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Identifying buck-boost transformer windings?
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DaveC
Feb 11, 2014, 2:40:43 PM2/11/14
to
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.
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.
DaveC
Feb 11, 2014, 2:47:53 PM2/11/14
to
The tech support people at a couple of transformer manufacturers couldn't
help.
Dave
help.
Dave
William Sommerwerck
Feb 11, 2014, 3:19:15 PM2/11/14
to
"DaveC" wrote in message
news:0001HW.CF1FBCBB...@news.eternal-september.org...
> 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.
news:0001HW.CF1FBCBB...@news.eternal-september.org...
> 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?
advice.
Jon Elson
Feb 11, 2014, 3:20:54 PM2/11/14
to
DaveC wrote:
> 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?
Yup, put a small voltage on one winding, and see if you get a much
> 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?
larger voltage on another. If so, you can tell which is the H and
which is the low voltage one. Once you have identified the high and
low voltage windings, you can put them in series to determine
which way the phasing goes. If you get, say 50 V out of each of
two windings, and then put them in series and get zero, you have them
phased backwards. Reverse one winding, and you should get 100 V.
Jon
Jan Panteltje
Feb 11, 2014, 3:29:03 PM2/11/14
to
On a sunny day (Tue, 11 Feb 2014 12:19:15 -0800) it happened "William
Sommerwerck" <grizzle...@comcast.net> wrote in
<lde0k6$l3d$1...@dont-email.me>:
I have put transformers on the soundcard output with sgen signal generator (Linux).
If you have a decent audio power amp you can even run stuff from it.
I did run my cryocooler at 60.5 Hz (specified) that way from the soundcard
with a 230 to 40V transfomer in reverse, 100W or so.
Volume control!! A real potmeter on the amp!
Should have taken a picture...
Now it is back on original transistor PWM unit.
Sommerwerck" <grizzle...@comcast.net> wrote in
<lde0k6$l3d$1...@dont-email.me>:
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.
et...@whidbey.com
Feb 11, 2014, 3:30:42 PM2/11/14
to
On Tue, 11 Feb 2014 11:40:43 -0800, DaveC <inv...@invalid.net> 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限not so straightforward. For me.
>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
>
>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
>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.
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
jurb...@gmail.com
Feb 11, 2014, 3:34:14 PM2/11/14
to
I would generate a non-symmetrical waveform like maybe a sawtooth and apply it. You can determine the phase easily (that might be important lol) as well as something of the turns ratio.
After that switch to a square wave to get the turns ratio more accurately. Rock the frequency to where it is the most efficient (puts out the most). Some transformers will respond well enough with the sawtooth, but the square wave is alot easier to measure. Also, if you need to determine the current capability of each winding, that is also easier to do with a square wave.
You can determine this all without a scope, but a scope makes it all alot easier using the sawtooth. With the square wave you would have to try to boost and buck each winding to see which way is "up".
I would suggest checking the current capability of each secondary if the voltages are close because alot of times there is not a tapped secondary, there are two secondaries that are connected together externaly.
All worst case scenario of course. If the thing only has five wires or something it is a piece of cake. Too easy to even ask about.
After that switch to a square wave to get the turns ratio more accurately. Rock the frequency to where it is the most efficient (puts out the most). Some transformers will respond well enough with the sawtooth, but the square wave is alot easier to measure. Also, if you need to determine the current capability of each winding, that is also easier to do with a square wave.
You can determine this all without a scope, but a scope makes it all alot easier using the sawtooth. With the square wave you would have to try to boost and buck each winding to see which way is "up".
I would suggest checking the current capability of each secondary if the voltages are close because alot of times there is not a tapped secondary, there are two secondaries that are connected together externaly.
All worst case scenario of course. If the thing only has five wires or something it is a piece of cake. Too easy to even ask about.
Joerg
Feb 11, 2014, 4:05:12 PM2/11/14
to
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
Feb 11, 2014, 4:07:35 PM2/11/14
to
But then it's not really buck/boost.
Spehro Pefhany
Feb 11, 2014, 4:21:23 PM2/11/14
to
>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限not so straightforward. For me.
>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
>
>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
>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.
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.
Leon
Feb 11, 2014, 4:14:00 PM2/11/14
to
interested. Woodworking , probably not
Spehro Pefhany
Feb 11, 2014, 4:36:48 PM2/11/14
to
On Tue, 11 Feb 2014 13:07:35 -0800, Joerg <inv...@invalid.invalid>
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
wrote:
>
>Oops, if yours is not an "electronic transformer" disregard the above.
>But then it's not really buck/boost.
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
Joerg
Feb 11, 2014, 4:34:41 PM2/11/14
to
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.
DaveC
Feb 11, 2014, 5:44:18 PM2/11/14
to
> 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
Have a wiring diag:
> 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
http://oi59.tinypic.com/v3fuog.jpg
How to wire it isn't the question. Which wires are H1, H2, X1, X2, etc. is
the question.
Series light bulb or Variac (will use 120 mains for testing as that is the
only Variac I have...) seems the answer.
Remaining question: are H1/2 and H3/4 primary windings interchangeable? X1/2
and X3/4 windings interchangeable?
Thanks.
Salmon Egg
Feb 11, 2014, 6:26:39 PM2/11/14
to
In article
<0001HW.CF1FBCBB...@news.eternal-september.org>,
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.
<0001HW.CF1FBCBB...@news.eternal-september.org>,
DaveC <inv...@invalid.net> 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.
> 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
>
> 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
> 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.
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.
Jim Wilkins
Feb 11, 2014, 6:37:48 PM2/11/14
to
"DaveC" <inv...@invalid.net> wrote in message
news:0001HW.CF1FBCBB...@news.eternal-september.org...
news:0001HW.CF1FBCBB...@news.eternal-september.org...
> 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限not so straightforward. For me.
> 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
>
> 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
> 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.
>
Don Kelly
Feb 11, 2014, 7:10:52 PM2/11/14
to
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
Spehro Pefhany
Feb 11, 2014, 9:04:14 PM2/11/14
to
wire and any of the remaining 7 wires, what do you get? There are 28
unique combinations (8 * 7/2):
Eg.
Wire to Wire R (Ohms) ??
A B
A C
A D
A E
A F
A G
A H
B C
B D
B E
B F
B G
B H
C D
C E
C F
C G
C H
D E
D F
D G
D H
E F
E G
E H
F G
F H
G H
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
sp...@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
DoN. Nichols
Feb 12, 2014, 1:01:08 AM2/12/14
to
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 <inv...@invalid.net> 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
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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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 <inv...@invalid.net> 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.
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
> which限not 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?
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.
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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Email: <BPdnic...@d-and-d.com> | (KV4PH) Voice (all times): (703) 938-4564
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--- Black Holes are where God is dividing by zero ---
et...@whidbey.com
Feb 12, 2014, 12:15:12 PM2/12/14
to
In my first post I mentioned which wire were which. To reiterate, on
my xmfr, the heavy wires are the X wires, the thin wires are the H
wires. The difference in size is about 4 to 1. Now, these wires are
the ones that show coming out of the potting compound. I cannot see
the actual coils because the whole xmfr is potted. I looked at the
picture in the link you sent me. If this is all the info you have then
you don't have enough. I checked my email and I didn't see one from
you. The email address with my posts is a real one. Send me an email
and I'll send you the manual which will explain the whole thing. The
manual has many wiring diagrams which will help you get it right the
first time. Or just search online for a buck/boost wiring manual.
That's how I found mine. I'm no electrician or electronics guy and it
took me less than 15 minutes to figure out the wiring of the xmfrs for
my 3 phase machine.
Michael A. Terrell
Feb 13, 2014, 8:05:53 AM2/13/14
to
high voltage lead, and that 'H' is a low voltage lead.
If you'd ever installed one you would know that they have two
primaries and two secondaries, all four isolated. For 120, you parallel
the primaries in phase. The secondaries are connected in series with the
load. The phase affects the addition to or subtraction from the line
voltage. It isn't rocket science. I recently installed one on a pipe
bender at a factory, right after the company had moved to a larger
building.
That machine had two problems. It was built for 240 volts, and they
had 208. The other problem was that the so called industrial electrician
they hired wired it for 120 V because he was too damned lazy to go back
to the shop and get the right breaker. A boost transformer and the right
breaker had it working better than it had at their old location, where
it had been on a 208 volt circuit.
For your transformer, all you need is an ohm meter to identify each
winding, and an AC voltmeter to figure out the phasing of each winding.
The logical steps are:
1: Identify the pairs of the thin leads with an ohm meter. These are
the primaries.
2: Identify the pairs of the thick leads with an Ohm meter. These are
the Secondaries.
(BTW, I would put a cable tie around each pair of leads, near the
transformer to keep track of each pair in case you need to reuse it in
the suture.)
3: For 208, connect the two sets of primary wires in series. If you
have 12 volts on the outputs, they are in phase. If not, reverse one set
of the primary leads.
4: Connect a pair of the secondary leads in series. If you get 24
volts, you can use it for 24 volts. If you get zero, connect the
remaining two leads together will give you 12 volts. Just keep in mind
that you only get half the current at 24 volts.
Page 93 of this PDF shows the primaries wired for 120 or 240 and the
secondaries in series or parallel to give 12 or 24 volts boost or buck
<http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=16&cad=rja&ved=0CFwQFjAP&url=http%3A%2F%2Fwww.hammondpowersolutions.com%2Ffiles%2FHPS_Catalog_BuckBoost_Section2.pdf&ei=nr_8Uri1A_fNsQT11YAY&usg=AFQjCNEyTy77_co5ZMOQii2jkEUDw8W1Cw&sig2=-VF-Fyg1XsdHDckcm9EIjw>
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