Technical Specifications - 2.1. Power Transformer Rating Data A. Quantity, rating, and any other specific requirements shall be provided in the purchase order. B. Cooling Class i. All transformers are to be ONAN/ONAF/ONAF cooling class unless otherwise specified. ii. All fan motors are to have separate grounding conductors. iii. Vibration damping is to be provided between the fans and radiators. iv. Fans are to be dynamically balanced to reduce vibration and motor bearing wear. v. Fan motor leads shall be weatherproof. The connector, plug, and receptacle assemblies shall be of non-corrosive metal, weather tight, and have non-corrosive contact assemblies. vi. Fan blades are to be aluminum alloy, stainless steel, or other corrosion resistant metal, and designed to minimize noise. vii. Fan guards are to be metal and hot dipped galvanized, PVC coated, or stainless steel, and shall satisfy OSHA requirements. viii. An ON-OFF-AUTO control switch shall be provided for independent control of each cooling stage. This control switch shall not have an "off'' position. ix. Fans shall be located such that the transformer does not need to be de-energized to repair or replace a fan. x. Loss of cooling power supply alarms shall be provided. xi. A contact that opens on the main tank low oil level must be provided. xii. Valves to isolate coolers, pumps, and radiators are required. xiii. Each radiator, cooler, or heat exchanger shall have a minimum of 1" vent plug and 1" drain plug. xiv. All groups of cooling equipment shall operate in parallel from the same power source and must be capable of isolating and de-energizing in their individual groups..
