We are Ass-u-me-ing that by "off this transformer" you meant on the load (low voltage) side.
Quick, dirty and rough* estimate using the "infinite bus" method, which means we ignore upstream issues and assume unlimited SCA on the line side.
45kVA
Ass-u-me-ing 120/208V secondary
Ass-u-me-ing 5.75% Z
Ass-u-me-ing std efficiency
208V FLA = 125A {45kVA/(.208 x 1.732)}
SCA = (125 x 100) / 5.75
SCA, worst case scenario, = 2,173A
Motor contribution may take it up a notch, but not much.
Wire impedance may take it down, probably more than any motor contribution anyway.
Bottom line, not even close to 14,000A. Where did that number come from? Was that the SCA on the LINE side of the transformer? If so, the SCA on the secondary would be even lower.
*How I like my women too...