Ground one side of isolation xmfr?

[Eric R Snow]

I'm using a stepdown xmfr to get 110 from 220. Should one leg of the
uotput be grounded? The 110 will be used to power a computer and some
contactors.
Thanks,
ERS

 

[Dimitrij Klingbeil]

"Eric R Snow" <etpm@whidbey.com> wrote in message
news:81butvs6p3gpujblbt18r93l615r1oh60u@4ax.com...

I'm using a stepdown xmfr to get 110 from 220. Should one leg of the
uotput be grounded? The 110 will be used to power a computer and some
contactors.

Not necessary. Just ground the computer (or whatsoever) properly, that's
all. Don't forget to ground the metal case of the transformer however (if
applicable). Note that you may want to use a basic capacitive hi-freq filter
to assess RFI problems (if any come up). In this case, 3 small HV caps
(something like 0.047uF 2000VAC) are connected between the ground and the 2
output leads like a triangle.

Dimitrij

 

[John Popelish]

Eric R Snow wrote:

I'm using a stepdown xmfr to get 110 from 220. Should one leg of the
uotput be grounded? The 110 will be used to power a computer and some
contactors.
Thanks,
ERS

I would ground one side to create a neutral (grounded current carrying
conductor). Without this, there is an indeterminate (and possibly
damaging) amount of voltage in common on both legs of the output,
caused by leakage and static sources. You wouldn't want leakage from
the CRT high voltage supply finding its way back into the common power
supply lines and arcing over the computer power transformer.

--
John Popelish