GEQ 8232 (diodemarked) component

Discussion in 'General Electronics Chat' started by micapp, Apr 18, 2014.

  1. micapp

    Thread Starter New Member

    Apr 18, 2014
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    Anyone who has anything on this one? It is mounted in parallell With a SCR in a batterycharger and may be some overvoltage thing. It has an diode sign on it and is also marked NORBUS 71400L. Any equivalents?
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Could be a Diac, if it is connected to the SCR/Triac trigger.
    Max.
     
  3. micapp

    Thread Starter New Member

    Apr 18, 2014
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    No, its not a diac. It is placed in parallell with anode and cathode of SCR. It is has a case similar to DO-5 (big one).
     
  4. ian field

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    Oct 27, 2012
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    Could be a single package snubber - usually a series CR network.
     
  5. alfacliff

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    Dec 13, 2013
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    also could be a rectifier, sometimes when scr's are used, they dont need full wave control, just a diode across an scr to conduct the other half wave to pass ac.
     
  6. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Yeah that's my guess too. It's common enough practice to put a rectifier diode in reverse parallel across and SCR.

    When the SCR is off the device supplies half wave (half power) and when the SCR is on it runs at full power. Commonly was used for things like dual temperature settings on a heater element.
     
  7. ian field

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    Its always worth giving the datasheet more than a cursory glance - most thyristors are reverse blocking, a few aren't!
     
  8. t06afre

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  9. micapp

    Thread Starter New Member

    Apr 18, 2014
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    Thanks for constructive info. No final solution yet, but I found that 8232 seem to be manufacturing date (week 32, 1982). :):D. Not bad that two of the sets (it is a three phase charger) still works.
     
  10. THE_RB

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    Is this is the secondary of the charger? The low voltage side?

    If so it will use high current low voltage SCRs so the mystery part is likely to be a zener diode to save the SCR from overvoltage.
     
  11. micapp

    Thread Starter New Member

    Apr 18, 2014
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    Yes it is the low voltage side. I also supposed it to be a kind of snubber (TSV-thing). I have checked the advised links, but it does not answer my question. One reason I agrre With you is that I have found that the SCR anode is connected to the diode cathode. I did not see the additional cathode wire earlier because it had been cut very close to the crimping. I can't think of any reason to use a "normal" rectifier like this in a threephase system? The SCR used is a CR101 U04JY and I have found data on this.
    The charger is for a Lansing forklift.
     
  12. MaxHeadRoom

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    Jul 18, 2013
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    What is the nature of the load the SCR's fire into?, is there any heavy inductive or capacitive device, or is it just direct into the battery?
    In Many L or C circuits it is common to place a ordinary rectifier diode in reverse parallel with the SCR for protection.
    Many of the GE and RCA design circuits show this method.
    Max.
     
  13. THE_RB

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    I've seen inside a lot of 3 phase SCR battery chargers, they usually use 3 SCRs and 3 rectifiers, to make a 3 phase controlled rectifier of 6 "diodes" total.

    Can you say if the battery charger has a 3 phase rectifier (6 diodes), AND also has 3 SCRs and 3 mystery diodes?

    Or if it has ONLY the 3 SCRs and 3 mystery diodes?

    A photo would work miracles here. :)
     
  14. micapp

    Thread Starter New Member

    Apr 18, 2014
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    MaxHeadRoom: The thyristor drive the secondary of the transformer directly ("together" With the mystery)
    THE_RB: I will check this, but as far as I can remember, there are three SCRs and Three mystery parts, one for each coil in the secondary winding

    I will come back later today :)
     
  15. micapp

    Thread Starter New Member

    Apr 18, 2014
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    Sorry. I have now dismantled the rectifier unit. It is supplied from a the secondary winding of threephase transformer in starcoupling. What seemed to be one heatsink where the SCR and diode was connected to each other is in fact two isolated heatsinks, one with where the SCR anodes are shorted on and the other where diode cathodes are shorted (from each coil end). From the diode cathode the current flow through a fuse to the battery + and from battery - it returns to the SCR anode (heatsink). Conclusion: This is a normal threephase rectifier system With SCR Control on the Return line. The mystery Component is a normal diode (probably 80A or so)

    Sorry for all fuzz :mad: and thanks very much for Your interrest.:)
     
  16. THE_RB

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    I'm glad you worked it out. Sounds like a standard 3-phase controlled rectifier charger with 3 SCRs and 3 rectifier diodes.

    Here's a common enough example (may help other readers);

    [​IMG]

    They generally follow this format where all 3 SCRs are turns on (or not) as a team, by one simple control voltage or phase pulse.
    :)
     
  17. micapp

    Thread Starter New Member

    Apr 18, 2014
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    A Picture tells more than a thousand Words!
     
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