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Can you ID this transformer

Discussion in 'General Electronics Discussion' started by Woodman, Dec 10, 2012.

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  1. Woodman

    Woodman

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    Dec 3, 2012
    Found this in the basement. Not sure where it came from, possibly an old copy machine. I googled the markings (PO187FC and 17V2ZD) and came up with blanks.

    PICS attached
     

    Attached Files:

    Last edited: Dec 30, 2012
  2. KJ6EAD

    KJ6EAD

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    Aug 13, 2011
    This is thin but the markings look like they could be Stancor. Have you identified the windings and any taps yet?
     
  3. Woodman

    Woodman

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    Dec 3, 2012
    No clue. It is very heavy for such smallish windings. I can't even tell for sure if step up or down or neither. Best guess is that the outer windings are very slightly thicker than inner windings. I'm a greenhorn and am wondering if it would be ok to plug AC line into what may be primary while having voltmeter measuring other end for a second or two?
     
  4. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    If by "OK" you mean "safe", then no.

    The best thing is to connect a low voltage AC into the winding with the highest resistance and read to voltages from the others.

    From that you'll get an idea of the turns ratio(s).
     
  5. Woodman

    Woodman

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    Dec 3, 2012

    The secondary outer windings with a magnifying glass were noticeably wider. So hooked up 120 volts to primary and plugged into wall via a Watt-O-Meter. Also attached a 25 watt bulb to secondary and measured volts and amps at same time. Here are the measurements on primary side and secondary side: {See picture}

    1. Primary - Watt-O-Meter shows 122 volts, .3 amps, and 13 Watts (these don't look right -but that's what it said)?
    2. Secondary - multimeter shows 26 volts and bulb was very dim though not quite as dim as it looks because of camera flash. Amps fluctuated between neg and pos but were hardly measurable (approx .1 milliamp). There are 35 volts without bulb attached.

    Since this may have been from a very old copy machine, maybe 220 or 440 volts should be the input. Short of inputting 220 volts, how can I get more power out of this thing?

    This thing weighs over two pounds so, I would think it should get at least 60 watts, not the approximately 2 watts it is getting. Transformer is still ice cold after running for half an hour! What am I missing?

    Woody
     

    Attached Files:

    Last edited: Dec 13, 2012
  6. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    OK, so you decide not to listen to advice.

    You will also probably ignore the advice that connecting up a 25W 120V globe to a 26V winding is not exactly a great load test.

    The results you're getting are what I would expect. Why would you expect a bulb that dissipates 25W at 120V to dissipate 60W at 26V?

    Most of the 13W you're seeing are probably losses in the transformer. What does it read when the bulb is disconnected (Not that I'd advise you to be playing with 120V)

    There also seem to be more windings than you've mentioned. Have you read the voltage on all of them? Warning, since you have ignored my earlier warning, these other windings may be dangerous.
     
  7. Woodman

    Woodman

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    Dec 3, 2012

    Steve, didn't know how to input small ac voltage, and thought windings ratio to be good enough to try a test. Volts with no load were 35. The primary taps all have same ohms (9) so fingured they were just extra taps. Secondary ohm was four. Wanted to use car dome light but misplaced it -did not think about AC lamp needing 115 volts. :-(
    There is not much copper on these windings so I'm beginning to think it is mostly a low power lump of steal.

    Woody
     
    Last edited: Dec 13, 2012
  8. KJ6EAD

    KJ6EAD

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    Aug 13, 2011
    Let me rephrase. Have you identified any of the windings and taps to us? For example, you might say "the transformer has X wires going into 2 connectors. 3 go to the first connector and Y go to the second. The 3 wires on the first connector are colored black, red and red. I have used an ohmmeter to determine that the red wires are the ends of a single winding and the black wire is a center tap for that winding. The total resistance is Z. The wires on the second connector are..." or something to that effect. A little diagram with colors, connections and resistances would be a bonus.
     
  9. Woodman

    Woodman

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    Dec 3, 2012
    The picture probably shows better than I can explain but will try. The transformer has seven wires going into 2 connectors. The primary connector has four wires attached:

    White wire taps to beginning of primary wire, the next three primary wires also attach to primary connector (brown, blue, black).. The last (5th) primary wire is also black and for some reason goes into the secondary connector. Measuring from the white wire connector the ohms are 9 to each of the above four wires.

    The secondary has two wires coming out of it. One red is the beginning of secondary wire and other red wire is end of secondary wire. The secondary connector has three wires attached. The two reds and, as mentioned above, a black wire from primary. Red to red show 4 ohms, and open from reds to black, so again don't know why this wire was placed on secondary, other than primary has 5 wires and primary connector had only four slots and the secondary connector had two open slots..

    The car lamp was 12 volts and when attached to secondary, it lite very brightly and blew quietly, instantly. How do I find the VA rating of transformer? What would happen if I attach a large 15 watt 2.7 ohm resistor from a old tv to the secondary -would that blow up in my face? Guess I need to attach some kind of load that would drop voltage from 36 unloaded to about 24 volts loaded. Don't have anything that runs on 24 volts. Since this may be an old copy machine transformer, possibly it was used for powering 24 volt lamps or maybe a very small 24 volt motor, or something else. What uses can you think of for this transformer?

    Woody
     
    Last edited: Dec 30, 2012
  10. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    I prepared an answer yesterday, but KJ6EAD got in before me with essentially what I was asking for.

    Your explanation is still unclear. It is especially unclear where you talk about the secondary. The images you provide don't really seem to help either (they only show the primary)

    OK, if all the primary leads show 9 ohms WRT the white lead, you need to look more carefully at the taps. Presumably the white wire seems to attach to a single wire. Al of the others (except 1) will look like they connect to 2 wires. You need to find the other one which attaches to only 1 wire.

    It sounds like the primary may be something like 0-90-100-110-120 or similar.

    Please remember that the primary leads that you do not connect are dangerous (and could kill you). I recommend that you (at least) cover them with tape if you're not connecting them to the mains (which I still consider less than safe).

    If the secondary sounds confusing. You seem to be indicating that there is a position for another wire? Do each of the existing wires connect to a single wire going into the transformer, or does one connect to a pair of wires?

    Don't just go connecting random loads to the transformer. This won't tell you anything about its ratings.

    The first thing to do is to establish which the correct primary and secondary connections are.

    As I said VA rating can be estimated by comparing the weight of this transformer with the weight of a known transformer of similar construction.
     
  11. Woodman

    Woodman

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    Dec 3, 2012
    Stevo, I admit that old pictures "hide" secondary. {see new pics} hopefully this is more clear (the secondary wraps around primary, is not over/under like many designs).

    Does not seem to matter what tab I connect white primary to. Any of the four other primary tabs give about same result. Could very well be 90-100-110-120. But even 120 probably provides very little amperage. In fact, Watt-O-Meter only showed a 1 watt usage difference between tap closest to white tab and farthest. Any suggestions on further load testing, and any ideas what this could be used for?

    Woody
     

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    Last edited: Dec 14, 2012
  12. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    Your watt-o-meter is not useful. Put it away!
     
  13. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    You say "about the same result". This tells me the results are different. What are they?
     
  14. Woodman

    Woodman

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    Dec 3, 2012
    Specifically, as I should have originally said, the bulb is very dim on all settings. Amps were hard to measure yesterday because AC amps fluctuate on my meter, ampmeter bounced between +.1 and -.1 milliamps when loaded with a 25 ac bulb load on all dc posts. Assuming 30 volt output, and the above .0001 amps that is only .003 Watts!

    I just took some unloaded secondary volt measurements from all four primary posts and they were:
    From white to brown 35.1, white to blue 31.8, white to black 29.2, and white to 2nd black also 29.2 -all unloaded. Don't remember for sure, but yesterday I only saw 25 volts on secondary from at least two different primary volt tabs when loaded.

    Can someone explain to a greenhorn like me what is going on here? Is this just a 2 pound lump of steel with very little juice or can it safely run maybe 25 watts?? It blew out the car dome light in a nice bright flash so maybe there were several real watts running there for a split second? Either way, what would be some practical things one would make with this transformer?

    Woody
     
    Last edited: Dec 15, 2012
  15. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    As I have said on a number of occasions, put your watt meter away, don't try to measure the current, it's not telling you ANYTHING about the transformer. All it's telling you is about the load.

    OK, that is what I call a significant difference -- 20%. I'm guessing the taps are for 90, 100, 110, and 120V.

    I'd guess that the transformer has a secondary voltage of around 30VAC -- the exact rating may never be known.

    You say that it weighs about 2 lbs (let's say that's 900g) -- My guess is that a safe secondary current is around 1A -- call it 30VA

    You are connecting a voltage to the primary of a transformer where you do not know what the primary voltage is rated for and then placing a random load on the secondary and assuming that this will tell you something about the power rating of the transformer.

    Well, transformers don't "run 25W" but I know kinda what you mean. The answer is "quite probably".

    It's just that the random load you selected here was rated at a lower voltage than the transformer and it blew. The other random load was rated for a far higher voltage and was very dim.

    All that told you was what you could easily assume; running a 120V globe from 30V is not going to work real well, and a 12V globe being powered from 30V is going to have a very short (but brilliant) career.

    As you see, neither told you anything that your voltmeter didn't already predict.

    Given your apparent skill with electronics, I'd say "nothing without supervision".

    With the assistance of someone appropriately skilled, you could make a small power supply perhaps.
     
  16. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    Doesn't the plate on the xfmr say 17V?
     
  17. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    yeah, but the measured output voltage seems too high for that.

    if it is a 17V secondary it implies the primary is 60 - 80V.

    And that is assuming it's actually a power transformer (although it seems likely)
     
  18. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    Like an idiot I Googled the part number. Anyone surprised I didn't get any hits?

    Chris
     
  19. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

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    We already know that you're getting ~30V out for 120V in. Reversing the transformer could give you in the region of 480V.

    Even IF this were the way the transformer was designed to be used, the voltage is probably too high for any practical (simple) project, and way too dangerous to be poking your fingers around.
     
  20. Woodman

    Woodman

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    Dec 3, 2012
    Steve, have no intention of following his advice. 120 volts is already more that I can handle. :)

    I have a schematic for a battery charger and I was wondering if I you'd be willing to look at it? Manufacturer says it is for private use only so would rather not post on web. Is there another way to contact you, or if not could you recommend someone else?

    Woody
     
    Last edited: Dec 16, 2012
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