Editing Stepper motor (section)

==Ratings and specifications==
Stepper motors' nameplates typically give only the winding current and occasionally the voltage and winding resistance. The rated [[voltage]] will produce the rated winding current at DC: but this is mostly a meaningless rating, as all modern drivers are current limiting and the drive voltages greatly exceed the motor rated voltage.

Datasheets from the manufacturer often indicate Inductance. Back-EMF is equally relevant, but seldom listed (it is straightforward to measure with an oscilloscope). These figures can be helpful for more in-depth electronics design, when deviating from standard supply voltages, adapting third party driver electronics, or gaining insight when choosing between motor models with otherwise similar size, voltage, and torque specifications.

A stepper's low-speed torque will vary directly with current. How quickly the torque falls off at faster speeds depends on the winding inductance and the drive circuitry it is attached to, especially the driving voltage.

Steppers should be sized according to published [[torque curve]], which is specified by the manufacturer at particular drive voltages or using their own drive circuitry. Dips in the torque curve suggest possible resonances, whose impact on the application should be understood by designers.

Step motors adapted to harsh environments are often referred to as [[IP65]] rated.<ref>More on what is an IP65 step motor: http://www.applied-motion.com/videos/intro-amps-ip65-rated-motors-motordrives</ref>

=== NEMA stepper motors ===
The US [[National Electrical Manufacturers Association]] (NEMA) standardises various dimensions, marking and other aspects of stepper motors, in NEMA standard (NEMA [https://www.nema.org/standards/view/motion-position-control-motors-controls-and-feedback-devices ICS 16-2001]).<ref>{{Cite web | title=CH0-2 | url=http://www.cncitalia.net/file/pdf/nemastandard.pdf | access-date=2024-12-16 | website=www.cncitalia.net}}</ref> NEMA stepper motors are labeled by faceplate size, NEMA 17 being a stepper motor with a {{convert|1.7|x|1.7|in|mm}} faceplate and dimensions given in inches. The standard also lists motors with faceplate dimensions given in metric units. These motors are typically referred with NEMA DD, where DD is the diameter of the faceplate in inches multiplied by 10 (e.g., NEMA 17 has a diameter of 1.7 inches). There are further specifiers to describe stepper motors, and such details may be found in the ICS 16-2001 standard.