped
>

About the best thing would be to measure the primary volts while
powering the secondary with its rated voltage. However, I suspect you
don't know the secondary specifications either, so that is difficult.

I'd probably look at the secondary and give it a known, low voltage
(say 6 v AC) and measure the ratio of the primary voltages. That would
be better than static DC resistance measurements which can easily be
affected by inductance and wire gauge.


From: PeterD on
On Wed, 2 Jun 2010 15:57:16 +1000, "Phil Allison" <phil_a(a)tpg.com.au>
wrote:

>
><PlainBill47(a)yahoo.com>
>
>>
>> But a better way to look at is is the increments
>>
>> A-E = winding a = 1.5
>> E-C = winding b = 7.0
>> C-B = winding c = 0.7
>> B-D = winding d = 3.3
>
>
>** OK - let's assume two gauges of wire ARE being used and the 3.3 ohm
>tapping B-D is 100V for Japan.
>
>Then by ratio of resistance, the 0.7 ohm tapping C-B is 20 volts making C-D
>120 volts for the USA etc.
>
>Similarly, E-C is another 100 volt tapping ( using thinner wire) making E-D
>220 volts for Europe.
>
>Again, A-E is another 20 volt tapping making the whole winding 240 volts.
>
>
>.... Phil
>
>
>

Which makes sense!