Expanded Scope Electric Motors

THE PRODUCT:

Expanded scope electric motors (ESEMs) are a subset of small motors (0.25 to 3 hp) not covered by DOE’s small electric motor standards. ESEMs include permanent split capacitor (PSC), shaded pole, and split-phase motors, as well as certain types of capacitor-start induction-run (CSIR), capacitor-start capacitor-run (CSCR), and polyphase motors. Typical applications for ESEMs include fans, refrigeration/HVAC compressors, and pumps.

STANDARD:

There are currently no federal standards in effect for ESEMs.

In 2025, DOE issued a final rule for ESEMs with compliance required starting in 2029. The final rule covers several types of currently unregulated motors, setting the first efficiency standards for several motor topologies including both air-over (AO) and non-AO PSC, shaded pole, and split-phase motors. The final rule also sets standards for additional types of capacitor-start induction-run CSIR, CSCR, and polyphase motors that are not covered by the existing standards for small electric motors (e.g., AO and/or enclosed motors).

KEY FACTS:

The efficiency of an ESEM can be improved by switching to more efficient topologies (e.g., from split-phase to CSCR or from shaded pole to PSC) and more generally by minimizing various losses including electrical resistance (I2r) losses, core losses, friction and windage losses, and stray load losses. Losses within a given ESEM topology can be reduced by increasing capacitor size or changing lamination stack characteristics (e.g., electrical steel quality/thickness, design).