On 2012-10-13, Jim Wilkins wrote:
"DoN. Nichols" wrote in message
....

You can't -- but there are 240 V rated ones with a center tap so
you can feed them from 120 V and still get the whole range.


I've got one of those that has considerable output droop under load
above the tap. IIRC the max current falls from 10A at the tap to
about 6A at the top end. I don't have it wired up in an enclosure, and
I'm not about to power it up exposed on the bench.

If the feed is at a 120 V tap, and the maximum voltage is 140 V,
I would expect the maximum output current to drop to 8.57A, not all the
way to 6A.

If the input tap is nominally 110 V, then the 140 V output should
be 7.86 A.

If the maximum output is something other than 140 V, then it all
needs re-calculation. :-)

But essentially, you divide the nominal current by the ratio
between maximum and input tap to get the safe output current.

Essentially, make sure that neither the input current or the
output current exceeds the nominal 10A -- check *both* to be sure.
(This is why a fuse on each. :-)

Enjoy,
DoN.

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