--- title: U.S. MOTORS and AEGIS Shaft Grounding description: Nidec's U.S. MOTORS brand offers several lines of Inverter Duty motors with AEGIS Shaft Grounding to protect against electrical bearing damage. image: https://blog.est-aegis.com/hubfs/World%20Motor%20Hostile%20Inverter.png --- [![Electro Static Technology](https://blog.est-aegis.com/hubfs/raw_assets/public/public/images/electro-static-technology.svg "Electro Static Technology")](https://www.est-aegis.com/) [![Aegis](https://blog.est-aegis.com/hubfs/raw_assets/public/public/images/Aegis.svg "Aegis")](https://www.est-aegis.com/) - [+1 866-738-1857](tel:+1%20866-738-1857) - [Products](https://www.est-aegis.com/products/) - [AEGIS® SGR – for motors under 500 HP/375 kW](https://www.est-aegis.com/product/sgr/) - [AEGIS® uKIT – for common NEMA/IEC frame size](https://www.est-aegis.com/product/sgr-ukit/) - [AEGIS® RPPR – for reactor recirculating pumps](https://www.est-aegis.com/rppr-resources/) - [AEGIS® EV and EVO Rings - for electric vehicles](https://www.est-aegis.com/product/ev-evo-rings/) - [AEGIS® PRO Series – for motors over 300 HP/225 kW](https://www.est-aegis.com/product/pro-series/) - [Shaft Voltage Testing and Accessories](https://www.est-aegis.com/product/mounting-accessories/) - [Online Product Catalog](https://catalog.est-aegis.com/) - [AEGIS® 2-Year Extended Warranty](https://www.est-aegis.com/product/extended-warranty/) - [Applications](https://www.est-aegis.com/applications/) - [Electric Vehicle Solutions](https://www.est-aegis.com/applications/electric-vehicle-solutions/) - [Food & Beverage](https://www.est-aegis.com/applications/food-beverage/) - [HVAC](https://www.est-aegis.com/applications/hvac/) - [Industrial & Chemical](https://www.est-aegis.com/applications/industrial-chemical/) - [Other Industries](https://www.est-aegis.com/applications/other-industries/) - [Power Generation & Renewable Energy](https://www.est-aegis.com/applications/power-generation-renewable-energy/) - [Transportation](https://www.est-aegis.com/applications/transportation/) - [Water Treatment](https://www.est-aegis.com/applications/water-treatment/) - [Bearing Protection](https://www.est-aegis.com/bearing-protection/) - [Shaft Voltage & Bearing Currents](https://www.est-aegis.com/bearing-protection/shaft-voltage-and-bearing-currents/) - [Fluting & Bearing Inspection](https://www.est-aegis.com/bearing-protection/fluting-and-bearing-inspection/) - [Best Practices & Installation](https://www.est-aegis.com/bearing-protection/best-practices-and-installation/) - [Resources](https://www.est-aegis.com/resources/) - [AEGIS® Bearing Protection Handbook](https://www.est-aegis.com/resources/handbook/) - [IEEE-841, Hazardous Locations, & AEGIS®](https://info.est-aegis.com/technical-codes-and-ieee-841-standards) - [Recorded Webinars Library](https://www.est-aegis.com/resources/recorded-webinars/) - [Installation Instructions](https://www.est-aegis.com/resources/installation-instructions/) - [Videos](https://www.est-aegis.com/resources/videos/) - [Technical Papers](https://www.est-aegis.com/resources/technical-papers/) - [Case Studies](https://www.est-aegis.com/resources/case-studies/) - [Specifying AEGIS®](https://www.est-aegis.com/resources/specifying-aegis/) - [Request Training](https://www.est-aegis.com/resources/training/) - [Product Sheets](https://www.est-aegis.com/resources/product-sheets/) - [About](https://www.est-aegis.com/about/) - [News](https://blog.est-aegis.com/) - [Tradeshows](https://www.est-aegis.com/about/tradeshows/) - [Blog](https://blog.est-aegis.com/) - [Where to Buy](https://www.est-aegis.com/where-to-buy/) - [Distributors](https://www.est-aegis.com/where-to-buy/distributors?type=Distributor) - [Trained Installers](https://www.est-aegis.com/where-to-buy/installers?type=Installer) - [Explosion Proof Installers](https://www.est-aegis.com/where-to-buy/installers?type=Explosion%20Proof%20Installer) - [Motors & Seals with AEGIS® Installed](https://www.est-aegis.com/where-to-buy/oems-with-aegis/) [Contact Us](https://www.est-aegis.com/contact/) - [+1 866-738-1857](tel:+1%20866-738-1857) # U.S. MOTORS with AEGIS [Home](https://www.est-aegis.com/) » [Blog](https://blog.est-aegis.com/) » U.S. MOTORS with AEGIS [AEGIS](https://blog.est-aegis.com/author/estaegis) Aug 9, 2022 ## 110+ Years of Innovation The United States Electrical Manufacturing Company began ![old-vhs](https://blog.est-aegis.com/hs-fs/hubfs/old-vhs.png?width=300&name=old-vhs.png)making electric motors in 1908.  A lot has changed in the past 114 years, but U.S. MOTORS' relentless drive for innovation is the same. In 1922, they invented the vertical HOLLOSHAFT® motor that has revolutionized pumping.  In 1925 they were the first to make ball bearings standard in all motors.  In 1932 they invented the VARIDRIVE® motor, comprising a constant speed motor and variable speed transmission.  [And so on](https://acim.nidec.com/motors/usmotors/about-us/history)... U.S. MOTORS continues to innovate with its Inverter Duty and Vector Duty lines of motors.  These motors include robust insulation to protect the windings from damage by VFD control.  They also include AEGIS® Shaft Grounding Rings to protect the bearings from shaft voltage discharge. The full range of U.S. MOTORS with AEGIS rings standard is: - HOLLOSHAFT Inverter Duty: - WPI 10:1 variable torque: 254-447 frame - TEFC 10:1 variable torque: 182-449 frame - UNIMOUNT® Inverter Duty: 143-256 frame - ![World Motor Hostile Inverter](https://blog.est-aegis.com/hs-fs/hubfs/World%20Motor%20Hostile%20Inverter.png?width=300&name=World%20Motor%20Hostile%20Inverter.png)HOSTILE DUTY® Definite Purpose Inverter Duty: 182-447 frame - World Motor HOSTILE DUTY Inverter Duty: 143-447 frame - ACCU-Torq® HOSTILE DUTY TENV Vector Duty: 182-449 frame - ODP Inverter Duty: 143-447 frame - VariTough® Inverter Duty Motors, "VG" part number suffix AEGIS Rings offer a [2-year extended warranty](https://www.est-aegis.com/product/extended-warranty/) against bearing fluting damage.  No other shaft grounding device manufacturer offers a warranty like this. [![2-Year Extended Warranty](https://no-cache.hubspot.com/cta/default/20974229/3b258d08-3058-4c7f-a866-2991b627f2e0.png)](https://cta-redirect.hubspot.com/cta/redirect/20974229/3b258d08-3058-4c7f-a866-2991b627f2e0) To learn more about AEGIS shaft grounding and best practices for electrical bearing protection, [sign up for a training](https://www.est-aegis.com/resources/training/).  We offer monthly live training webinars, and we can also visit your facility to review your exact application. [![Sign Up For Training](https://no-cache.hubspot.com/cta/default/20974229/69dd56c7-bbd1-4ad0-ae5c-29de322039f0.png)](https://cta-redirect.hubspot.com/cta/redirect/20974229/69dd56c7-bbd1-4ad0-ae5c-29de322039f0) [Vertical Motors](https://blog.est-aegis.com/tag/vertical-motors), [U.S. Motors](https://blog.est-aegis.com/tag/u-s-motors), [Nidec Motors](https://blog.est-aegis.com/tag/nidec-motors) ### Subscribe To Our Blog ## Read On ### [Nidec Unimount Motors with AEGIS](https://blog.est-aegis.com/nidec-unimount-motors-with-aegis?hsLang=en-us) Nidec's [U.S. Motors](https://acim.nidec.com/motors/usmotors/) is one of the oldest and most respected brands of electric motor. They may be... ### [Marathon Motors with Bearing Current Protection](https://blog.est-aegis.com/marathon-motors-with-bearing-current-protection?hsLang=en-us) In its long history, Marathon Motors has seen some changes. When they produced their first washing... ### [U.S. Motors Inverter Duty World Motors Now Have AEGIS Inside](https://blog.est-aegis.com/u-s-motors-inverter-duty-world-motors-now-have-aegis-inside?hsLang=en-us) U.S. Motors' World Motor® line of severe duty motors includes some of the toughest motors out... 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