Cardinal Pumps” offers a line of pumps designed to meet the requirements of transformer-oil applications. To meet the extreme temperatures common to such environments, the pumps are rated for continuous-duty operating temperature ranges from –40 C (–40 F) to 100 C (212 F). The pumps also have other special features for transformer-oil applications, such as the capability to permit thermo-siphon flow when the pump is not operating, allowing natural convection even when the pump is completely shut off. For long life in the field, all pumps offer rugged split-casing design with heavy-duty class 30 cast iron for the pump casting, motor enclosures, impellers, and volutes. Large thrust face sleeve bearings also extend life, minimize wear, and reduce maintenance. Cardinal offers three bearing types: standard sleeve bearing, the Harley sleeve bearing, and the Harley sleeve bearing with TecSonics bearing wear monitoring. All Cardinal pump and motor units are subjected to pressure tests to 50 PSIG to ensure the integrity of the complete unit. Motor windings are all tested for 60 seconds at 2x voltage + 1000 to ensure electrical integrity and continuity, with winding resistance taken both before and after the pump is built. Pumps are also meggar tested to ensure the integrity of the insulation.