Because this is a "15mm" short-body NEMA 17, its holding torque is roughly half that of a standard 40mm/48mm long NEMA 17 (which usually have ~0.4 to 0.5 N·m of torque).

A: High resistance limits current naturally. This motor was designed before cheap, efficient chopper drivers existed. It runs directly off a 26V regulated supply without needing a current-limiting driver.

When purchasing a BJ42D15 26V10 stepper motor, request a Certificate of Conformance (CoC) or ask the supplier to verify via multimeter:

If you measure 1.8 Ohms, you have received a standard 3D printer motor – DO NOT use it with 26V.