Severe Duty Motors - SD661

General Description

Built in compliance with the requirements of API661 standard, by incorporating regreasable roller bearings and cast iron end caps on frames 210-360, these motors are ideal for use for heavy belt driven air cooled heat exchangers applications in the petrochemical, energy and other similar industries.

Performance Specification


HP Range

5 - 75

Frame Size



Cast Iron


NEMA Premium ®




Service Factor



Class F

Temperature Rise

Class B @ 1.0SF,

Class F @ 1.15SF

Conduit Box

Cast Iron

Fan Cover

Cast Iron

Cooling Fan

Bi-directional - polypropylene


Die Cast Aluminum


0.06 IPS

Inverter Duty

VT 20:1

CT  4:1


A full cast iron construction for exceptional structural integrity, zinc plated corrosion resistance hardware, stainless steel-embossed letters and numbers nameplate, drains at the lowest point of both ends, and ingress protection IP56, for a long service life in the most harsh and demanding environments. Their suitability for horizontal, shaft up, shaft down applications, an oversize and 90º rotatable cast iron conduit box, dual drill foot mounting holes and automatic relief fittings makes these motors the perfect fit every air cooling heat exchanger application possible.


Regreasable, oversized single shielded roller bearings on the drive end with cast iron inner caps for high mechanical performance in belted applications; non drive end is provided with oversized ball bearings. Alemite grease inlet fittings and automatic grease relief fittings for ease of routine maintenance. High water/contaminant ingress protection IP56, that includes Inpro/ Seal® bearing isolators as standard on bearing housings at both ends of the motor.


SD661 severe duty TEFC motors are available in NEMA Premium® efficiency in a 5-75HP range (frame size 184T- 365T). Its design exceeds the IEEE Std, 841TM -2009 standards for high performance, including features like Inpro/ Seal® VBXX bearing isolators on the DE and ODE, 0.06 IPS vibration / 0.005” foot flatness and twice frequency line vibration limits.

Hazardous locations

CSA certified for Class I, Division 2, temperature code T3 for direct on line and variable speed drive operation with an up to 4:1 speed ratio in a constant torque and 20:1 on a variable torque application. Also suitable for Class I, Division 2 temperature code T3 on request.