Working from what he considered an impractical Gaulard-Gibbs design, electrical engineer William Stanley, Jr. developed what is considered the first practical series AC transformer in 1885. Working with the support of George Westinghouse, in 1886 he demonstrated a transformer based alternating current lighting system in Great Barrington, Massachusetts. Powered by a steam engine driven 500 V Siemens generator, voltage was stepped down to 100 Volts using the new Stanley transformer to power incandescent lamps at 23 businesses along main street with very little power loss over . This practical demonstration of a transformer and alternating current lighting system would lead Westinghouse to begin installing AC based systems later that year.