Imagine you are asked to install a used buck-boost transformer. Imagine you
could normally do this in a few minutes. Except if the leads were cut short
such that identifying characters on the leads' insulation were missing.
Identifying 2 leads belonging to any one winding is straightforward ohm meter
work. Maybe use of a ESR meter might help separate the X windings from the H
windings?. But identifying which specific winding is which and which end is
whichnot so straightforward. For me.
How would you go about identifying the windings? Maybe use a Variac to input
voltage to each of the windings then measure the output of the others? What
outputs should I expect at, for example, the H3/H4 winding with a voltage on
H1/H2 winding? How to identify backward connection of a winding?
Are the two H windings identical? The two X windings?
Suggestions welcome.
This is a 208 -> 230 (ie, 12 & 24 v buck-boost voltage) single-phase
autotransformer in N. America.
Thanks.
On 2/11/2014 1:40 PM, DaveC wrote:
> Imagine you are asked to install a used buck-boost transformer. Imagine you
> could normally do this in a few minutes. Except if the leads were cut short
> such that identifying characters on the leads' insulation were missing.
>
> Identifying 2 leads belonging to any one winding is straightforward ohm meter
> work. Maybe use of a ESR meter might help separate the X windings from the H
> windings?. But identifying which specific winding is which and which end is
> whichnot so straightforward. For me.
>
> How would you go about identifying the windings? Maybe use a Variac to input
> voltage to each of the windings then measure the output of the others? What
> outputs should I expect at, for example, the H3/H4 winding with a voltage on
> H1/H2 winding? How to identify backward connection of a winding?
>
> Are the two H windings identical? The two X windings?
>
> Suggestions welcome.
>
> This is a 208 -> 230 (ie, 12 & 24 v buck-boost voltage) single-phase
> autotransformer in N. America.
>
> Thanks.
>
Hey dave.. Imagine only sending this to groups that would be
interested. Woodworking , probably not
-=-=-=-
Leon,
Frequently wood- and metal-working groups are interested in mains wiring for
their equipment. They're not completely disinterested in my experience...
Dropped.
Dave
On Tue, 11 Feb 2014 13:07:35 -0800, Joerg <[email protected]>
wrote:
>
>Oops, if yours is not an "electronic transformer" disregard the above.
>But then it's not really buck/boost.
Buck-boost in this context refers to an electrical transformer that
has the primary attached across the mains, and the secondary either
boosts or bucks the mains voltage depending on whether it's connected
in phase or out of phase. It has an advantage over (say) a 240:208
tranformer in that the core size can be much smaller.
--sp
In article
<[email protected]>,
DaveC <[email protected]> wrote:
> Imagine you are asked to install a used buck-boost transformer. Imagine you
> could normally do this in a few minutes. Except if the leads were cut short
> such that identifying characters on the leads' insulation were missing.
>
> Identifying 2 leads belonging to any one winding is straightforward ohm meter
> work. Maybe use of a ESR meter might help separate the X windings from the H
> windings?. But identifying which specific winding is which and which end is
> which--not so straightforward. For me.
>
> How would you go about identifying the windings? Maybe use a Variac to input
> voltage to each of the windings then measure the output of the others? What
> outputs should I expect at, for example, the H3/H4 winding with a voltage on
> H1/H2 winding? How to identify backward connection of a winding?
>
> Are the two H windings identical? The two X windings?
>
> Suggestions welcome.
>
> This is a 208 -> 230 (ie, 12 & 24 v buck-boost voltage) single-phase
> autotransformer in N. America.
>
> Thanks.
I am intrigued by this post and the replies. The post has little useful
information and the replies are based on assumption that that may have
little connection to reality. From the description, I have no idea if
there really is an auto transformer, completely separate windings, or a
combination of both. Also I have no idea what a description "H3/H4
winding" means. I refuse to guess. Try to understand this communication
is in writing and not telepathic.
1. An ohmmeter can separate one set of connected windings from other
such sets. If there are taps, you might even find the ends of the
windings and and the order of the taps.
2. Put all these winding sets in series.
3. Using your Variac, energize one winding (without saturating).
4. From voltage measurements you should be able to find the turn ratios
amongst the various windings.
5. You should also be able to locate which ends of a winding are in
phase or out of phase with the ends of your excited winding.
In the future, realize that good communication requires good grammar and
little ambiguity.
--
Sam
Conservatives are against Darwinism but for natural selection.
Liberals are for Darwinism but totally against any selection.
DaveC wrote:
> Imagine you are asked to install a used buck-boost transformer. Imagine you
> could normally do this in a few minutes. Except if the leads were cut short
> such that identifying characters on the leads' insulation were missing.
>
> Identifying 2 leads belonging to any one winding is straightforward ohm meter
> work. Maybe use of a ESR meter might help separate the X windings from the H
> windings?. But identifying which specific winding is which and which end is
> whichnot so straightforward. For me.
>
> How would you go about identifying the windings? Maybe use a Variac to input
> voltage to each of the windings then measure the output of the others? What
> outputs should I expect at, for example, the H3/H4 winding with a voltage on
> H1/H2 winding? How to identify backward connection of a winding?
>
> Are the two H windings identical? The two X windings?
>
> Suggestions welcome.
>
> This is a 208 -> 230 (ie, 12 & 24 v buck-boost voltage) single-phase
> autotransformer in N. America.
>
> Thanks.
>
Assuming you have ohmed them all out and thus know how many windings
there are and how many taps each has:
Hook a function generator to one winding (any winding), best one that
has no taps. Measure the amplitude you get at a 10kHz or so. Most
multimeters will do that, or a scope. Now measure the amplitude at all
others. That gives you roughly the turns ratios.
Now you normally also need to know which one is the helper winding
because that sits close to the primary in the stack and should under no
circumstance be mixed up with any of the scondaries. From your previous
measurement you know which one is the primary (on 120VAC to low DC
supplies that's the one with the highest number of turns). Hook that to
one side of the capacitance terminal on your multimeter. Keep leads as
short as possible. Measure capacitance to all others. Usually the
highest capacitance indicates which windings are closest to each other.
--
Regards, Joerg
http://www.analogconsultants.com/
Joerg wrote:
> DaveC wrote:
>> Imagine you are asked to install a used buck-boost transformer. Imagine you
>> could normally do this in a few minutes. Except if the leads were cut short
>> such that identifying characters on the leads' insulation were missing.
>>
>> Identifying 2 leads belonging to any one winding is straightforward ohm meter
>> work. Maybe use of a ESR meter might help separate the X windings from the H
>> windings?. But identifying which specific winding is which and which end is
>> whichnot so straightforward. For me.
>>
>> How would you go about identifying the windings? Maybe use a Variac to input
>> voltage to each of the windings then measure the output of the others? What
>> outputs should I expect at, for example, the H3/H4 winding with a voltage on
>> H1/H2 winding? How to identify backward connection of a winding?
>>
>> Are the two H windings identical? The two X windings?
>>
>> Suggestions welcome.
>>
>> This is a 208 -> 230 (ie, 12 & 24 v buck-boost voltage) single-phase
>> autotransformer in N. America.
>>
>> Thanks.
>>
>
> Assuming you have ohmed them all out and thus know how many windings
> there are and how many taps each has:
>
> Hook a function generator to one winding (any winding), best one that
> has no taps. Measure the amplitude you get at a 10kHz or so. Most
> multimeters will do that, or a scope. Now measure the amplitude at all
> others. That gives you roughly the turns ratios.
>
> Now you normally also need to know which one is the helper winding
> because that sits close to the primary in the stack and should under no
> circumstance be mixed up with any of the scondaries. From your previous
> measurement you know which one is the primary (on 120VAC to low DC
> supplies that's the one with the highest number of turns). Hook that to
> one side of the capacitance terminal on your multimeter. Keep leads as
> short as possible. Measure capacitance to all others. Usually the
> highest capacitance indicates which windings are closest to each other.
>
Oops, if yours is not an "electronic transformer" disregard the above.
But then it's not really buck/boost.
--
Regards, Joerg
http://www.analogconsultants.com/
Spehro Pefhany wrote:
> On Tue, 11 Feb 2014 13:07:35 -0800, Joerg <[email protected]>
> wrote:
>
>> Oops, if yours is not an "electronic transformer" disregard the above.
>> But then it's not really buck/boost.
>
> Buck-boost in this context refers to an electrical transformer that
> has the primary attached across the mains, and the secondary either
> boosts or bucks the mains voltage depending on whether it's connected
> in phase or out of phase. It has an advantage over (say) a 240:208
> tranformer in that the core size can be much smaller.
>
Thanks, never heard that. But that'll be easy, the primary has thin wire
and the secondary thick. One could just hook up the primary (even if
just to 120VAC for a test) and then connect up the others to see in
which direction it'll push the voltage.
--
Regards, Joerg
http://www.analogconsultants.com/
On 11/02/2014 11:40 AM, DaveC wrote:
> Imagine you are asked to install a used buck-boost transformer. Imagine you
> could normally do this in a few minutes. Except if the leads were cut short
> such that identifying characters on the leads' insulation were missing.
>
> Identifying 2 leads belonging to any one winding is straightforward ohm meter
> work. Maybe use of a ESR meter might help separate the X windings from the H
> windings?. But identifying which specific winding is which and which end is
> whichnot so straightforward. For me.
>
> How would you go about identifying the windings? Maybe use a Variac to input
> voltage to each of the windings then measure the output of the others? What
> outputs should I expect at, for example, the H3/H4 winding with a voltage on
> H1/H2 winding? How to identify backward connection of a winding?
>
> Are the two H windings identical? The two X windings?
>
> Suggestions welcome.
>
> This is a 208 -> 230 (ie, 12 & 24 v buck-boost voltage) single-phase
> autotransformer in N. America.
>
> Thanks.
>
-----------
It appears that you have 4 windings- 2 heavy and 2 lighter ones. For a
simple buck or boost transformer V +/dv you only need two windings so it
appears that the transformer can be used for 120V input or 240V input as
can the transformer whose diagram you sent.
The HV input winding(s) will have thinner conductors.
You can get a reasonable approximation of turns rations by measuring
resistances -roughly proportional to ths square of the turns.You have 4
coils H1-H2 H3-H4 L1-L2 and L3-l4
Take one of the HV coils- label it H1-H2 and energize it at a low
voltage to start (always err on the low side) with H1 at the neutral
end. Measure the voltage across all coils This will establish turns
ratios. Don't label numerically but simply with regard to voltage
The other thing is to establish polarity.
Now take one of the other coils and connect one end of it to the H2 or
high terminal of the first coil (please de-energize while doing this).
Measure the total voltage from neutral to the free end- if it is more
than the H1-H2 applied voltage- it is boosting so free end can be lab
with an even number H4, L2 or L4 and give the other end the
corresponding odd number. If the voltage is less, it is bucking so give
it an odd number. Do this with each of the other coils -so you will
end up with another measure of turns ratio but, more importantly, you
will have their polarity established with even numbers as the same
polarity and the coils all numbered. Using this scheme, your diagram
would be in a buck mode.
Now you can figure out the combinations available to you.
there are quite a few.
--
Don Kelly
remove the cross to reply
On Tue, 11 Feb 2014 11:40:43 -0800, DaveC <[email protected]> wrote:
>Imagine you are asked to install a used buck-boost transformer. Imagine you
>could normally do this in a few minutes. Except if the leads were cut short
>such that identifying characters on the leads' insulation were missing.
>
>Identifying 2 leads belonging to any one winding is straightforward ohm meter
>work. Maybe use of a ESR meter might help separate the X windings from the H
>windings?. But identifying which specific winding is which and which end is
>whichnot so straightforward. For me.
>
>How would you go about identifying the windings? Maybe use a Variac to input
>voltage to each of the windings then measure the output of the others? What
>outputs should I expect at, for example, the H3/H4 winding with a voltage on
>H1/H2 winding? How to identify backward connection of a winding?
>
>Are the two H windings identical? The two X windings?
>
>Suggestions welcome.
>
>This is a 208 -> 230 (ie, 12 & 24 v buck-boost voltage) single-phase
>autotransformer in N. America.
>
>Thanks.
Well, you'd expect the 12/24V windings to be MUCH lower resistance
than the primary. If the 12/24 is a center-tapped winding, the 0..12
may be lower resistance (wound from fatter wire) than the 12:24
winding.
You could fire it up with a light bulb in series and measure the
voltages.
"DaveC" wrote in message
news:[email protected]...
> How would you go about identifying the windings? Maybe use
> a Variac to input voltage to each of the windings then measure
> the output of the others?
Why not try it and see? Then we'll be able to study the data and give you some
advice.
On a sunny day (Tue, 11 Feb 2014 12:19:15 -0800) it happened "William
Sommerwerck" <[email protected]> wrote in
<[email protected]>:
>"DaveC" wrote in message
>news:[email protected]...
>
>> How would you go about identifying the windings? Maybe use
>> a Variac to input voltage to each of the windings then measure
>> the output of the others?
>
>Why not try it and see? Then we'll be able to study the data and give you some
>advice.
I have put transformers on the soundcard output with sgen signal generator (Linux).
If you have a decent audio power amp you can even run stuff from it.
I did run my cryocooler at 60.5 Hz (specified) that way from the soundcard
with a 230 to 40V transfomer in reverse, 100W or so.
Volume control!! A real potmeter on the amp!
Should have taken a picture...
Now it is back on original transistor PWM unit.
"DaveC" <[email protected]> wrote in message
news:[email protected]...
> Imagine you are asked to install a used buck-boost transformer.
> Imagine you
> could normally do this in a few minutes. Except if the leads were
> cut short
> such that identifying characters on the leads' insulation were
> missing.
>
> Identifying 2 leads belonging to any one winding is straightforward
> ohm meter
> work. Maybe use of a ESR meter might help separate the X windings
> from the H
> windings?. But identifying which specific winding is which and which
> end is
> whichnot so straightforward. For me.
>
> How would you go about identifying the windings? Maybe use a Variac
> to input
> voltage to each of the windings then measure the output of the
> others? What
> outputs should I expect at, for example, the H3/H4 winding with a
> voltage on
> H1/H2 winding? How to identify backward connection of a winding?
>
> Are the two H windings identical? The two X windings?
>
> Suggestions welcome.
>
> This is a 208 -> 230 (ie, 12 & 24 v buck-boost voltage) single-phase
> autotransformer in N. America.
>
> Thanks.
>
http://ecmweb.com/content/basics-transformers-part-5
On Tue, 11 Feb 2014 11:40:43 -0800, DaveC <[email protected]> wrote:
>Imagine you are asked to install a used buck-boost transformer. Imagine you
>could normally do this in a few minutes. Except if the leads were cut short
>such that identifying characters on the leads' insulation were missing.
>
>Identifying 2 leads belonging to any one winding is straightforward ohm meter
>work. Maybe use of a ESR meter might help separate the X windings from the H
>windings?. But identifying which specific winding is which and which end is
>whichnot so straightforward. For me.
>
>How would you go about identifying the windings? Maybe use a Variac to input
>voltage to each of the windings then measure the output of the others? What
>outputs should I expect at, for example, the H3/H4 winding with a voltage on
>H1/H2 winding? How to identify backward connection of a winding?
>
>Are the two H windings identical? The two X windings?
>
>Suggestions welcome.
>
>This is a 208 -> 230 (ie, 12 & 24 v buck-boost voltage) single-phase
>autotransformer in N. America.
>
>Thanks.
I have the wiring diagrams in .pdf for Square D buck/boost xmfrs. The
X wires are the heavy wires and the H wires the thin wires. X1 and X2
are the ends of one winding. X2 and X3 the ends of another winding.
The other windings are similar. Anyway, if you send me an email I'll
send you the .pdf of the wiring manual. Then you will be able to
figure out how to wire the thing. It should be easy enough, just
measure the output in one random configuration and you will be able to
tell what's what by looking at the manual.
Eric
---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com
You certainly have this rather heavily cross-posted. I'm following up
in rec.crafts.metalworking, and I'm assuming that you are planning to
run a machine tool from this. You may get vastly different replies from
the different newsgroups -- or just plain ignored. (Probably the
sci.electronics.design and sci.electronics.equipment newsgroups, as this
seems a bit off topic for them, just based on the newsgroup name.) If I
had any idea where you were reading it, I would restrict followups to
rec.crafts.metalworking where I am.
On 2014-02-11, DaveC <[email protected]> wrote:
> Imagine you are asked to install a used buck-boost transformer. Imagine you
> could normally do this in a few minutes. Except if the leads were cut short
> such that identifying characters on the leads' insulation were missing.
O.K. Any color coding of the leads, or are they all black (tar
in braided covering)?
> Identifying 2 leads belonging to any one winding is straightforward ohm meter
> work. Maybe use of a ESR meter might help separate the X windings from the H
> windings?. But identifying which specific winding is which and which end is
> whichnot so straightforward. For me.
Plain resistance measurements should be sufficient. I'm not
familiar with the X and H designations, and certainly not two of each
(unless it is designed for operation at two main voltages, like 120V or
240V -- or perhaps 240V or 480V. Isn't an ESR meter intended for
measuring the resistance in a capacitor, not a transformer?
> How would you go about identifying the windings? Maybe use a Variac to input
> voltage to each of the windings then measure the output of the others? What
> outputs should I expect at, for example, the H3/H4 winding with a voltage on
> H1/H2 winding? How to identify backward connection of a winding?
>
> Are the two H windings identical? The two X windings?
Assuming that it is for dual input voltages such as I suggested
above -- the two input windings would be the same resistance, and would
be connected in parallel for the lower voltage or in series for the
higher voltage.
> Suggestions welcome.
>
> This is a 208 -> 230 (ie, 12 & 24 v buck-boost voltage) single-phase
> autotransformer in N. America.
For the transformation shown, you should only need two windings
total -- again unless it is also intended for operation at an input
voltage twice or half the 230/208 nominal range. Three windings to get
your choice of 12V or 24V buck or boost.
Anyway -- for two total windings, I would expect one to have
significantly higher resistance than the other (and for two of each
winding, two would have significantly higher resistance than the other
two. Since the input and output are expected to handle about the same
current, they should be wound with the same wire gauge, and thus the
resistances would be about proportional to the voltages on each winding.
Given two -- pick one of the higher resistance windings and
connect it to the line (or through a Variac autotransformer set to half
voltage if the transformer is for both 120 and 240 range inputs.
Connect one end of the other higher resistance winding to one of the two
ends being connected to the line. Take an AC voltmeter, and connect
between the free lead and the remaining line input lead. If the voltage
measures about twice the line voltage, swap the free lead and the other
from that winding, and re-measure. You should measure something close to
zero (probably no more than a volt or two). Now -- mark the two which
are connected together as "S" (start), and the free end and the one
connected just to the other line input as "F" (finish). For the lower
voltage input range -- connect both "S" ends together to one side of the
line, and both "F" ends together to the other side of the line. For the
higher (say 230 VAC if it is a 230/460 volt transformer) you connect one
'S' to the 'F' of the other widing, and use the other two free ends (one
'S' and one 'F') to the line input.
If you want to determine whether the dual voltage is 115/230 or
230/460 Volts, take one of the input (higher resistance) windings, and
connect it to the 230 V with a 100 Watt 120 VAC light bulb in series.
If it lights brightly then 230 VAC is too much for one winding (it is
saturating the core) and you need the two in series.
Now -- that the input wires are sorted out, we move to the
output wires. Connect one end of each output winding to the other
output winding -- and measure the voltage both between the joined pair
of wires and each end -- they should give you your 12V AC. And if you
then measure between the two free ends and get 24VAC, swap ends on one
winding and check again for a very low voltage. At this point, you have
connected together either a 'S' for each of the secondary windings, or a
'F' for each. To determine which, connect the joined point to the side
of the input power connected to the wires marked 'F' (along with having
your input power going to the primary windings as determined above).
Now -- measure the voltage first between the two primary windings, and
then from the end to which your secondary windings is *not* connected,
to a free wend of the secondary winding. If the voltage measured is
lower than your input voltage, then mark the two joined secondary ends
as 'F', while if the voltage is higher, then mark the joined secondary
ends as 'S'. (Of course, mark each as to which winding it is connected
to. Being unfamiliar with the 'X' and 'H' designations, I would
personally mark them as "P1S", "P1F" "S1S" and S1F" (first of those is
"Primary 1 Start)", and similarly for S2 and P2.
Now -- to *use*, when you want to reduce the voltage (buck),
connect your input power to the primary start and finish wires (either
in parallel for the lower voltage range, or in series for the higher
voltage range), and connect the 'F' wires from the secondary to the 'F'
wires from the primary, so you will subtract 12 V from the 230 V or 24
V from the 460 V) and connect the load to the 'S' wires of the
secondary.
If you want to boost instead of buck, connect the 'S' of the
secondary to the 'F' of the primary, and the 'F' of the secondary to the
load.
If you want to buck or boost by 24V instead, use the two
secondary windings in series (one 'F' to the other winding's 'S', and
threat the free wires as the overall 'S' and 'F' wires. Hopefully, the
secondary wires will handle the series operation while the primary is in
parallel connection.
Be Careful and
Good Luck,
DoN.
--
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