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Enter your robot mass, wheel size, speed, grade, and 12 V motor data. The tool returns a ratio window, startup-current warning, and next action before the report explains the evidence and trade-offs.
| Source | How it is used | Boundary |
|---|---|---|
| Pololu 37D 12V Metal Gearmotors Checked 2026-06-06 | Anchors the 12 V 37D family as a common robot gearmotor option with 5.5 A stall-current class and 200 mA typical free-run current. | Catalog current is model-family data; final current margin must use the exact selected motor and gearbox. |
| Pololu 37D Metal Gearmotors category Checked 2026-06-06 | Provides the 6.3:1 to 150:1 37D ratio envelope plus continuous and instantaneous load warnings. | Pololu warns listed stall values are extrapolated and thermal damage can occur quickly near stall. |
| REV Robotics HD Hex Motor documentation Checked 2026-06-06 | Provides a 12 V robotics motor benchmark: 6000 rpm free speed, 8.5 A stall current, 0.105 Nm stall torque, and 15 W max output power. | Bare motor numbers require gearbox selection before wheel torque can be judged. |
| REV UltraPlanetary Gearbox Kit Checked 2026-06-06 | Confirms a common modular robotics gearbox reduction range from nominally 3:1 to 60:1. | Competition-style modular gearboxes are useful references but not always industrial-duty replacements. |
| REV DUO motor basics Checked 2026-06-06 | Defines stall torque/current, explains why free speed falls under load, and warns that stall heat can damage a motor. | General motor guidance; the exact safe duty point still comes from the selected motor supplier. |
| FIRST Robotics robot battery basics Checked 2026-06-06 | Supports the battery-sag warning: 12 V robot batteries drop voltage under load and high-current use changes usable capacity. | FRC uses a specific 12 V 18 Ah SLA battery; transfer the principle, not the exact pack rating, to custom robots. |
| ANSI/CAN/UL/ULC 2271 Ed. 2 Checked 2026-06-06 | Clarifies that light electric vehicle battery safety standards cover energy storage assemblies, not motor performance or reliability. | Only relevant when the robot product falls into a light electric vehicle or similar battery safety scope. |
| IEC 60204-1 wiring guidance summary Checked 2026-06-06 | Adds a wiring check: cable voltage drop from supply to load should not exceed 5% of nominal voltage in normal operation. | Use the applicable regional standard and electrical engineer sign-off for regulated machinery. |
| DFRobot mobile robot torque calculation tutorial Checked 2026-06-06 | Supports the force-to-wheel-torque workflow used in the calculator. | The page supports screening math, not final validation under shock, heat, and battery sag. |
The table separates source-backed decisions from assumptions that still need supplier data or bench testing. Items marked as unavailable should stay待确认 until the exact motor, controller, harness, and battery are tested.
| Conclusion | Public signal | Decision use | Known limitation |
|---|---|---|---|
| A 12 V label is not a fit decision. | REV defines operating voltage, free speed, stall torque, and stall current as interrelated motor metrics; Pololu publishes the same 12 V family across ratios from 6.3:1 to 150:1. | Screen voltage, no-load speed, gearbox ratio, torque, current, and battery behavior together before asking for RFQ pricing. | Public category pages rarely publish a complete thermal map, so sustained duty must be tested or requested. |
| Stall numbers are emergency boundaries, not repeated-use targets. | REV states stall is zero rpm at full stall current and warns heat can eventually cause failure; Pololu notes stalling is likely to damage the gearmotor. | Treat startup-current estimates as a warning trigger and validate current clipping with a real launch log. | The calculator estimates startup current from available motor inputs; it does not model winding temperature rise. |
| Gear ratio availability is discontinuous. | REV UltraPlanetary references nominal 3:1 to 60:1 configurations; Pololu 37D 12 V options list 6.3:1 to 150:1 ratios. | Use the result ratio window to find catalog ratios that actually exist, then check load limits and mounting. | A mathematically perfect ratio can still fail due to shaft support, gearbox load rating, or packaging. |
| Battery sag and cable drop can invalidate an otherwise correct motor calculation. | FIRST documentation notes 12 V battery voltage drops under load; IEC 60204-1 guidance summaries call out voltage drop limits in wiring. | For negative or tight current margin, compare 24 V architecture, larger conductors, shorter cable runs, and softer acceleration ramps. | Pack chemistry, connector resistance, and harness routing are project-specific and must be measured. |
| Battery safety evidence is separate from drivetrain performance evidence. | UL 2271 covers light electric vehicle battery energy storage assemblies and explicitly does not evaluate device performance or reliability. | Ask for both battery safety/compliance evidence and motor torque-speed-current evidence; one does not replace the other. | Whether UL 2271 is applicable depends on the finished product category and sales region. |
| Option | Ratio signal | Strength | Risk | Best for |
|---|---|---|---|---|
| 12 V brushed gearmotor | 20:1 to 150:1 common screen | Lowest control complexity and broad catalog availability | Brush wear, heat near stall, current spikes | Education bots, indoor AMRs, cost-sensitive prototypes |
| 12 V BLDC gearmotor | 10:1 to 80:1 typical short list | Higher efficiency and better sustained-duty potential | Driver tuning, EMI, higher integration effort | Long runtime platforms and speed-controlled mobile robots |
| Bare 12 V motor + modular gearbox | 3:1 to 60:1 reference range | Fast iteration and easy ratio swaps | Mounting stiffness and non-industrial duty uncertainty | FTC-style robots, lab rigs, early drivetrain experiments |
| Move to 24 V architecture | Same mechanical math, lower current for comparable power | Lower current stress in wiring/controller for higher power | Battery, driver, safety, and charger stack changes | Heavier duty cycle or current-limited 12 V prototypes |
| Check | Pass signal | Fail signal | Owner |
|---|---|---|---|
| Launch-current log | Peak current remains below controller limit with margin during repeated starts and direction changes. | Brownout, controller foldback, fuse heating, or current peaks above the configured limit. | Controls engineer |
| Loaded speed test | Measured speed at payload and floor condition lands inside the target band after battery sag. | No-load rpm looked correct, but loaded wheel rpm falls below the mission requirement. | Mechanical and controls |
| Thermal soak | Motor, gearbox, controller, and wiring temperatures stabilize across the expected duty block. | Temperature keeps rising, gear grease odor appears, or controller derates during the run. | Test engineer |
| Harness voltage drop | Voltage at the controller/motor remains inside the allowed design window at normal load. | Cable length, connector resistance, or undersized conductors consume the current margin. | Electrical engineer |
| Supplier evidence review | Supplier provides original curves, duty rating, efficiency assumption, gearbox load limit, and test date. | Only headline voltage, speed, and marketing torque are available. | Procurement |