The only difficulty he might have is the transformer will not like having it's
power turned on and off like that.  You may need extra circuitry to avoid the
resulting surges and noise...

-Adam

Wagner Lipnharski wrote:
> Suppose you connect a 400V x 8A triac (Q4008L4-ND Digikey $2.00) in
> series with the primary to the 117Vac. Suppose you connect this triac to
> keep conducting all the time, using a resistor between Anode and Gate,
> then you connect the output side of an opto-coupler to switch off (when
> active) the triac.