Isolation transformer question

Discussion in 'General Electronics Chat' started by Gated, Jul 27, 2010.

  1. Gated

    Thread Starter New Member

    Jul 7, 2010
    Hello everyone,

    As we all know, an isolation tranformer is wound with a 1:1 ratio, however, I wondered, I have a 240V to 120V transformer (40 amps output), although it has multiple taps, (it has a 400V primary), I wondered if it can achive simular properties as an isolation transformer? or do I specificly need a seperate true 1:1 transformer along with this one to get proper isolation?


  2. beenthere

    Retired Moderator

    Apr 20, 2004
    As long as the primary does not have a connection to the secondary as in an autotransformer, you do get galvanic isolation. This thing is still a monster, so the output is going to be awfully lethal. The use of a GFCI outlet with a solid ground would be a good idea for safety.
    Gated likes this.
  3. Gated

    Thread Starter New Member

    Jul 7, 2010
    okay, makes sence,
    thank you for your responce.
  4. timrobbins

    Senior Member

    Aug 29, 2009
    Sometimes the reference to an 'isolation' transformer means more than just a simple power transformer with galvanic isolation between primary and secondaries. 'Isolation' often infers it has additional screens than just the PE screen, and often infers it has a higher level of insulation rating - typically specified by higher voltage withstand rating bw PRI and SEC (eg. 5kVrms 1 min flash).

    Ciao, Tim