Robot joints and actuation
smart servo: 3.92 N·m peak, 85 rpm no-load.
Engineering inference
Waveshare
Waveshare ST3025 Servo 40 kg·cm 12 V
Waveshare ST3025 serial bus servo: 40 kg·cm (3.92 N·m) locked-rotor torque at 12 V, 85 rpm no-load, 6–12.6 V input, metal case, brushless motor, steel gears, 1.5 A rated current, 12-bit 360° magnetic encoder, servo / speed-loop motor / step modes, TTL bus to 1 Mbps with up to 253 IDs, current and temperature feedback, 40 × 20 × 40 mm.
ST3025Development boardPrice$79.99www.waveshare.com · in stock
Buy at www.waveshare.com Overview
Motor essentials
Facts about the complete product. Unknown values remain open design questions.
- Rated voltage
- 12.6 V
- No-load speed
- 85 RPM
- Encoder
- 360° magnetic, 12-bit (4096 per turn)
A good fit for
Guidance to help you shortlist. The basis is shown for each recommendation.
No-load speed, rated performance and stall limits describe different operating points. A stall specification is not a continuous operating rating.
3D model & CAD
3D model & CAD files
Generated from the datasheet's dimensioned drawing and measured against it. Download the STEP to check fit in your own enclosure.
- Envelope (L × W × H)
- 40 × 20 × 40 mm
- Verification
- generated
- Envelope complete
- Yes
Torque & control
Torque, speed and control
What the joint can deliver and how the controller talks to it.
- Type
- SMART_SERVO
- No-load speed
- 85 rpm
- Encoder
- 360° magnetic, 12-bit (4096 per turn)
- Control
- TTL · position (angle servo mode), speed closed-loop (motor mode), step
| Connector | Type |
|---|---|
| ttl_bus | TTL bus servo interface, two ports for daisy-chaining |
Rated torque is continuous; peak torque is short-duration. Values with two figures (e.g. 24/48 V) are per supply voltage.
Specifications
Motor performance
No-load, rated-load and stall figures retain their separate test conditions.
- Rated voltage
- 12.6 V
- No-load speed
- 85 RPM
- Rated current
- 1.5 A
Stall torque and current are not continuous ratings. Check the duty cycle and starting load when choosing the driver and power supply.
Thermal limits by level
Product operating conditions, chip ambient ratings, package case limits and junction maxima remain separate.
Motor body
Mechanical dimensions
Reported product dimensions may exclude protruding components. Unknown height does not establish a complete clearance envelope.
- Length
- 40 mm
- Width
- 20 mm
- Reported height / thickness
- 40 mm
Attached generated geometry is an approximate envelope. A generated outline does not establish an electrically verified PCB footprint.
Board connectors
| ID / type | Pins | Pitch | Notes |
|---|---|---|---|
| ttl_busTTL bus servo interface, two ports for daisy-chaining | Unknown | Unknown | — |
Complete structured record
Every available field, including details beyond the summaries. Null means the value has not been established.
Sourcing & files
Supplier offers
US / USD is the target market. Observed price and stock are separate from a delivery quote.
www.waveshare.com
US · USD
$79.99Minimum quantity unknown
- Observed stock
- in stock
- Checked
- Oct 1, 2026, 05:19 PM UTC
- Delivery estimate
- Not quoted
Observed within the last 24 hours. Confirm the current supplier quote.
Visit supplier (opens in a new tab)Delivery depends on quantity, postal code and shipping method. A dispatch statement such as “ship today” is not an arrival estimate.
Design files and references
Each source keeps its own verification status. Confirm the part revision and file contents before using it in a design.
Datasheet (opens in a new tab)
Manufacturer reference
Waveshare ST3025 Servo — product photo (opens in a new tab)
Manufacturer reference
main product image of the ST3025 page
STEP (generated from datasheet drawing) — link unavailable
Generated asset
cad_check passed
Generated envelope geometry may also exist for this record. It does not replace manufacturer CAD or a verified electrical land pattern.
Source evidence
Document provenance, retrieval dates and the field groups supported by each source.
Supports: spec.constraints.electrical.supply_voltage_max_v, spec.constraints.electrical.supply_voltage_min_v, spec.geometry.body_length_mm, spec.geometry.cad.bbox.height_mm, spec.geometry.cad.bbox.length_mm, spec.geometry.cad.bbox.width_mm, spec.geometry.cad.envelope_complete, spec.geometry.cad.mesh_path, spec.geometry.cad.step_path, spec.geometry.cad.verification, spec.geometry.dimensions.height_mm, spec.geometry.dimensions.length_mm, spec.geometry.dimensions.width_mm, spec.provides.actuator_type, spec.provides.control_interface, spec.provides.control_modes, spec.provides.encoder, spec.provides.encoder_bits, spec.provides.features, spec.provides.integrated_driver, spec.provides.kt_nm_per_a, spec.provides.motor_type, spec.provides.no_load_speed_rpm, spec.provides.peak_torque_nm, spec.usage.connectors, spec.usage.pinout_complete, spec.usage.requirements.other.peak_current_a, spec.usage.requirements.rated_current_a, spec.usage.requirements.rated_voltage_v
sha256 684a18dbad8adc9684d77193d68bd5c633f192b3f11b44d2e5963622719e0d7e
Supports: offers
FAQ
Waveshare ST3025 Servo 40 kg·cm 12 V questions
What voltage powers the Waveshare ST3025 Servo 40 kg·cm 12 V?
Supply range 6–12.6 V.
How much does the Waveshare ST3025 Servo 40 kg·cm 12 V cost?
From $79.99 at www.waveshare.com. Prices are observed unit prices before tax and shipping.
What are the Waveshare ST3025 Servo 40 kg·cm 12 V dimensions?
40 × 20 × 40 mm. A STEP model is available for enclosure fit checks.
Where does this Waveshare ST3025 Servo 40 kg·cm 12 V data come from?
Every value in this record is traced to a source — 2 documents including the board and chip datasheets — with the page and table cited per value. Unknowns are left explicit, never guessed.