how to id transformers ?

[robb]

i have a couple of mystery transformer pulls {microwave, vcr,
clock radio, etc}
i try to google codes on trans with no proper hits ...

how to id these transformers ? is there a way ? do the numbers
have significance on there own ?

i want to figure/estimate the ratings they might be useful for ?
thinking of using in power supply ?

eg, one T has
9199-207-029
41B512
DY 217 B

2 sets of windings around standard type metal core - B
1 winding has 2 white, 1015 - 22 AWG wires connected
other winding has two yellow and two red 1007 - 22 awg wires
coming out
when i apply 115 Vac to the white wires i get 15 Vac out of red
and 3 Vac out of yellow wires


thanks for any ideas / info,
robb

 

[Eeyore]

robb wrote:

i have a couple of mystery transformer pulls {microwave, vcr,
clock radio, etc}
i try to google codes on trans with no proper hits ...

how to id these transformers ? is there a way ? do the numbers
have significance on there own ?

None whatever.

The part numbers are usually unique to the manufacturer. The best you can hope
for is a label with the voltages.

Graham

 

[Michael Black]

"robb" (some@where.on.net) writes:

i have a couple of mystery transformer pulls {microwave, vcr,
clock radio, etc}
i try to google codes on trans with no proper hits ...

If you're taking them out of things, then don't merely take them out

of things. Mark them with what you took them out of. Mark which
side connects to the AC line. Even trace out some of the secondary
to see what's there.

What something is used in originaly gives a clue to what it's good
for. A microwave oven transformer is pretty specialized, high voltage
and with limitations for other uses. A transformer in a clock radio
will be relatively low voltage, and relatively low current, but often
useful for powering various simply projects.

Knowing which is the primary (there is sort of a color code but
it's not always used), then you can at leats hook it up to the AC
line and measure the secondary voltages. Be careful, since if you
don't know where it comes from, you can't rely on the voltages
being safe.

You can do this without knowing which is the primary, but
it's risky since if you connect the wrong winding to the AC line,
then the step up from a low voltage winding to the real primary can
result in a quite high voltage on that real primary. SOme would suggest
if you don't know the primary, use a low voltage transformer to feed
the unknown winding until you figure out the primary by looking at the
relative voltages out of the rest of the windings.

Tracing out the general circuit will give you an idea of the voltage
coming out, and maybe more important the current. Current isn't easy
to judge merely by looking at the transformer, though presumably the
bigger the transformer for a given voltage output the higher its
current capacity. But if you trace the circuitry a bit, you may
see clues to what its expected to supply current wise. If there's
only one winding and it goes to a low current regulator, that says
something as does going to a to-220 or to-3 packaged regulator. It
won't give you exact, but it will give you clues.

Michael

 

[GregS]

In article <13ksejqguiibcd0@corp.supernews.com>, "robb" <some@where.on.net> wrote:

i have a couple of mystery transformer pulls {microwave, vcr,
clock radio, etc}
i try to google codes on trans with no proper hits ...

how to id these transformers ? is there a way ? do the numbers
have significance on there own ?

i want to figure/estimate the ratings they might be useful for ?
thinking of using in power supply ?

eg, one T has
9199-207-029
41B512
DY 217 B

2 sets of windings around standard type metal core - B
1 winding has 2 white, 1015 - 22 AWG wires connected
other winding has two yellow and two red 1007 - 22 awg wires
coming out
when i apply 115 Vac to the white wires i get 15 Vac out of red
and 3 Vac out of yellow wires


thanks for any ideas / info,
robb

As said, scope out everything. I would assume you allready
have a understanding of transformers. if ou look at the wire,
you might get a rought idea of its capabiliries, but it
could also throw you off. As said in the sci repair faq, I
gave a simple way to estimate output current ratings. You
simply load the output untill it drops 15% in voltage and montor voltage
and current. A very good transformer can have a 10% drop rating.
A very poor one can go up to 30%. 15% is an average figure.
Let it run for a length of time and also monitor temperature.
Back off and you should be OK.

greg

 

[robb]

"Michael Black" <et472@FreeNet.Carleton.CA> wrote in message
news:fim9hl$bbu$1@theodyn.ncf.ca...

"robb" (some@where.on.net) writes:
i have a couple of mystery transformer pulls {microwave, vcr,
clock radio, etc}
i try to google codes on trans with no proper hits ...

If you're taking them out of things, then don't merely take
them out
of things. Mark them with what you took them out of. Mark
which
side connects to the AC line. Even trace out some of the
secondary
to see what's there.

What something is used in originaly gives a clue to what it's
good
for. A microwave oven transformer is pretty specialized, high
voltage
and with limitations for other uses. A transformer in a clock
radio
will be relatively low voltage, and relatively low current, but
often
useful for powering various simply projects.

Knowing which is the primary (there is sort of a color code but
it's not always used),

[trim more details]

Thanks Michael,

I was hoping the numbers on the transformers were some sort of
encrypted code or P/N that i could decipher /use to find specs.
when i pulled them i did look at what was connected but months go
by then all i can remember is what they came out of.

Is there a way to make an experimental survey or educated gues of
a transformer's limits/specs without frying the transformer in
the process ?

ideas like the size of wires or the weight of the transformer ,
maybe some simple stress and stability measures , feed a variety
of inputs Hz/Vac deltas and plot input vs outputs then find some
ideal function/curve that defines upper/lower bound limits of a
transformer ?

this is more for eductional instruction/experimentation than for
practical use

thanks for help ,
robb

 

[robb]

"GregS" <zekfrivo@zekfrivolous.com> wrote in message
news:fiml5d$6i0$1@usenet01.srv.cis.pitt.edu...

In article <13ksejqguiibcd0@corp.supernews.com>, "robb"
some@where.on.net> wrote:
i have a couple of mystery transformer pulls {microwave, vcr,
clock radio, etc}
i try to google codes on trans with no proper hits ...

how to id these transformers ? is there a way ? do the
numbers
have significance on there own ?

i want to figure/estimate the ratings they might be useful for
?
thinking of using in power supply ?

eg, one T has
9199-207-029
41B512
DY 217 B

2 sets of windings around standard type metal core - B
1 winding has 2 white, 1015 - 22 AWG wires connected
other winding has two yellow and two red 1007 - 22 awg wires
coming out
when i apply 115 Vac to the white wires i get 15 Vac out of
red
and 3 Vac out of yellow wires


thanks for any ideas / info,
robb

As said, scope out everything. I would assume you allready
have a understanding of transformers. if ou look at the wire,
you might get a rought idea of its capabiliries, but it
could also throw you off. As said in the sci repair faq, I
gave a simple way to estimate output current ratings. You
simply load the output untill it drops 15% in voltage and
montor voltage
and current. A very good transformer can have a 10% drop
rating.
A very poor one can go up to 30%. 15% is an average figure.
Let it run for a length of time and also monitor temperature.
Back off and you should be OK.

greg

Thanks greg,

i just posted a reply question regarding what you have just
pointed out.

so i get a variable current load and monitor current, voltage and
temperature until i see drop of 15% in output (or temperature of
???) as a average target for upper bound current limit.

regarding temperature, is there a typical operational rating
value for most basic average transformers ?

thanks again, i will go visit the repair faq,
robb
c

 

[GregS]

In article <13ktmvgl4938409@corp.supernews.com>, "robb" <some@where.on.net> wrote:

"GregS" <zekfrivo@zekfrivolous.com> wrote in message
news:fiml5d$6i0$1@usenet01.srv.cis.pitt.edu...
In article <13ksejqguiibcd0@corp.supernews.com>, "robb"
some@where.on.net> wrote:
i have a couple of mystery transformer pulls {microwave, vcr,
clock radio, etc}
i try to google codes on trans with no proper hits ...

how to id these transformers ? is there a way ? do the
numbers
have significance on there own ?

i want to figure/estimate the ratings they might be useful for
?
thinking of using in power supply ?

eg, one T has
9199-207-029
41B512
DY 217 B

2 sets of windings around standard type metal core - B
1 winding has 2 white, 1015 - 22 AWG wires connected
other winding has two yellow and two red 1007 - 22 awg wires
coming out
when i apply 115 Vac to the white wires i get 15 Vac out of
red
and 3 Vac out of yellow wires


thanks for any ideas / info,
robb

As said, scope out everything. I would assume you allready
have a understanding of transformers. if ou look at the wire,
you might get a rought idea of its capabiliries, but it
could also throw you off. As said in the sci repair faq, I
gave a simple way to estimate output current ratings. You
simply load the output untill it drops 15% in voltage and
montor voltage
and current. A very good transformer can have a 10% drop
rating.
A very poor one can go up to 30%. 15% is an average figure.
Let it run for a length of time and also monitor temperature.
Back off and you should be OK.

greg

Thanks greg,

i just posted a reply question regarding what you have just
pointed out.

so i get a variable current load and monitor current, voltage and
temperature until i see drop of 15% in output (or temperature of
???) as a average target for upper bound current limit.

regarding temperature, is there a typical operational rating
value for most basic average transformers ?

thanks again, i will go visit the repair faq,
robb
c

We all like the transformers to not get hotter than what
you can easily hold your hand on, but they can get hotter.
When it starts to smell, your probably going too far !!
There are transformers that have a temperature cut out,
and it will usually make the unit unopperative unless,
you can cut away the insulation and expose and replace it
or bypass it.

greg

 

[Peter Bennett]

On Thu, 29 Nov 2007 10:27:44 -0500, "robb" <some@where.on.net> wrote:

I was hoping the numbers on the transformers were some sort of
encrypted code or P/N that i could decipher /use to find specs.
when i pulled them i did look at what was connected but months go
by then all i can remember is what they came out of.

I expect that power transformers in most consumer products will be
custom-designed for the particular application. Any numbers on them
will be the equipment manufacturer's part number. Specifications are
unlikely to be available.

Is there a way to make an experimental survey or educated gues of
a transformer's limits/specs without frying the transformer in
the process ?

ideas like the size of wires or the weight of the transformer ,
maybe some simple stress and stability measures , feed a variety
of inputs Hz/Vac deltas and plot input vs outputs then find some
ideal function/curve that defines upper/lower bound limits of a
transformer ?

I suggest you look at a transformer manufacturer's catalog (see
http://hammondmfg.com/5cindex.htm, of example) and compare the size
and weight of your transformers to their products to get an estimate
of the power ratings.

this is more for eductional instruction/experimentation than for
practical use

thanks for help ,
robb

--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
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