grounding

Discussion in 'General Electronics Chat' started by prajk, Nov 13, 2007.

  1. prajk

    Thread Starter New Member

    Nov 13, 2007
    4
    0
    hello,
    i m using a driver card and processor card. when i used to give then same supply that time my driver card was working fine and processor card used to blow so i used isolation patch of optoisolators but problem is that my processor card is fine and ics and supply fuse of driver card are blowing. i m also giving the proper earth ing to driver card but still it is not working. is it a problem of virtual ground? due to which my supply current is more
    pls help thank u
     
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    We don't know what device you are speaking of. Some further information beyond the equipment type would be nice, too - you say the processor card was "blowing". Was that a fuse, or some device on the card. Now the driver card fuse is blowing - what does the driver card do?
     
  3. prajk

    Thread Starter New Member

    Nov 13, 2007
    4
    0
    sorry for incomplete info
    patch that we use for processor card i.e. microcontroller was blowing
    and after isolation driver card has problem, driver card is used to operate the motors
    signal for enable direction and clock are sent to drver card we are using L297 and L298
    driver card also has its own 5 v supply for that we use 18v transformer and fuse of 2amp
    after isolation that fuse blows or ics on the drver card blow
    -is it due to signals from microcontroller or any ground issue???
     
  4. prajk

    Thread Starter New Member

    Nov 13, 2007
    4
    0
    can i use zener diode at the output of supply voltage so that it will maintain the supply constant
     
  5. beenthere

    Retired Moderator

    Apr 20, 2004
    15,815
    282
    With no more information than we have, it is not possible to diagnose the problem. We would need circuit details, as well as some idea of the load/s the isolated drover board is handling. If the load/s operate with a separate ground, the isolation must be good or problems will arise.

    Getting 5 volts off an 18 volt source means a lot of power wasted in the regulator. The best situation is where the supply voltage is only 2 - 3 volts above the regulated output. If you are pulling 2 amps, then the 13 volts dropped at the regulator means 26 watts waste heat to dissipate. That could have something to do with the failures.
     
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