How to identify the output and input leads & voltage of this device?

Discussion in 'Power Electronics' started by Rahulk70, Mar 15, 2017.

  1. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    Hello guys. I recently got a circuit not sure if its an inverter or a power supply, but searching the model on google gave me results of some other similar products that showed most of them to be power supplies.So, I assumed this to be a power supply too. The manufacturing date on the device shows Dec 1981.It was unboxed for the first time(never used all these years). I'll post a few pics of the Power Supply below.
    IMG_20170315_184455.jpg IMG_20170315_184516.jpg IMG_20170315_184531.jpg IMG_20170315_184552.jpg IMG_20170315_184659.jpg

    The leads on the circuit board as shown in the picture are labeled as -,-S,+S,+.As for the transformer leads pins (1&3) and (2&4) gave me continuity on the multimeter. I'm kinda confused which is the 110/220V pins. My house has both 110V and 220V outputs. What is the -S and +S pins? Also what could be the output voltage? Is it very high like that could electrocute me? I wasn't able to find any datasheet since this is an old circuit as the mgf date says. Any help is highly appreciated.

    Thanks in advance.
    Cheers.
     
  2. WBahn

    Moderator

    Mar 31, 2012
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    From the part number, I would have guessed (and that's all it is) that it is either a 30 V supply with 9 W output rating, or it is a 9 V supply. That large cap is a 25 V cap, so I'm leaning toward it being a 9 V supply.

    The input power can probably be found by tracing the transformer leads. There may be information on the transformer to indicate max voltage rating of the primary (or a part number you can look up).

    The S+ and S- are likely sense leads. So you take power from the + and - leads and connect the S+ and S- leads to the point in the circuit where you want the regulated voltage to appear. This is generally intended to let you remove the effect of lead wire resistance between the supply and the load. If this is not a big issue, then you can just connect S+ to + and S- to -.
     
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  3. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    Thank you. That was really helpful. I was kinda scared since there was no datasheet and the power circuits can be dangerous if you arent't careful. Well 30V or 9V is safe. Also one more question. Can you help me identify the 110V and 220V terminal pairs on the transformer? I got continuity on multimeter for the terminal pairs as follows (1&3) and (2&4). IMG_20170315_184455.jpg

    Thank you.
     
  4. WBahn

    Moderator

    Mar 31, 2012
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    Keep in mind that I said I was guessing -- for all I know it could be a neon sign power supply putting out a few tens of kilovolts with enough current to be fully capable of lighting YOU up. I don't think that's the case, but I can't guarantee it.

    The diagram on the transformer tells you how to connect it. For 115 VAC operation you short pins 1 & 3 and also pins 3 & 4 -- this places the two primary coils in parallel. For 230 VAC operation you short pins 2 & 3 -- this places the two primary coils in series. In either case, your power line connections are applied to pins 1 & 4.

    My recommendation would be short the S+ to + and the S- to - pins and to then put a power cord on it that is several feet long and plug it into a switched outlet. Then turn it on from a safe distance and, if it just sits there looking stupid for several minutes, shut it off and unplug it. Now connect a voltmeter to the + and - leads and set it so that you can read it from a safe distance, plug it back in, and turn it back on. See what the output voltage reads. Worst case is you destroy your meter, so use a cheap one if you can.
     
  5. LesJones

    Well-Known Member

    Jan 8, 2017
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    I would suggest removing the screws holding the transformer so you can read the label on the other side. It should give the seconary voltage and maybe even the current rating.

    Les.
     
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  6. WBahn

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    Good suggestion!
     
  7. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    I tried removing the transformer.Unfortunately there isn't any labeling. The output has totally 4 wires. One thin wire connected to the transformer body. One connected to the + of the big capacitor and another two thick wires connected to the circuit board.
     
  8. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    For the transformer connection did you mean for use on 230V, you link pins 2 and 3 together?And for use on 115V, you link pins 1 and 2 together, and pins 3 and 4 together. That way means the 115V windings act in parallel and don't cancel each other out.
     
  9. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    I have both 110V and 220V output in my house but I'll be using only 110V for safety. I linked 1&2 and 3&4 together. Then I connected my 9V AC transformer to the input i.e 1 and 4 pins. Checked the voltage with my multimeter at input its 8.8V and the output was 1.6~1.7V(Vin/Vout=5.17). and with 2&3 pin(220v setup) output was 0.7V. So, I guess I can safely connect to power outlet now.
     
  10. WBahn

    Moderator

    Mar 31, 2012
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    Look at the wiring diagram provided on the side of the transformer -- it explicitly shows you how to hook it up for each voltage option.
     
  11. WBahn

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    Which output pins were you taking the measurements across? The two going to the circuit board, or one of those and the one going to the capacitor?

    It sounds like it is probably a 22.5 V center-tapped output. That would be consistent with the regulated output being 9 V. The two wires going to the board probably form a full-wave rectifier.
     
  12. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    The output of the transformer has three leads. The centre tap of the transformer output is connected to the + terminal of the big capacitor and I measured the output voltage across the other two terminals.
     
  13. WBahn

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    Mar 31, 2012
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    That's what I guessed was the case.

    As you get further in your exploration of this supply, not that there is a voltage adjust pot on the board. That might mean that the output is adjustable over a wide range, say 3 V to 12 V, or it might mean that it is supposed to be a fixed voltage (say 9 V) but that you have the ability to dial it in very precisely. Note also that it has a pot to adjust the overvoltage protection (OVP) threshold. There are a few ways to implement OVP so you may have to figure this one out through trial and error (or you might be able to ignore it and just treat the supply as not having OVP at all).
     
  14. panic mode

    Senior Member

    Oct 10, 2011
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    1 - 2 is one of primary windings, other is 3 - 4
    if you short 1-2 (say line) and 3-4 (say neutral), it will not work because there is open circuit between the two windings.
    there should be jumper 2-3 regardless which of two AC supply voltage options you use.

    this looks like ancient medical supply. model should be XE<watts>-<volts>
    so XE30-9 is 30W, 9V regulated power supply.
    W/OVP should mean "with over-voltage protection"

    i would not be surprised if IC1 is good old 723
     
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  15. WBahn

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    Look at the wiring diagram on the transformer!

    The windings are 1-3 for one primary and 2-4 for the other. This way you don't have to jumper across another pin -- the jumpers always go between adjacent pins.

    Also, if 1-2 is one primary and 3-4 is the other, then how is it that the TS is measuring continuity between pins 1 and 3 and also between pins 2 and 4?
     
  16. KeepItSimpleStupid

    Distinguished Member

    Mar 4, 2014
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    Line always connects to #1 and #4.

    The 115/230 can be read across as "jumpers". Your basically putting the windings in series or parallel. Quite common.

    S- and - go together and S+ and + go together.

    You have OVP (Overvoltage protection)

    the question is what the model number means. ebay has plenty. Maybe 30 V at 9A with some adjustibility.

    The size of the secondary wires may be able to support 9 Amps. See: http://www.powerstream.com/Wire_Size.htm
     
  17. WBahn

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    I don't think it's 30 V -- the cap is rated at 25 V.

    I think panic mode likely has this correct and that it is a 30 W supply with a 9 V output (so about 3.5 A output).
     
  18. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    Yep. It is a really old supply.The manufacturing date on the power supply says 12-81 which I guess is Dec 1981.Also its damn heavy, heavier than a 500Watt PSU and has much lower current capability.
     
  19. Rahulk70

    Thread Starter Member

    Dec 16, 2016
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    I think its something like this.
    AIc2j.png
     
  20. KeepItSimpleStupid

    Distinguished Member

    Mar 4, 2014
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    Last edited: Mar 16, 2017
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