Lundahl C-core mains transformers use a very small
air-gap is used to compensate for any DC unbalance
in the mains outlet.
Secondary voltages listed are no-load voltages.
drop because of load is to be calculated from
transformer copper resistance and load current.
Electrical size is estimated to 250VA, which can
be increased with good cooling. For optimal use,
about 75% of power should be taken from secondary
should be connected in series for 210 - 250 V,
in parallel for 105 - 125V. Table entries are
calculated for primary voltage 230 V.