I had the same identical steppers on all axis's, 3V 3A. 2 on the X. single on the Y and a obviously a single on the Z.... The Z locked up because of a bad bearing, so I bought a replacement thats has a bit more torque, but still 3V 3A. The 3 original steppers barely produce any heat sitting idle, but the new one wow, not hot enough to burn ya but deffinetely a significant difference. Im driving them with a Hobby CNC Pro 4 axis. Guess my question is do the new steppers just run hotter?