Thread: isolation transformer
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Michael A Terrell Michael A Terrell is offline
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Default isolation transformer
wrote:
On Thursday, 7 December 2017 21:17:18 UTC, Michael Terrell wrote:
tabbypurr wrote:
On Tuesday, 28 November 2017 23:08:59 UTC, whit3rd wrote:
On Tuesday, November 28, 2017 at 12:48:01 AM UTC-8, GS wrote:

Commercial isolation transformers get rid of common mode noise, and
since one leg of output is tied to ground, forms a new local
neutral.

That's only true of SOME isolation transformers; the ones used for
bench safety when working on live equipment do NOT make the
neutral-ground connection.

Quite. And building site transformers earth the centre tap.


IOW, they convert the European 240volt system to the American
120V/240V system.

They output 110v centre earthed, so nothing is over 55v ac from ground. It was the building site standard until RCDs made 110v not really needed.


Unless they didn't want to replace all their existing power tools?

The wiring is US, even if the transformer is only 50%. Not all of our
power tools are 120 VAC. Some are 240, and others are 480 VAC, three phase.

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