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Technical Specifications
Last Updated: 2026-09-16
Weight
Dimensions
Torque
Speed
Current
Temp
Wire
| Identity | |
| Brand |  |
| Product Number | 37990S |
| Category | Hobby |
| Discontinued | Yes |
| Performance | |
| Torque |
7.4V
611.00 oz-in
44.00 kg-cm
4.3 N-m
6.0V
500.00 oz-in
36.00 kg-cm
3.5 N-m
Top 10%
|
| Speed |
7.4V
0.17 sec/60°
352.9 deg/s
58.8 RPM
6.0V
0.21 sec/60°
285.7 deg/s
47.6 RPM
Bottom 10%
|
| Running Current |
7.4V
0.480 A
480 mA
6.0V
0.400 A
400 mA
Below Average
|
| Stall Current | 8.1–9.9 A8100–9900 mABottom 10% |
| Physical | |
| Weight | 2.79 oz79.0 gBelow Average |
| Dimensions |
L 1.724 in W 0.882 in H 1.575 in L 43.8 mm W 22.4 mm H 40.0 mm |
| Case Material | Plastic / Aluminum |
| Drivetrain | |
| Motor Type | Coreless |
| Motor Drive | FET |
| Gears | Titanium |
| Gear Spline/Teeth | 25 T |
| Rotation Mode | Positional |
| Rotation/Support | Dual Bearings |
| Backlash | 0.500° |
| Control & Signal | |
| Modulation | Digital |
| Direction | Clockwise |
| Rotational Range | 90° |
| Mechanical Limit | 300° |
| Pulse Width | 1050-1950 µs |
| Neutral Position | 1500 µs |
| Dead Band | 2 µs |
| Angle Sensor | Magnetic Encoder |
| Control System | PWM |
| Programmable | Yes |
| Electrical & Environment | |
| Operating Voltage | 6–7.4 V |
| Power Source | 2S LiPo |
| Temperature | -20–60 °C-4–140 °F |
| Water Rating | IP54 |
| Idle Current | 0.023 A23 mA |
| Connectivity | |
| Connector | JR (Universal) |
| Wire Length | 300 mm11.81 in |
Disclaimer: Most data is sourced from the manufacturer. Some data is sourced from our loyal community and with the help of AI. We aim for accuracy but are not responsible for inaccurate information.
Class Comparison
| Torque | Top 10% Stronger than 92% of 1060 Digital Standard servos at 6.0V |
| Speed | Bottom 10% Faster than 8% of 1045 Digital Standard servos at 6.0V |
| Weight | Below Average Lighter than 14% of 1880 Digital Standard servos |
| Running Current | Below Average Lower draw than 24% of 226 Digital Standard servos at 6.0V |
| Stall Current | Bottom 10% Lower draw than 3% of 570 Digital Standard servos |
Performance Analysis
| Shaft Power | 4.40–6.65 W |
| Power Density | 2.775 W/in³ More power-dense than 57% of 1768 Digital Standard servos |
| Torque Density | 6.3291 oz-in/g Stronger than 90% of 1053 Digital Standard servos |
| Torque-to-Volume Ratio | 208.78 oz-in/in³ Denser torque than 85% of 1058 Digital Standard servos |
| Speed-to-Weight | 0.06028 (1/sec·g) Faster than 2% of 1038 Digital Standard servos |
| Speed-Torque Trade-off | 105.01 Better balanced than 97% of 1034 Digital Standard servos |
| Current-per-Torque Ratio | 0.0198 A/oz-in More efficient than 31% of 331 Digital Standard servos |
| Idle-to-Running Current Ratio | 0.058 Lower idle draw than 46% of 167 Digital Standard servos |
| No-Load vs Stall Current Spread | 24.75 Narrower current spread than 41% of 179 Digital Standard servos |
| Torque Gain per Volt | 15.86%/V More voltage-responsive (torque) than 51% of 873 Digital Standard servos |
| Speed Gain per Volt | 16.80%/V More voltage-responsive (speed) than 60% of 874 Digital Standard servos |
| Voltage Range Width | 1.4 V Wider voltage range than 37% of 1560 Digital Standard servos |
| Backlash-to-Range Ratio | 0.00556 Tighter backlash than 16% of 52 Digital Standard servos |
| Dead-Band-to-Pulse-Width Ratio | 0.0022 Finer dead band than 12% of 504 Digital Standard servos |
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