do we have any electronic engineers please?

Discussion in 'Hobbies' started by acting_strange, Jul 11, 2012.

  1. acting_strange

    acting_strange

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    Sadly I had a little accident with my mini lathe and the speed controller has failed..

    I am trying to find 2 replacments parts for the TIL 113 opto couplers as it appears they are no longer made. Mine are the 6 pin dip dartington pair..

    If anyone could come up with an alternative that I can solder in I would appreciate it...

    Thanks

    Derek
     
  2. Gromett

    Gromett Funster

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  3. acting_strange

    acting_strange

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    Thanks.....I'm having some trouble with the numbers but I agree there are one or two possiblities...
    :thumb::thumb:
     
  4. Gromett

    Gromett Funster

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    It looks like VISHAY SEMICONDUCTOR do direct replacements unfortunately they are at lower ratings than some of the Til 113.

    The continuous forward current is 60ma instead of 100ma. I am not sure what the requirements of your device are? If this is just to generate the signal for a driver transistor or other output device it may be enough. If it is to directly drive a device then probably not.

    http://uk.farnell.com/vishay-semico...n-5300vrms/dp/1612446?CMP=KNC-GUK-FUK-GEN-KWL

    Here is the full range.
    http://www.vishay.com/optocouplers/opto-darl-out/

    It's been a long time since I did any practical electronics but memory seems think that the continuous forward current is the limiting factor in speed controllers providing max voltage is covered.
     
  5. acting_strange

    acting_strange

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    I believe they (there are two), drive two Mosfets that form the drive for a DC motor on my mini lathe....

    Does that make sense?
     
  6. Gromett

    Gromett Funster

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    Yup that makes sense. The FET's will be the output power transistors that control the power to the motors. The gate will have a preset bias and the output of the darlington couple will alter that bias. (roughly speaking)

    It is possible that the TIL component is well over specced and a lower spec component would suffice.

    In the old days of discrete semiconductor components manufacturers would produce one component that would cover a wide range of uses rather than a range of products as it was cheaper on the production line.

    I used to keep a stock of around 8 different transistors for repair TV and video machines and these could be used to fix 99% of problems.

    I realise none of this is any use sorry. Without digging out my electronics books (which are at my nephews) to refresh my memory and seeing the circuit diagram I can't offer specific advice. However in similar use cases the worst that would happen is that the lower rated device if not up to the job would blow like a fuse.

    I would suggest that you check that the pin outs are the same (they are more often than not) Then look at the circuit diagram to see if there is any potential for high voltage to cross the device should it fail. If not (and at your own risk) you could try the lower rated device and it may work or it may pop like a fuse..

    I must point out that I haven't looked at this in any great detail and I am working from memory that is some 20+ years old.

    There must be someone on here who has more recent electronics experience?
     
  7. Gromett

    Gromett Funster

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    Just had another thought. I was thinking this would be PWM controller to ensure full power is delivered even at low rpm.

    If the darlington couple are biased them selves to provide fine motor control then it is likely to require a higher continuous forward current than a PWM type controller. If this is the case then the lower specced item probably wouldn't be up to the job.

    Too many variable to give a proper answer sorry.:cry:
     
  8. hilldweller

    hilldweller Funster Life Member

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    Have a look at TIL111 if they might do PM me your address.

    Tough little buggers opto isolators, if you've killed them that might not be all you've killed.
     
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  9. acting_strange

    acting_strange

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    Yes this is for a PWM controller:thumb:
     
  10. Gromett

    Gromett Funster

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    You are right there. It is however quite easy to blow the darlington transistor pair. I went through a few when making a train controller. The opto isolator part is hard to mess up though:thumb:

    It may work then. I am not familiar with the part Hilldweller mentions. Might be worth having a chat with him as I think his electronics experience is probably more recent than mine..
     
    Last edited: Jul 11, 2012
  11. acting_strange

    acting_strange

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    To be honest I have sent for three ( I always buy in three's when I need two) the price is cheap enough for them to be no good and I will also send for the TIL111's that Brian has mentioned...either way, thank you both very much for the help :thumb::thumb:

    and...here is the wiring diagram for the newer but very similer model...[​IMG]
     
  12. Gromett

    Gromett Funster

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  13. Gromett

    Gromett Funster

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    I must be going blind. I can see all the OP amps for comparitors and oscillator but I can't see the opto isolation there or the mosFET output stage:Doh:
     
  14. acting_strange

    acting_strange

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    Sorry...wrong diagram...:Doh:

    If you type FC250J into google it will bring up masses of info...
     
  15. acting_strange

    acting_strange

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    Here is a hand drawn one...[​IMG]
     
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  16. acting_strange

    acting_strange

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    What about a 4N25??
     
  17. Gromett

    Gromett Funster

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    Working through it. Missing a key for custom markings. And it looks back to front. Input on left output on right. Not used to working that way:Rofl1::Rofl1:

    I will see if I can make head or tails of it..
     
  18. Gromett

    Gromett Funster

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    Sorry the circuit diagram just looks wrong..

    There is a relay coil prior to the bridge rectifier but it doesn't tell me which contacts this operates.

    It indicates that the input is AC but what voltage. There are relays before the bridge rectifier.

    The forward reverse switch below the relays (before the bridge) doesn't appear to do anything unless it is a double pole switch linked to the one to the left of the diagram.

    What are P1, P2, P3 and P4 in circles? Either this is a custom notation or my memory has leaked :Doh:

    There are no voltages marked. But judging by the components ratings it is 24 volt AC input? It looks to be split so provide a virtual ground in the middle giving -12/+12V?

    Grrr. I need a break. I will come back to it when my heeed isn't fried.
     
  19. Gromett

    Gromett Funster

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    Ok. final couple of notes.

    1) the Zener diode that is setting the collector voltage on the darlington pair is at 18V. The output voltage of the H11B1 says 25V so you should be clear there I think.

    2) I can't see the oscillator for the PWM generation. Is this on another board?

    3) There doesn't appear to be any smoothing cap or voltage regulation on the input to the circuit (after the bridge rectifier).

    4) He has no dots or bridge symbols for where wires cross or join. This makes some of the circuit hard to deduce.

    Anyway, off for some food will have a look again later...

    If you can find a better circuit diagram it would help. Also details of what the inputs are...
     
  20. acting_strange

    acting_strange

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    More to follow..
     
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