Turnabot N20 Planetary gearmotor
They’re here. The Turnabot N20 Planetary Gearmotors deliver exceptional durability and torque in a compact, proven form factor, making them the go-to choice for builders who want planetary strength without excess bulk. Superior to spur gear motors, they’re built around a true 12mm all-metal planetary gearbox, with weights starting at 15.2g—designed to survive combat robotics abuse while offering an excellent balance of power, size, and reliability. Ideal for drive systems where strength and consistency matter most.
$19.00
28 in stock (can be backordered)
Why a Planetary Gearmotor?
In combat robotics, drive motors are exposed to repeated shock loads, sudden reversals, and side impacts that quickly reveal the limits of traditional spur gearboxes. Planetary gearboxes distribute load across multiple gears and through a rigid carrier and ring, significantly improving impact resistance while increasing torque capacity within the same diameter envelope.
The Turnabot N20 Planetary Gearmotors are built around a true 12mm all-metal planetary gearbox, offering a substantial durability upgrade over spur gear motors of similar size. This design helps resist shaft bending, gear tooth shear, and retention failures that commonly end matches early in competitive weight classes.
The Most Versatile Planetary Size
The N20 planetary format is widely regarded as the best all-around size for small combat robots, offering a strong balance of torque, speed, and thermal capacity. With weights starting at 15.2g, N20 planetaries provide significantly more durability and torque margin than smaller motors while remaining compact enough for efficient chassis layouts.
This makes the N20 planetary gearmotor an excellent choice for primary drive systems in antweight and beetleweight robots, as well as any application where consistent performance over a full match is critical.
Output Shaft and Wheel Retention
Each N20 planetary gearmotor features a robust output shaft with a machined retention notch and ships with a circlip for secure wheel retention. This system dramatically improves resistance to wheel loss under weapon hits and wall impacts, a common failure mode for spur gearmotors and smooth-shaft designs.
Speed, Torque, and Electrical Considerations
The Turnabot N20 Planetary Gearmotors are available in multiple speed options to support a wide range of drive styles, from controlled pushing bots to faster, more aggressive configurations. Published RPM values should be considered typical measured performance under standard conditions; engraved motor markings may not reflect final output speed once installed in a planetary gearbox or operated at different voltages.
Manufacturer testing and recommendations frequently reference Malenki Standard and Malenki HV brushed ESCs, which are known to work well with these motors. Other brushed ESCs may also be used, provided their voltage capability and current handling match the selected motor variant and battery configuration. Always verify ESC and battery specifications when designing your drivetrain.
Features
- N20 motor plus planetary drivetrain: Combines the widely used N20 motor size with a true all-metal planetary gearbox for dramatically improved durability and torque.
- All-metal 12mm planetary gearbox: Planetary load sharing improves shock resistance, helping the drivetrain survive weapon hits, wall impacts, and repeated reversals.
- Excellent balance of size and power: Weights start at 15.2g, offering a strong middle ground between ultralight N10 motors and larger N30 options.
- Compact, proven form factor: Ideal for primary drive systems in small combat robots where reliability and consistency matter.
- Multiple speed options: Available in a range of RPM variants to support controlled pushers or faster, more aggressive drive setups.
- Robust output shaft with retention groove: Designed to support secure wheel retention under impact while remaining compatible with common hub styles.
Specifications
Motor Specifications
| Motor Specifications (TB N20) | Value |
| Gearbox Diameter | 12mm |
| Output Shaft Diameter | 3mm |
| Output Shaft Length | 16mm |
| Overall Length | ~39mm |
| Mounting Holes | 2× M2 |
| Mounting Hole Spacing | 8.5mm |
| Wheel Retention Feature | Retention groove (circlip included) |
| Typical Weight | Starts at 15.2g |
Planetary Motor Family Comparison
| TB N10 | TB N20 | TB N30 2S | TB N30 3S | |
| Weight (g) | 13.8 | 15.2 | 17.8 | 17.8 |
| 2S Speed (RPM) | 1540 | 1300 | 1250 | 1440 |
| 2S Current (A) | 1.1 | 2.1 | 3.1 | 2.2 |
| 2S Torque (g·cm) | 769 | 1385 | 0 | |
| 3S Speed (RPM) | 2310 | 1950 | 1875 | 2160 |
| 3S Current (A) | 1.65 | 3.15 | 4.65 | 3.3 |
| 3S Torque (g·cm) | 1154 | 2077 | 0 | |
| Recommended ESC | Malenki Standard or equivalent brushed ESC | Malenki Standard or Malenki HV, or equivalent | Malenki HV or equivalent high-current ESC | Malenki HV or equivalent high-current ESC |
| Recommended Battery | 2S–3S LiPo (application dependent) | 2S–3S LiPo (application dependent) | 2S LiPo recommended | 3S LiPo recommended |
Frequently Asked Questions
Why doesn’t the RPM engraved on the motor match the RPM listed in the specs?
The RPM values listed in the specifications represent typical measured output speed under real operating conditions. Engraved markings on the motor can reflect nominal ratings, different test voltages, or manufacturer labeling conventions and should not be relied on as final output speed once installed in a planetary gearbox. Always use the published specifications when designing your drivetrain.
Do I have to use a Malenki ESC with these motors?
No. The manufacturer’s recommendations reference Malenki Standard and Malenki HV ESCs because they are known, tested combinations. Other brushed ESCs can be used as long as their voltage rating and current capability are appropriate for the selected motor variant and battery configuration. Always verify ESC specifications before installation.
Can I run the N20 planetary motors on both 2S and 3S?
Yes. N20 planetary gearmotors are commonly used on both 2S and 3S LiPo batteries depending on the selected motor variant and application. Higher voltage increases speed and current draw, so ensure your ESC and battery are rated accordingly.
Do I have to use the included circlip for wheel retention?
No. The retention groove and included circlip provide a secure option for wheel retention under impact, but many builders choose to use set-screw or clamping hubs instead. The retention groove does not prevent the use of common hub styles.
What tools are required to install or remove the circlip?
Circlips are typically installed and removed using small snap-ring pliers or fine needle-nose pliers. Care should be taken during installation and removal to avoid scratching the shaft or generating metal debris. If you prefer not to work with circlips, compatible set-screw or clamping hubs can be used instead.
Will my existing N20 motor mounts fit these gearmotors?
The gearbox diameter follows the standard 12mm planetary format, but overall length and shaft features differ from spur-gear N20 motors. Always verify dimensions against your chassis or CAD before final installation, especially in tight layouts.
Are these motors only for combat robotics?
While designed to survive the shock loads and abuse common in combat robotics, these motors are also well-suited for any application requiring compact size, higher torque capacity, and improved durability compared to traditional spur gearmotors.