H3X Technologies

H3X Technologies is a Denver, Colorado-based developer of ultra-high power density integrated electric motor and drive systems, claiming world-record continuous power density of 9.5–12 kW/kg in its HPDM-250 axial flux motor (250 kW continuous output). The company's innovation lies in combining the motor, motor controller, and thermal management into a single integrated unit — eliminating the cable harness and connector overhead between separately packaged components and enabling dramatic size and weight reductions compared to conventional motor + inverter combinations.

This power density is critical for electric aviation: eVTOL (electric vertical takeoff and landing) aircraft, electric regional commuter planes, and electric propulsion systems for hybrid aircraft all require motors with the highest possible power-to-weight ratios to achieve practical flight performance. H3X's technology also has relevance to space: high power density motor drives are used in spacecraft attitude control reaction wheels, electric propulsion gimbal actuators, and pump-fed electric propulsion systems.

Y Combinator W21 graduate, H3X has raised over $20M in funding from aerospace-focused investors. The company competes with MagniX and Rolls-Royce Electrical in the electrification of aviation market while pursuing defense and space applications of its motor drive technology.