109/111 New Oxford Street, London
Lahmeyer Electrical Co supplied electrical equipment to David Davis and Sons for their Ferndale Collieries. This included three Lahmeyer flywheel generators working at 2200 volts, 25 Hz, 3-phase driven by Sulzer Bros cross-compound 2500 HP engines. See photographs. Lahmeyer also supplied, for the No. 9 Pit, the first electric winding machinery to be operated in the South Wales Coalfield. It worked on the Ilgner System, with a 16-feet parallel drum coupled to two direct current motors mounted on either side, each giving a maximum output of 1,250 HP. The DC current for driving the winder motors came from a large Ilgner Motor Generator, consisting of a three-phase 2,200 volt motor (750 HP) driven direct from the power station supply. A DC generator supplied the winding motors, and there was a large cast steel flywheel, weighing approximately 30 tons, coupled on the same shaft, to supply the necessary power to the DC Generator in excess of that supplied by the three-phase motor in order to generate sufficient power for the winder-motors during the early part of the wind, when the load was very heavy. The flywheel had a maximum speed of 500 rpm, and had the effect of equalizing the load taken from the power station. The flywheel was 13 feet diameter, and 3 feet wide on the rim.