Nema 17 42mm Precision Planetary Gear Motor – Direct Coupling Type Stepper Motor Gearbox 3:1 5:1 10:1 20:1 50:1 70:1

Product Overview

The Nema 17 planetary gearbox is a compact, high-rigidity direct-coupling planetary gearbox with motor structure. Designed for precision control systems, this Precision Planetary Stepper Motor combines low backlash, high torque, and smooth transmission efficiency. It is ideal for robotic joints, optical instruments, and medical automation where accuracy and reliability matter most.

Technical Specifications

Item	Specification
Step Angle	1.8° ±5%
Number of Phases	2
Phase Voltage	3.27 VDC
Phase Current	1.68 A
Phase Resistance	1.95 Ω ±10% (at 20°C)
Phase Inductance	4.4 mH ±20%
Static Torque	0.45N.m
Insulation Class	Class B
Insulation Resistance	≥100MΩ (500V DC)
Ambient Temperature	-20°C ~ +50°C
Ambient Humidity	15% ~ 95% RH
Motor Weight	Approx. 0.32 kg
Rated Voltage	12–24 VDC
Recommended Driver	2D4020A

Reduction Ratio & Performance Table

Reduction Ratio	Reducer Series	Gear Box Length (L)	Efficiency %	Backlash (Arcmin)	Rated Load(N.m)
3	1	40	96	<15	8
4	1	40	96	<15	9
5	1	40	96	<15	9
10	1	40	96	<15	5
12	2	51	94	<20	10
16	2	51	94	<20	10
20	2	51	94	<20	10
25	2	51	94	<20	10
35	2	51	94	<20	10
40	2	51	94	<20	10
50	2	51	94	<20	10
70	2	51	94	<20	10
100	2	51	94	<20	10

Wiring Diagram

The following wiring diagram and table show the standard coil configuration for this planetary stepper motor:

Excitation sequence (CW direction):
STEP   A+   B+   A-   B-
  1     +    +    -   -
  2     -    +    +   -
  3     -    -    +   +
  4     +    -    -   +

Wire Color	Signal	Description
Black (BLK)	A+	Phase A positive
Green (GRN)	A-	Phase A negative
Red (RED)	B+	Phase B positive
Blue (BLU)	B-	Phase B negative

FAQ – Planetary Gear Motor Technical Insights

Q1: What is the most professional English term for “Planetary Gearbox”?

The correct technical term is Planetary Gearbox or Planetary Gearhead.
A “Planetary” gearbox refers to its unique motion structure formed by a sun gear, multiple planet gears, and a ring gear.
“Gearhead” is often used for compact, integrated gear units mounted directly to a motor.

Q2: What is “Backlash,” and why is it important?

Backlash is the small rotational play between the input and output shafts, typically measured in arc-minutes.
Low or zero backlash is critical for precision planetary gear motors used in robotics and CNC applications, ensuring repeatable accuracy and high system responsiveness.

Q3: What does “Direct-Connect Planetary Gearhead” mean?

This term describes an Integrated Planetary Gearbox that is directly coupled to the motor shaft without a separate coupling.
It enhances rigidity, torque density, and alignment accuracy, ideal for compact Integrated Stepper Motor assemblies.

Q4: What is Rated Torque?

Rated Torque defines the continuous torque a speed reducer gearbox can safely transmit over its service life.
Ensuring your load torque is within this limit is vital to guarantee long-term performance and reliability.

Q5: What are the key advantages of Planetary Gear Motors?

Planetary gear motors offer high power density, superior torsional stiffness, and smooth motion transmission.
They deliver compact design, high torque output, and low noise, making them ideal for automation, aerospace, and servo stepper systems.

Applications

• Robotics and automation systems
• Medical instruments and lab automation
• Optical positioning devices
• Industrial automation with planetary gearbox with motor
• 3D printers and precision motion platforms

Download Datasheet

Download the full specification sheet for detailed parameters, wiring guide, and performance curves.

📄 Download PDF Datasheet

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