P841/D4, Jul 2008 is a technical standard for cooled, totally enclosed fan-cooled (TEFC) squirrel cage induction motors up to and including 370 kW (500 hp). It addresses key design and performance considerations for larger motor applications where dependable operation, thermal control, and consistent ratings are important. For power, energy, and industrial users, this standard helps define a clearer basis for specification, evaluation, and procurement of motor equipment.

P841/D4, Jul 2008 overview

P841/D4, Jul 2008 provides a focused framework for TEFC squirrel cage induction motors within a defined power range. In practical terms, it supports the technical comparison of motor designs by helping align expectations for construction, cooling, ratings, and general performance characteristics. As an inactive standard, P841/D4, Jul 2008 remains useful as a reference point for legacy equipment, documentation review, and historical engineering requirements in industrial power applications.

Typical use cases

This standard is commonly relevant when specifying or reviewing medium-to-large induction motors used in pumps, fans, compressors, conveyors, and other driven equipment that benefits from enclosed cooling and rugged construction. It may also be used in plant engineering, maintenance planning, and replacement sourcing where TEFC squirrel cage motors must fit established performance and mounting expectations. In power and industrial settings, it can help support consistent selection across repeated motor installations.

Why this standard matters

For procurement, design control, and equipment verification, P841/D4, Jul 2008 helps reduce uncertainty around motor requirements in the higher power range it covers. A clear standard can improve consistency between suppliers, simplify technical review, and support more reliable testing or acceptance practices. It is especially valuable when matching replacement motors to existing installations, where cooling method, duty expectations, and rating alignment may affect system performance and operating risk.

• TEFC squirrel cage induction motors
• Up to and including 370 kW (500 hp)
• Cooling, rating, and construction reference
• Industrial power and energy applications
• Legacy specification and procurement support