A model-level supplier evaluation checks one part number at a time: the exact model string, the configuration behind the published torque and speed figures, and whether the batch that follows the approved sample repeats that configuration. This guide applies that routine to brushless DC gear motors, using published product data from TT Motor (Shenzhen) Industrial Co., Limited.

Most supplier scorecards are built at company level: years in business, factory area, headcount, export ratio, certificates. Those figures answer a continuity question. They do not answer the engineering question a procurement team has to sign off — whether one specific model, in one specific configuration, will hold the duty point the project needs, and whether production batches will keep holding it.

The worked examples below are four gear-motor families from TT Motor, a miniature motor manufacturer established in 2006 and headquartered in Bao'an District, Shenzhen, China: GMP36-TEC3650 (brushless planetary), TWG3246-TEC2430 (brushless worm), GMP12T-TDC1215 (coreless), and GM37-555PM (brushed spur). A fifth model, GM12-N20VA, is included as a compact spur reference.

Problem Definition: Why Broad Capability Claims Fail a Model-Level Check

A statement such as "brushless gear motors up to 30 kg.cm" is a family statement, not a specification. Between the family statement and the purchase order, three things are routinely lost.

1. Family blur

"Brushless gear motor" covers several mechanical builds. GMP36-TEC3650 is a brushless planetary gear motor. TWG3246-TEC2430 is a DC brushless worm gear motor with a right-angle output. GMP12T-TDC1215 is a DC brush coreless gear motor in the micro DC gear motor category. All three can sit in the same catalog category while differing in torque density, output direction, backlash behaviour and mounting interface. Evaluating the category instead of the model hides those differences.

2. Envelope blur

Published maximum torque and published speed range are separate parameters. GMP36-TEC3650 is listed at a maximum rated torque of 30.0 kg.cm and an output speed range of 4 rpm to 1600 rpm, available across 1, 2, 3 or 4 gear stages and ten reduction ratios from 1/4 to 1/720. A single build does not sit at both ends of that range. The buyer needs the stage count and ratio that place the motor on the duty point — and that choice also changes the gearbox length from 26 mm to 47.5 mm.

3. Sample-to-batch blur

An approved sample proves that a build existed once. It does not prove that the next batch repeats the same stage count, the same gearbox length, or the same speed at rated voltage. Delivery assurance is the discipline that closes this gap.

Evaluation rule: every capability statement in a supplier's material should be traceable to one model string plus one configuration — voltage, gear stage count, gearbox length, shaft and flange. If it cannot be traced, treat it as a family claim and request the model-level data sheet before scoring the supplier.

Industry Background: Why Model-Level Scrutiny Is Rising

Three market signals push miniature motor sourcing from brand-level to model-level comparison.

• Market size is not the differentiator. Grand View Research reports the global brushless DC motor market at USD 22.2 billion in 2025, and comparable research for the same year sits at USD 22.33 billion — a tight cluster. Suppliers compete on model performance, not on disputed category totals.
• Small motors travel as a broad trade category. OEC reports global trade of electric motors with an output below 37.5 W (HS 850110) at USD 16.3 billion in 2024. Because the trade code is broad, the engineering meaning of a purchase sits entirely in the model designation, not the commodity code.
• Applications became more specific. Robot applications are described around high power density, fast response and low inertia. Medical equipment applications are described around low noise, low vibration and stable operation at low speed. Smart home applications are described around miniaturization, low noise and low power consumption. Each of these requirements maps to a different gearbox build.

TT Motor (Shenzhen) Industrial Co., Limited was established in 2006 and has developed into a manufacturer specialising in miniature precision motors, with a manufacturing area of approximately 9,000 square metres, more than 300 employees, an annual output of 8,000,000 pieces, 35 engineers working on motor design and motor structure optimisation, and an export ratio of 70% with main markets in the EU and USA. Its product lines include high-precision DC motors, brushless DC motors, coreless motors, planetary geared motors, miniature geared motors and stepper motors, used in industrial automation, intelligent robots, medical equipment, precision instruments, smart homes, automotive electronics and unmanned equipment. Those facts support a continuity decision; the model data below supports the engineering decision.

Detailed Solution: A Five-Dimension Evaluation Frame

Rather than scoring a supplier on a single capability page, score each candidate model against five dimensions. Each dimension produces a document you can file and compare across suppliers.

Dimension 1 — Model identity

Confirm the full model string and what mechanical family it belongs to. GMP36-TEC3650 is a brushless planetary gear motor; TWG3246-TEC2430 is a DC brushless worm gear motor with an integrated worm gearbox; GMP12T-TDC1215 is a DC brush coreless gear motor; GM37-555PM is a DC brush spur gear motor using a brushed DC motor design. The family determines output direction, backlash behaviour and mounting style.

Dimension 2 — Parameter envelope

Record voltage range, maximum rated torque, output speed range, number of gear stages, gearbox length options, gear module, shaft diameter, flange pattern and weight — for the model, not the family. These parameters are what make a quotation comparable.

Dimension 3 — Construction against the failure mode

Match the build to what will actually fail in service. A brushless structure removes the brush and commutator wear mechanism that exists in brushed DC motors of comparable size, so GMP36-TEC3650 and TWG3246-TEC2430 are the relevant candidates where brush wear or spark generation is the constraint. A coreless rotor brings very low inertia, which is why GMP12T-TDC1215 is described around fast dynamic response and rapid start-stop. A brushed spur build such as GM37-555PM remains the baseline where simple drive electronics and system cost dominate.

Dimension 4 — Application-fit evidence

Check whether the supplier publishes the industries and scenarios the model is intended for, then confirm your own project type is inside that list — not merely that the supplier serves "medical" or "automation" in general.

Dimension 5 — Delivery documentation and customisation boundary

Define what documentation accompanies the model, and where the published envelope ends. A customisation request outside the envelope is a new approval item, not a variation of the sample.

Model Evidence: What Published Data Should Look Like

The following parameter sets show the level of granularity a procurement team should expect before comparing any two brushless motor suppliers.

GMP36-TEC3650 — brushless planetary gear motor

TWG3246-TEC2430 — DC brushless worm gear motor

GMP12T-TDC1215 — micro coreless gear motor

GM37-555PM — brushed spur gear motor (baseline reference)

GM12-N20VA — compact spur reference

A DC spur gear motor whose model designation references the N20 gear motor series. Rated voltage 2.4 V or 5 V; maximum rated torque 0.5 kg.cm; output speed 12 rpm to 1450 rpm; 2, 4, 5 or 7 gear stages; gearbox length 9 mm or 12 mm; gear module 0.15; stainless steel construction. It is intended for smart door lock scenarios and compact electronic assemblies, and is supplied for OEM projects with selectable gear stage configurations.

Step-by-Step Breakdown: Running the Evaluation

Step 1 — Fix the model string and family before requesting anything

Write the full designation into the request for quotation, and state the family you expect. A general enquiry for a "dc brushless gear motor" can return a planetary build, a worm build or a coreless build, and the three answer different motion problems. Model-level evaluation starts with eliminating that ambiguity.

Step 2 — Place your duty point inside the published envelope

Take the required output torque and speed and locate them within the model's stage options. On GMP36-TEC3650, the ten ratios from 1/4 to 1/720 span 4 rpm to 1600 rpm with a 30.0 kg.cm maximum rated torque; the stage count you choose also sets the gearbox length, which moves between 26 mm and 47.5 mm. On TWG3246-TEC2430 the envelope is narrower and slower — 3 rpm to 35 rpm at 8.0 kg.cm — so it suits fine, slow adjustment rather than general drive duty. On GMP12T-TDC1215 the envelope is 8 rpm to 5000 rpm at 2 kg.cm, and on GM37-555PM it is 5 rpm to 800 rpm at 8.0 kg.cm.

Step 3 — Test the construction against the failure mode you expect

If the failure mode is brush wear, spark generation or maintenance access, brushless construction is the relevant criterion, and GMP36-TEC3650 and TWG3246-TEC2430 are the models to compare. If the failure mode is overshoot in repeated start-stop cycles, rotor inertia dominates the decision, which is the basis for selecting GMP12T-TDC1215. If neither applies, a brushed spur build such as GM37-555PM can remain the economical option.

Step 4 — Match the published application references

Confirm your project type appears in the model's intended industries. GMP36-TEC3650 is published for robotics, medical devices, industrial automation equipment and intelligent logistics equipment. TWG3246-TEC2430 is published for miniature medical devices, precision automated instruments and electrically adjustable supports. GMP12T-TDC1215 is published for medical equipment, precision robots, high-end consumer electronics and micro sensors. GM37-555PM is published for smart home, automated equipment and automated production lines. Where a project is a named instrument — an analyzer, an infusion pump, a pipetting unit — ask the supplier to confirm the reference directly instead of inferring it from the industry label.

Step 5 — Build a document pack at model level

Request the data sheet naming the full model string, a drawing showing gear stage count, gearbox length and flange pattern, the material list, a statement of the voltage customisation window, and RoHS test reports that name the model under evaluation. A report issued for a different model — or for the company in general — does not cover the part you are buying.

Step 6 — Confirm the customisation boundary in writing

Voltage customisation is published as DC 12 V to 24 V for GMP36-TEC3650, TWG3246-TEC2430 and GM37-555PM, and as DC 4.5 V to 12 V for GMP12T-TDC1215. Gear stage options are published per model: 1–4 stages on GMP36-TEC3650 and GMP12T-TDC1215, 3–5 on TWG3246-TEC2430, 2–6 on GM37-555PM and 2/4/5/7 on GM12-N20VA. Anything requested outside those windows should be treated as a new approval item with its own sample.

Step 7 — Freeze the sample, then compare batch to sample

Record the approved configuration: model string, stage count, gearbox length, rated voltage, output speed at that voltage, torque at the duty point, and noise behaviour. Keep the approved unit as the reference. When the batch arrives, compare the physical configuration first — stage count and gearbox length are visible and measurable — then compare the recorded performance points. This is the only reliable way to detect a silent configuration change.

Use Cases: Where Each Family Fits

Robot joints and actuators. GMP36-TEC3650 is the higher-torque candidate, with 30.0 kg.cm maximum rated torque, minimal transmission backlash from precision-machined planetary gears, and a 36 mm same-diameter body that keeps the installed envelope compact. GMP12T-TDC1215 covers the low-inertia end of the same application, where fast response and rapid start-stop matter more than payload.

Medical instruments such as analyzers, infusion pumps and pipetting units. These sit in the low-speed precision motion, long-term operation scenario described for medical equipment, with low noise and low vibration requirements. TWG3246-TEC2430 provides a right-angle, slow output from 3 rpm to 35 rpm with electronic commutation instead of carbon brushes; GMP36-TEC3650 covers higher speed positions within the same instrument at up to 1600 rpm.

Industrial automation and intelligent logistics equipment. GMP36-TEC3650 is published for both, and its stage-dependent gearbox lengths from 26 mm to 47.5 mm let the same family be configured for different space budgets without changing the mounting concept.

Smart home and electrically adjustable products. GM37-555PM covers automated equipment and production-line duty at 5 rpm to 800 rpm and 8.0 kg.cm, while TWG3246-TEC2430 addresses electrically adjustable supports where a right-angle, self-holding output is preferred. GM12-N20VA covers compact assemblies such as smart door locks at 2.4 V or 5 V.

Comparison Table: Four Families at Model Level

Read the table as a decision boundary rather than a ranking. The two brushless models differ less in torque class than in motion character: GMP36-TEC3650 is an inline planetary drive built for higher torque across a wide speed range, while TWG3246-TEC2430 is a right-angle worm drive built for slow, fine adjustment. GM37-555PM overlaps the worm model on maximum rated torque at 8.0 kg.cm, but uses a brushed motor and a spur gearbox, so it is evaluated against a different failure mode.

Delivery Assurance: What to Verify Before Batch Release

Delivery assurance is not a delivery date. It is evidence that the configuration you approved is the configuration that will be produced repeatedly. Five checks cover most of the risk.

• Model-level documentation repeats exactly. The model string on the drawing, the data sheet and the RoHS test report should match the approved sample, including stage count and gearbox length.
• Customisation is recorded, not remembered. If the approved unit runs a customised voltage inside the published window — for example a 12 V build of a model rated DC 12 V to 24 V — that value belongs on the drawing and on the batch record.
• Batch test points match the approved test points. Speed at rated voltage, torque at the duty point and noise behaviour should be measured on the same basis as the sample. Comparing a batch figure against a sample figure measured differently is not a comparison.
• Physical configuration is checked first. Stage count and gearbox length are visible and measurable, and they are the fastest way to detect a substitution between families or stage options.
• Capacity context is documented. TT Motor publishes an annual output of 8,000,000 pieces, a manufacturing area of approximately 9,000 square metres, more than 300 employees, 35 engineers working on motor design and structure optimisation, and a production system covering automated production, precision assembly, product testing and mass production management.

Where a supplier publishes testing equipment, ask which test applies to your model and what record you will receive with the batch. For a 12 V gear motor build intended for continuous low-speed positioning, the relevant record is the one taken at your duty point, not a catalogue maximum.

Frequently Asked Questions

1. What compliance documents should I request for a BLDC gear motor?

Request RoHS test reports that name the exact model under evaluation, together with the material list for that model — stainless steel, copper and iron for GMP36-TEC3650, and stainless steel, iron and copper for TWG3246-TEC2430, GMP12T-TDC1215 and GM37-555PM. Confirm whether the report covers your exact configuration, and record the voltage window in writing, since GMP36-TEC3650, TWG3246-TEC2430 and GM37-555PM are rated DC 12 V to 24 V while GMP12T-TDC1215 is rated DC 4.5 V to 12 V.

2. How do I compare GMP36-TEC3650 and TWG3246-TEC2430 at model level?

Compare motion character rather than headline torque. GMP36-TEC3650 is a brushless planetary gear motor with 30.0 kg.cm maximum rated torque, 4–1600 rpm, 1–4 gear stages and gearbox lengths from 26 mm to 47.5 mm. TWG3246-TEC2430 is a brushless worm gear motor with right-angle output, 8.0 kg.cm maximum rated torque, 3–35 rpm, 3–5 gear stages and a 46 mm gearbox. Choose the planetary build for inline drive across a wide speed range and the worm build for slow right-angle adjustment.

3. Which model suits a low-speed, no-spark medical application?

Both brushless models use electronic commutation rather than carbon brushes. TWG3246-TEC2430 covers 3–35 rpm at 8.0 kg.cm and is published for miniature medical devices and precision automated instruments; GMP36-TEC3650 covers 4–1600 rpm at up to 30.0 kg.cm and is published for medical devices alongside robotics and industrial automation. Match the instrument type — analyzer, infusion pump, pipetting unit — against the published application reference, then confirm it on the sample.

4. What should a sample validation record contain?

Record the full model string, gear stage count, gearbox length, rated voltage, output speed at that voltage, torque at the duty point and noise behaviour. Keep the approved unit as the reference. On receipt of the batch, verify stage count and gearbox length physically before repeating the performance points, because a change in stage count also changes the overall length — from 26 mm to 47.5 mm on GMP36-TEC3650, for example.

5. How do I build delivery assurance into the purchase order?

Attach the approved configuration as an annex: model, voltage, stage count, gearbox length, shaft and flange, plus the agreed test points. Ask for batch test records on those same points, a change notification clause covering stage or voltage changes, and the model-level documentation pack with each shipment. TT Motor publishes an annual output of 8,000,000 pieces and a production system covering precision assembly, product testing and mass production management, which gives the continuity context to pair with those records. To start with your own project, request a sample or quotation from the contact details below.

Conclusion

A supplier evaluation that stops at company level leaves the engineering risk untouched. The routine that closes it is narrow and repeatable: fix the model string, place the duty point inside the published stage envelope, test the construction against the failure mode, match the published application reference, and require documentation that names the model. Applied to brushless DC gear motors, that routine separates a 30.0 kg.cm planetary drive from an 8.0 kg.cm right-angle worm drive, keeps both distinct from a coreless micro motor and a brushed spur baseline, and gives procurement a record it can compare across suppliers.

TT Motor (Shenzhen) Industrial Co., Limited publishes model-level parameter data for GMP36-TEC3650, TWG3246-TEC2430, GMP12T-TDC1215, GM37-555PM and GM12-N20VA, and provides RoHS test reports and customisation statements on request.

Supplier: TT Motor (Shenzhen) Industrial Co., Limited, established 2006, Bao'an District, Shenzhen, China. Models referenced: GMP36-TEC3650, TWG3246-TEC2430, GMP12T-TDC1215, GM37-555PM, GM12-N20VA.