The Collaborative International Dictionary of English v.0.48:
Amperage \Am*per"age\, n. (Elec.) The strength of a current of electricity carried by a conductor or generated by a machine, measured in amp[`e]res. [Webster 1913 Suppl.]WordNet (r) 3.0 (2006):
amperage n 1: the strength of an electrical current measured in amperes