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David Nebenzahl David Nebenzahl is offline
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Default Magnetic vs electronic transformer?

On 4/7/2008 1:02 PM Dave Martindale spake thus:

Don Wiss writes:

MAGNETIC TRANSFORMERS operate at standard low frequencies (5O/6O Hz). They
offer very reliable operation and are very durable, Since magnetic
transformers operate at low frequencies, they experience much less vo1tage
drop over a long distance compared to high frequency electronic
transformers.


[...]

Hmm. This says that the transformers have relatively poor regulation
due to high internal resistance, so output voltage drops with load, and
that they have compensated for this by making the open-circuit output
voltage higher. This probably does give the smallest, least expensive
transformer for a specific load that the transformer is matched to.
But the transformer is likely to run hot at that load.

I wonder if there are other suppliers that sell lighting transformers
whose open circuit voltage is just 12 V, with better regulation so the
output voltage falls less with increasing load. Such a transformer
could be used for any load, from a single lamp up to full rated output.
It would run cooler too, with lower losses at full load. But it will be
larger (larger diameter copper, or fewer turns of copper which requires
more iron) than the transformer with poorer regulation.


Regulation, schmegulation.

I wouldn't sweat that part of the equation; this is far from a
high-precision system, and a little variation, or even fluctuation, of
voltage isn't going to make any perceptible difference. The load, after
all, will be fixed, once the O.P. gets all the lamps installed, so a
common ordinary transformer will work just fine here.


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