Siemens released a severe duty motor, the NEMA Premium SD661, for use in the petrochemical, energy and other similar industries and for specialized use in air- cooled heat exchanger applications. The SD661 motor provides mounting flexibility and application on adjustable speed drives.
The SD661’s full cast iron construction, corrosion resistant hardware, bearing isolators on both ends, IP56 ingress protection and T-drains at the lowest point on both ends provide mechanical integrity for long service life in harsh industrial environments, according to the company. The motor is suitable for horizontal, shaft up or shaft down mounting and is equipped with oversized roller bearings for belted applications. The SD661 features an oversized and 90 degree rotatable cast iron conduit box, dual drill foot mounting holes and automatic grease relief fittings.
The SD661 severe duty TEFC motor is available in 5-75HP range (frame sizes 184T-365T). Its design meets or exceeds the IEEE Std, 841-2009 standard for high performance, with features like Inpro/Seal VBXX bearing isolators on the DE and ODE, 0.06 IPS vibration / 0.005” foot flatness and twice line frequency vibration limits.