Company 51 was dispatched to Building 45 for the automatic fire alarm in the mechanical room. E-751 arrived on the scene to investigate and was met with heavy smoke conditions upon arriving at the reported location of the building. Command was established by Chief 751-D at side "A" of the building. After a quick recon of the room it was determined that he fire was caused by an elevator motor on fire in the room. The utilities to the room were quickly secured and fire was then extinguished. The crews worked to ventilate the room prior to returning to service. The responding crews were : Engine 751: OIC-MFF Boyle, DR-Tech. Bede, RB-Tech. Thomas, A-751: OIC-MFF Kellum and DR-Tech. White, and Chief 751D-Capt. D'Ambrosio.