NEMA is "National Electrical Manufacturers Association" and their standard for motor mounts is commonly used in the industry to ensure that replacement parts will fit and be readily available, and that motors from different mfgs will be interchangeable. The NEMA number is related to the diameter of the motor times 10. So a NEMA 23 motor is 2.3 inches around or down the side.
|Dimension in Inches (mm)||NEMA Motor Mounting Dimensions|
|NEMA 8||NEMA 11||NEMA 14||NEMA 17||NEMA 23||NEMA 34||NEMA 42|
|Motor Size (DD)||~0.8||~1.1||~1.4||~1.7||~2.3||~3.4||~4.2|
|a: Bolt Hole Distance (square)||0.630 (16)||0.905 (23)||1.024 (26)||1.220 (31)||1.854 (47.14)||2.744 (69.7)||3.500 (88.9)|
|b: Motor Shaft Diameter||0.157 (4)||0.197 (5)||0.197 (5)||0.197 (5)||0.250 (6.35)||0.375 (9.5)||0.625 (16)|
|c: Motor Shaft Length (max)||0.945||0.810||1.250||1.380|
|d: Pilot Diameter||0.590 (15)||0.866 (22)||0.866 (22)||0.866 (22)||1.500 (38.1)||2.875 (73)||2.186|
|e: Pilot Depth (max)||0.059 (1.5)||0.079 (2)||0.079 (2)||0.079 (2)||0.062 (1.6)||0.062 (1.6)||0.062 (1.6)|
|f: Bolt Hole Circle Diameter||1.725||2.625||3.875||4.950|
|g: Bolt Hole Size||0.118 (3)||0.157 (4)||0.157 (4)||4-40 UNC||0.195 (5)||0.218 (5.5)||0.281|
|Thanks to Neil (PICDude) for these excellent pictures!|
The primary NEMA number specifies the position and size of the mounting face
as shown in the table above. The full NEMA standard also describes other
features of the motor. The full NEMA description of a stepper motor is written
NEMA DDMMLLL-CCCIVVVSSSW, where:
For example: a 3.4" diameter stepper motor with a flange that is 1.6 inches long, has a phase current of 1.2 Amps, class B insulation, 5.3 phase voltage, 200 steps per revolution, and 8 wires is: NEMA 34D016-012B053200F
I have a query. I have a stepper motor square of 4.2 inches and length of approx. 6 inches. It has 4 (Four) wires, bipolar. apart from this I have no other information. I may be able to measure the coil resistance at the most. how do i determine the working voltage, current and watts? I need to choose a suitable drive for the motor.James Newton of MassMind replies: See wiring to work out which wire is which. As to the rest, I really don't know.+
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