Galvanic isolation question

Discussion in 'General Electronics Chat' started by Turdnugget, Nov 30, 2013.

  1. Turdnugget

    Thread Starter New Member

    Mar 3, 2012
    23
    3
    Hi,
    I have been studying certain aspects of basic electronics.. Particularly galvanic isolation between 2 ground planes. I understand that it is used to protect low logic components from high voltage as well as other things. Also that without a common you will not get a current loop so there is no current from one isolated circuits positive source, to another isolated ground plane...

    What I'm really curious about is if there is a way around this, is it at all possible to force electrons from one isolated supply into another isolated supply? Without them being able to return.... All in all electron extraction from supply 1 into supply 2... A one way street where you become deficient in electrons for supply 1

    Possibly for a form of positive gas ionization for supply 1's function
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,550
    2,374
    Opto or magnetic coupling.

    The commoning of ground planes can often be done with no ill effect if done properly.
    A typical example of a misinformed effort to employ a isolated circuit is when a desk top PC is used to control an 3ph AC controlled motor such as with a 240vac VFD.
    There is a common practice to use circuitry that outputs the control through the parallel port and a Opto isolator used in order to galvanically separate the PC from the 240vac, whereas in fact the PC power supply is at earth ground potential, as is the 240vAC, via the earthed neutral.
    Therefore the impression galvanic isolation exists, in fact does not.
    Max.
     
  3. Turdnugget

    Thread Starter New Member

    Mar 3, 2012
    23
    3
    That's not the answer that I'm looking for... I know for a fact I can plug in a isolation transformer to house mains that puts out 220volts and I can touch one end of the secondary without receiving 220v shock... Because earth ground is not common to the secondary...

    I also know this is used for supplying power to boats that are connected to land mains power to prevent current loops between the mains voltage and the boats hull.

    My question has less to do with protecting low voltage logics from HV transients, and more to do with making electrons leave one isolated system without returning to where the isolated system which it left can generate positive ions more effectively.
     
  4. #12

    Expert

    Nov 30, 2010
    16,298
    6,811
    Basically, no. If you want to get more specific, you might get a better answer, but hiding behind a hypothetical won't get a circuit working for you.

    We have all kinds of people here, from dead practical to astrophysics theoretical, but you have to be honest and specific about what you want to get the full Monte.
     
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