China sourcing · 12V demand estimate + buyer guide
12V DC Planetary Gear Motor China
Estimate demand and prepare a China supplier RFQ.
12V OEM demand sizer
Published · Sources checked · By Micro Planetary Motor
Evidence scope: public manufacturer guidance and official reference pages. No factory audit, supplier certification, MPM test dataset or customer outcome is verified here. Example calculations are hypothetical.
Four decisions before you approve a motor
A load estimate is not an approved motor selection
The calculator quantifies demand. Require the exact winding, gear ratio, operating curve and continuous limits before accepting a compact frame.
Evidence & scopeState the duty profile before comparing torque
S2 short-time operation and S3 repeated cycles are different. Supply run time, rest time, starts, ambient temperature and mounting conditions.
Evidence & scopeSpecify holding separately
High ratio and static friction do not guarantee a planetary drive will retain a gravity load. Obtain a rated holding solution and verification plan.
Evidence & scopeCompare noise using the same metric
Specify load, speed, distance, mounting and background noise. Do not compare sound power directly with a single-position sound-pressure reading.
Evidence & scopeCalculation method and sensitivity
At steady speed: ratio = loaded motor RPM / output RPM; P output = T × 2π × RPM / 60; η gearbox = η stage raised to stage count; current = P output / (12 × η motor × η gearbox). Required motor torque is output torque / (ratio × η gearbox).
The stage count is a planning minimum assuming at most 5.5:1 per stage, rounded up. It does not identify a purchasable ratio. Defaults are illustrative and independent of diameter, technology or material. Actual efficiency varies with operating point.
| Decision / input | Known / unknown | Action / verification |
|---|---|---|
| Default planning assumptions | Motor η 68%; stage η 85%; 3 stages; gearbox η 61.4%. | 7.54W shaft output; 18.05W estimated electrical input; 1.50A at 12V. |
| Lower assumed efficiencies | Motor η 55%; stage η 75%; 3 stages; gearbox η 42.2%. | Same 7.54W output requires an estimated 32.49W input / 2.71A. Obtain operating-point data. |
| Supplier-confirmed configuration | Unknown: actual winding, catalog ratio and efficiencies. | Recalculate with confirmed values, then validate loaded and startup conditions. |
Default planning assumptions
- Known / unknown
- Motor η 68%; stage η 85%; 3 stages; gearbox η 61.4%.
- Action / verification
- 7.54W shaft output; 18.05W estimated electrical input; 1.50A at 12V.
Lower assumed efficiencies
- Known / unknown
- Motor η 55%; stage η 75%; 3 stages; gearbox η 42.2%.
- Action / verification
- Same 7.54W output requires an estimated 32.49W input / 2.71A. Obtain operating-point data.
Supplier-confirmed configuration
- Known / unknown
- Unknown: actual winding, catalog ratio and efficiencies.
- Action / verification
- Recalculate with confirmed values, then validate loaded and startup conditions.
Values use 1.2 N·m, 60 output RPM and 5,800 loaded motor RPM. The lower-efficiency example estimates running current only; it is not a worst-case startup or stall bound. No-load losses and controller behavior require measured data.
China supplier evaluation: evidence before labels
Search by capability, then verify the manufacturing site
Send the same specification to each China supplier. Request legal entity, manufacturing address and a configuration-specific quote. This page does not rank regions, certify a supplier tier or infer capability from city names.
| Decision / input | Known / unknown | Action / verification |
|---|---|---|
| Manufacturing identity | A company name or marketplace badge does not show who builds the motor. | Request legal manufacturer identity, production address, subcontracting scope and a dated process walkthrough. |
| Engineering ownership | A catalog drawing may describe a different winding, stage count or shaft. | Ask who controls drawings, revisions, winding records and gear tooling; match the quote to a drawing revision. |
| Quality capability | Certification scope and test coverage are supplier-specific; no supplier ranking is verified here. | Check certificate issuer/site/scope/expiry, calibrated instruments, sample reports and batch traceability. |
| Production repeatability | Hand-built samples may not represent a production line. | Agree pilot quantity, sampling rules, acceptance limits and change notification before the volume order. |
Manufacturing identity
- Known / unknown
- A company name or marketplace badge does not show who builds the motor.
- Action / verification
- Request legal manufacturer identity, production address, subcontracting scope and a dated process walkthrough.
Engineering ownership
- Known / unknown
- A catalog drawing may describe a different winding, stage count or shaft.
- Action / verification
- Ask who controls drawings, revisions, winding records and gear tooling; match the quote to a drawing revision.
Quality capability
- Known / unknown
- Certification scope and test coverage are supplier-specific; no supplier ranking is verified here.
- Action / verification
- Check certificate issuer/site/scope/expiry, calibrated instruments, sample reports and batch traceability.
Production repeatability
- Known / unknown
- Hand-built samples may not represent a production line.
- Action / verification
- Agree pilot quantity, sampling rules, acceptance limits and change notification before the volume order.
Motor and gear architecture: compare the complete drive
| Decision / input | Known / unknown | Action / verification |
|---|---|---|
| Brushed PMDC | Simple commutation and two motor terminals; brush wear needs qualification. | Compare running/starting current, brush construction, driver protection and life under the actual duty. |
| BLDC | Requires electronic commutation; driver, sensor and wiring become part of the drive. | Include controller cost, control interface and thermal behavior; do not assume a guaranteed lifetime. |
| Coreless | Describes rotor construction, not a guarantee of noise, current or brushless operation. | Confirm commutation type and compatible controller; evaluate with the load inertia. |
Brushed PMDC
- Known / unknown
- Simple commutation and two motor terminals; brush wear needs qualification.
- Action / verification
- Compare running/starting current, brush construction, driver protection and life under the actual duty.
BLDC
- Known / unknown
- Requires electronic commutation; driver, sensor and wiring become part of the drive.
- Action / verification
- Include controller cost, control interface and thermal behavior; do not assume a guaranteed lifetime.
Coreless
- Known / unknown
- Describes rotor construction, not a guarantee of noise, current or brushless operation.
- Action / verification
- Confirm commutation type and compatible controller; evaluate with the load inertia.
More stages change efficiency; they do not certify holding
With the illustrative 85% per stage assumption, three stages give 61.4% gearbox efficiency and four give 52.2%. Real tooth counts, lubrication, temperature and load change these figures. Do not infer reverse efficiency or load holding from forward efficiency.
Manufacturer guidance distinguishes friction-dependent holding from intrinsic self-locking. Confirm the complete drive behavior and specify an independently rated holding solution for gravity loads.
Mechanical fit: bearings, backlash and shock
| Decision / input | Known / unknown | Action / verification |
|---|---|---|
| Gear material | Sintered metal, cut steel and hybrid stages are options; strength and noise depend on geometry and build. | Obtain stage materials, heat-treatment specification, allowable torque and a loaded noise test. |
| Radial / axial load | A diameter or bearing type alone does not establish allowable load. | Give force, direction and overhang distance; require catalog loads at that distance and required life. |
| Backlash / stiffness | Backlash is free angular play; elastic deflection under load is separate. | Define measurement torque, reversal direction, motor/gear state and output-angle acceptance limits. |
| Gear fatigue / shock | A generic material stress curve cannot establish this assembly’s endurance. | Give torque spectrum and reversals; ask for calculation assumptions and representative endurance records. |
Gear material
- Known / unknown
- Sintered metal, cut steel and hybrid stages are options; strength and noise depend on geometry and build.
- Action / verification
- Obtain stage materials, heat-treatment specification, allowable torque and a loaded noise test.
Radial / axial load
- Known / unknown
- A diameter or bearing type alone does not establish allowable load.
- Action / verification
- Give force, direction and overhang distance; require catalog loads at that distance and required life.
Backlash / stiffness
- Known / unknown
- Backlash is free angular play; elastic deflection under load is separate.
- Action / verification
- Define measurement torque, reversal direction, motor/gear state and output-angle acceptance limits.
Gear fatigue / shock
- Known / unknown
- A generic material stress curve cannot establish this assembly’s endurance.
- Action / verification
- Give torque spectrum and reversals; ask for calculation assumptions and representative endurance records.
For position control, specify output-angle accuracy after reversal and under load. An encoder on the motor shaft does not directly measure gearhead lost motion.
For impact or reversing loads, request a representative endurance plan. No universal fatigue limit or lifetime is assigned to a gear material here.
From estimated demand to a validated operating point
Demand a voltage/torque/speed/current curve for the exact winding and ratio. Check motor power, gearhead torque and allowed input RPM together. A rotating-load estimate cannot approve a stalled or jammed motor.
| Decision / input | Known / unknown | Action / verification |
|---|---|---|
| Loaded operating point | Torque, speed and power must be met simultaneously. | Measure voltage at motor terminals, current, output RPM and torque; record cold and stabilized values. |
| Thermal / duty | An insulation class does not define a universal torque derating multiplier. | Use the installed mounting/enclosure, ambient extremes and actual duty; agree winding/driver/gear limits. |
| Noise | Sound pressure at a stated distance and sound power are distinct. | Agree metric, instrument, fixture, load, distance, background correction and acceptance value. |
| EMC | A capacitor or filter recipe does not guarantee system compliance. | Evaluate the motor, controller, harness and enclosure together under the applicable end-product test plan. |
| Holding / power loss | Planetary stage count is not a safety brake rating. | Specify an independent rated brake or retention system; test power loss and worst-case load. |
Loaded operating point
- Known / unknown
- Torque, speed and power must be met simultaneously.
- Action / verification
- Measure voltage at motor terminals, current, output RPM and torque; record cold and stabilized values.
Thermal / duty
- Known / unknown
- An insulation class does not define a universal torque derating multiplier.
- Action / verification
- Use the installed mounting/enclosure, ambient extremes and actual duty; agree winding/driver/gear limits.
Noise
- Known / unknown
- Sound pressure at a stated distance and sound power are distinct.
- Action / verification
- Agree metric, instrument, fixture, load, distance, background correction and acceptance value.
EMC
- Known / unknown
- A capacitor or filter recipe does not guarantee system compliance.
- Action / verification
- Evaluate the motor, controller, harness and enclosure together under the applicable end-product test plan.
Holding / power loss
- Known / unknown
- Planetary stage count is not a safety brake rating.
- Action / verification
- Specify an independent rated brake or retention system; test power loss and worst-case load.
Duty terminology: S1 reaches thermal equilibrium at constant load; S2 requires a stated run duration followed by full cooling; S3 repeats on/off cycles with starting losses insignificant to heating. If starts or acceleration add significant heat, provide that profile for a different duty assessment. Duty reference.
Agree the end-product EMC test plan with the responsible laboratory. Filters, cable routing, driver switching and enclosure design are configuration-dependent.
Envelope requests are not frame ratings
The sizer offers 10, 12, 16, 20, 22, 24, 28, 32, 36 and 42mm as requested outer diameters. These options do not establish stocked models, allowable torque, shaft loads or overall length. Ask the supplier to confirm all four checks below.
| Decision / input | Known / unknown | Action / verification |
|---|---|---|
| Motor + gearhead torque | Unknown for every diameter option on this page. | Confirm continuous/intermittent limits for the exact winding and ratio. |
| Power + speed | Calculator reports required power, not available power. | Match motor power and gearbox input-speed limits to the requested point. |
| Dimensions + bearings | Shaft, length, mounting and bearing capacity are unconfirmed. | Approve a dimensioned drawing and load-life data. |
| Availability + quote | No stock, MOQ, price or lead-time commitment. | Request dated terms for the approved configuration and quantity. |
Motor + gearhead torque
- Known / unknown
- Unknown for every diameter option on this page.
- Action / verification
- Confirm continuous/intermittent limits for the exact winding and ratio.
Power + speed
- Known / unknown
- Calculator reports required power, not available power.
- Action / verification
- Match motor power and gearbox input-speed limits to the requested point.
Dimensions + bearings
- Known / unknown
- Shaft, length, mounting and bearing capacity are unconfirmed.
- Action / verification
- Approve a dimensioned drawing and load-life data.
Availability + quote
- Known / unknown
- No stock, MOQ, price or lead-time commitment.
- Action / verification
- Request dated terms for the approved configuration and quantity.
Compare quotations and landed cost on the same basis
| Decision / input | Known / unknown | Action / verification |
|---|---|---|
| Samples / MOQ / lead time | Unconfirmed: no dated factory quotation is available on this page. | Separate sample, pilot and production quantities; quote dates from drawing approval and state stock assumptions. |
| Unit price / NRE | Unconfirmed: shaft, winding, encoder, sealing and testing can change cost. | Itemize tooling ownership, revision charges, controller, inspection, packaging and warranty terms. |
| Landed cost | Unit price alone excludes transport, duties, clearance and other charges. | Compare the same Incoterm, destination and date: goods + tooling allocation + freight + insurance + duties + fees. |
| Customs / compliance | Classification, trade measures and exemptions depend on the actual product and destination. | Confirm current tariff classification with the importer/broker; request material declarations tied to part and revision. |
| Air freight / packaging | Magnetized cargo assessment and carrier acceptance depend on the packed shipment. | Ask the forwarder for current rules and any required test/shielding; protect shafts and document transit inspection. |
Samples / MOQ / lead time
- Known / unknown
- Unconfirmed: no dated factory quotation is available on this page.
- Action / verification
- Separate sample, pilot and production quantities; quote dates from drawing approval and state stock assumptions.
Unit price / NRE
- Known / unknown
- Unconfirmed: shaft, winding, encoder, sealing and testing can change cost.
- Action / verification
- Itemize tooling ownership, revision charges, controller, inspection, packaging and warranty terms.
Landed cost
- Known / unknown
- Unit price alone excludes transport, duties, clearance and other charges.
- Action / verification
- Compare the same Incoterm, destination and date: goods + tooling allocation + freight + insurance + duties + fees.
Customs / compliance
- Known / unknown
- Classification, trade measures and exemptions depend on the actual product and destination.
- Action / verification
- Confirm current tariff classification with the importer/broker; request material declarations tied to part and revision.
Air freight / packaging
- Known / unknown
- Magnetized cargo assessment and carrier acceptance depend on the packed shipment.
- Action / verification
- Ask the forwarder for current rules and any required test/shielding; protect shafts and document transit inspection.
No commercial ranges on this page are a factory offer. Confirm custom shaft/winding/encoder charges in writing. For a common comparison, allocate tooling across the same forecast quantity and compare identical inspection and delivery scope.
Time-sensitive references, checked 2026-10-31: USITC tariff schedule and official RoHS amendment. Recheck the applicable rules at shipment; no blanket duty rate, material exemption or freight acceptance is assumed.
Failure modes, cost risks and alternatives
| Decision / input | Known / unknown | Action / verification |
|---|---|---|
| Using stall torque as a working rating | Stall has zero shaft speed; a current estimate at a rotating load does not describe it. | Require a continuous load point and startup/stall limits; apply current limiting and validate jam response. |
| Small frame with high power demand | A plausible torque number alone can hide excessive motor power or heat. | Compare both motor power and gearhead torque/input-speed limits. Consider a larger drive or reduced load/speed. |
| Sample-to-production drift | A selected prototype is insufficient evidence of consistent volume quality. | Use a signed drawing, retained sample, pilot batch, inspection plan and controlled changes. |
| Low unit price with hidden scope | Quotes may omit driver, tooling, tests, export packaging or customs charges. | Use the same RFQ fields and cost boundary; compare total landed cost and delivery conditions. |
Using stall torque as a working rating
- Known / unknown
- Stall has zero shaft speed; a current estimate at a rotating load does not describe it.
- Action / verification
- Require a continuous load point and startup/stall limits; apply current limiting and validate jam response.
Small frame with high power demand
- Known / unknown
- A plausible torque number alone can hide excessive motor power or heat.
- Action / verification
- Compare both motor power and gearhead torque/input-speed limits. Consider a larger drive or reduced load/speed.
Sample-to-production drift
- Known / unknown
- A selected prototype is insufficient evidence of consistent volume quality.
- Action / verification
- Use a signed drawing, retained sample, pilot batch, inspection plan and controlled changes.
Low unit price with hidden scope
- Known / unknown
- Quotes may omit driver, tooling, tests, export packaging or customs charges.
- Action / verification
- Use the same RFQ fields and cost boundary; compare total landed cost and delivery conditions.
Minimum RFQ package for a China motor supplier
| Decision / input | Known / unknown | Action / verification |
|---|---|---|
| Load & electrical | 12V operating window; simultaneous torque and loaded speed; startup/jam behavior. | Attach calculator text; add measured load profile, current limits and allowable speed tolerance. |
| Envelope & mechanics | Maximum OD/length, mount, shaft drawing, radial/axial load and overhang. | Attach a dimensioned drawing with tolerances and required bearing/load life. |
| Duty & environment | Run/rest/starts, ambient, mounting, enclosure, vibration and expected cycles. | Specify acceptance conditions rather than asking for a generic lifetime promise. |
| Acceptance & commercials | Noise/backlash limits, feedback/driver, quantities, destination and delivery term. | Request exact part/revision, loaded curve, test plan, dated itemized quote and production change policy. |
Load & electrical
- Known / unknown
- 12V operating window; simultaneous torque and loaded speed; startup/jam behavior.
- Action / verification
- Attach calculator text; add measured load profile, current limits and allowable speed tolerance.
Envelope & mechanics
- Known / unknown
- Maximum OD/length, mount, shaft drawing, radial/axial load and overhang.
- Action / verification
- Attach a dimensioned drawing with tolerances and required bearing/load life.
Duty & environment
- Known / unknown
- Run/rest/starts, ambient, mounting, enclosure, vibration and expected cycles.
- Action / verification
- Specify acceptance conditions rather than asking for a generic lifetime promise.
Acceptance & commercials
- Known / unknown
- Noise/backlash limits, feedback/driver, quantities, destination and delivery term.
- Action / verification
- Request exact part/revision, loaded curve, test plan, dated itemized quote and production change policy.
Start with the tool’s RFQ text, complete the missing fields and ask for a configuration-specific review. If load is unknown, measure mechanism force and lever arm (T = force × perpendicular radius) before committing to a motor. If that measurement is unavailable, send drawings and the load motion profile for engineering assistance.
Return to sizer and prepare requirements ↑Three reproducible planning examples
Hypothetical calculations using the tool defaults unless stated. These are not customer projects, approved designs, quotations or measured outcomes.
Lock latch — periodic load
Input: 0.45 N·m at 45 RPM. Requested envelope: 16mm.
Calculate: 128.89:1 target ratio, 3 estimated stages, 2.12W output, 0.42A estimated running current.
Next: Supply latch force/travel, start/jam current, cycles and battery window. The 16mm envelope remains unverified.
Pump — continuous load
Input: 0.75 N·m at 80 RPM. Requested envelope: 22mm.
Calculate: 72.50:1 target ratio, 3 estimated stages, 6.28W output, 1.25A estimated running current.
Next: Test flow under pressure, pulsation, noise and thermal equilibrium. A rotor or gear material does not establish medical suitability.
Steering — reversing load
Input: 4.8 N·m at 50 RPM. Requested envelope: 36mm.
Calculate: 116.00:1 target ratio, 3 estimated stages, 25.13W output, 5.02A estimated running current.
Next: Add inertia, shock spectrum, encoder/control needs, bearing loads and brake requirements. No AGV drive approval is implied.
Sizing, supplier and commercial questions
Sizing
What does the 12V China motor sizer actually calculate?
It calculates a target ratio, estimated minimum stage count, output power and operating current from your load and explicit efficiency assumptions. It does not select a stocked SKU or establish a thermal rating.
Are the default motor speed and efficiencies measured data?
No. The defaults (5,800 loaded motor RPM, 68% motor efficiency and 85% per-stage efficiency) are illustrative planning inputs. Replace them with data at the intended operating point.
Can I use the current result to size a driver or fuse?
Use it only as an initial running-load estimate. Starting, acceleration, stall, driver losses and protection behavior require separate manufacturer data and testing.
Does selecting a 22mm frame guarantee the requested torque?
No. Diameter is an envelope request. Match the exact motor winding and ratio to continuous torque, power, input-speed and thermal limits.
Is the calculated reduction ratio available from a supplier?
Availability is unconfirmed. Suppliers offer discrete tooth-count combinations. Ask for the actual ratio and recalculate loaded speed and current using the corresponding data.
Why not estimate continuous torque from stall torque?
A universal fraction cannot replace model-specific motor and gearhead limits. Ask for a loaded operating curve and a continuous rating at the actual mounting and ambient conditions.
What is the difference between S2 and S3 duty?
S2 is a limited run followed by enough rest to return to ambient temperature. S3 is repeated load/rest cycling. Include timings and starting behavior; neither label automatically permits a peak torque.
Can a high-ratio planetary drive hold a vertical load without power?
Do not rely on ratio alone. Friction-dependent holding varies with the complete drive and conditions. Specify an independently rated holding brake or other retention mechanism and verify it.
Supplier evaluation
How do I assess a China factory rather than a marketplace listing?
Verify the legal manufacturing site, process ownership, drawing control, calibration, sample reports and subcontracting scope. Geography and badges alone do not establish quality.
Are supplier certifications verified on this page?
No supplier-specific certification or factory audit report is supplied. Request current certificates with the correct legal entity, site, scope and issuer verification.
Does a coreless or BLDC motor guarantee longer service life?
No guaranteed life is assigned here. Confirm commutation and bearing design, controller compatibility and endurance under your load, environment and duty.
How should I compare noise claims?
Use the same metric, load, speed, mounting, distance and background conditions. A single sound-pressure reading at 30cm is not a sound-power measurement under ISO 3744.
What should accompany prototype samples?
Request the approved drawing revision, identifiable part/batch, dimensional results, loaded torque-speed-current measurements and agreed thermal/noise checks. Use a pilot batch to assess repeatability.
Commercial
What are the unit price, MOQ and delivery time?
These are unconfirmed until a supplier issues a dated quotation for the exact winding, ratio, shaft, driver, test scope, quantity and delivery term.
Are standard shaft changes always free of tooling charges?
No. Confirm machining scope, tooling ownership, drawing revisions and one-time charges in the quote. Existing tooling does not guarantee zero NRE or a delivery date.
What tariff and RoHS exemption apply to my order?
Use the current official rules for the exact product, origin, destination, equipment category and shipment date. Obtain classification and material evidence; no fixed duty rate or exemption approval is provided here.
Sources, dates and evidence limits
Access/review date: 2026-10-31. Manufacturer sources support general principles; they do not validate an MPM product or a supplier’s test claims. The ISO listing establishes scope only. Standards and legal references need the applicable edition and configuration-specific evidence.
FAULHABER: gearhead technical information, pp.117, 119–120
Scope / limit: Model-specific continuous/intermittent torque, input-speed and power limits; efficiency depends on operating point. Does not validate any MPM model.
maxon: self-locking and backdrivability
Scope / limit: Distinguishes intrinsic locking from friction-dependent holding; behavior depends on the complete drive. No universal ratio threshold guarantees holding.
ABB Motor Guide (July 2019), §4.7, p.46: duty types
Scope / limit: S1 continuous running, S2 short-time with full cooling, S3 periodic operation. Terminology reference, not a miniature-motor thermal rating.
ISO 3744:2025 — acoustic sound power
Scope / limit: Sound power determined from a measurement surface. A single 30cm sound-pressure reading is a different metric. Public scope only; no laboratory test report is supplied here.
USITC: current Harmonized Tariff Schedule
Scope / limit: Look up destination-specific classification and effective duties for the actual shipment. No fixed landed-cost duty rate is assumed on this page.
EUR-Lex: RoHS alloy exemption amendment (EU) 2025/2364
Scope / limit: Official amendment entry. Confirm current consolidated wording, equipment category and shipment date before relying on an exemption; this page does not certify product compliance.
Request a configuration-specific engineering review
Send your load, loaded speed, duty, envelope, drawing, quantity and destination. Ask for the actual ratio, validated operating limits and dated sample/production quotation.
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