Harmonic actuator
Laifual Drive AC high-voltage joint modules harmonic actuator
Harmonic-geared joint modules for 220 V AC external servo drives, from M70 to M190 (70–190 mm diameter), ratios 51–121, with 17-bit or 23-bit single-turn plus 16-bit multi-turn encoders over BiSS-C or Tamagawa and optional brake.
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What are you specifying?
Select everything you need. A motor, drive and gearbox can be specified together as one axis.
Key specifications
| Outer diameter | 70–190 mm |
|---|---|
| Data / bus | BiSS-C, Tamagawa |
| Supply | 220 VAC via external servo drive |
| Feedback | 17-bit single-turn + 16-bit multi-turn, or 23-bit + 16-bit (Tamagawa only) |
| Ratio | 51–121:1 |
| Resolution (max) | 23 bit |
| Brake | standard type with brake; basic type without |
| Models | M70, M80, M90, M110, M142, M170, M190 |
Summarised in our own words from Zhejiang Laifual Harmonic Drive Co., Ltd. (HKEX: 03952)'s published data; series maxima, individual models vary. Last checked 2026-10-30. Source 1
Notes on this data
Torque and mass not stated on the page.
Specify Motion is not affiliated with Zhejiang Laifual Harmonic Drive Co., Ltd. (HKEX: 03952). Laifual Drive and AC high-voltage joint modules are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
Laifual Drive AC high-voltage joint modules replacement and alternative options
Use these supply-network options as a starting point for an engineering check. We can also help source the original Laifual Drive part. Published series figures do not establish an exact-model or drop-in replacement: confirm ratings, fit, interfaces and approvals for your application.
Hollow-shaft harmonic servo actuator: strain-wave gearing, motor, encoder and brake in one unit, run from a separate servo drive. Six frame sizes, from 48 VDC to 220 VAC.
Large-bore version of the harmonic actuator with a frameless 16-pole motor, giving a much bigger through-hole for cabling. Two sizes.
Harmonic actuator with an integrated German-made Synapticon Circulo servo drive on EtherCAT, with STO and optional FSoE functional safety.
Figures are the highest published for each series and are not always measured the same way. A higher figure is not automatically a better choice: mounting, duty cycle, feedback, connectors and approvals matter too. An engineer will check the fit against your application before recommending anything.
Typical applications
What a harmonic actuator is
A harmonic actuator is a rotary servo actuator that combines a strain-wave gear, a servo motor, a position encoder and often a brake in one compact housing. Many have a hollow shaft for cables, and some include the servo drive with a fieldbus interface. The strain-wave gear gives a high ratio with near-zero backlash, while a precision output bearing carries the load directly. The actuator is ready to mount as a robot joint or precision rotary axis.
When engineers choose a harmonic actuator
Choose a harmonic actuator for robot joints, positioners and precision rotary axes where compact size, zero backlash and fast integration matter. It saves the design effort of combining motor, gear, encoder and bearings. The trade-offs are cost and flexibility: the motor, gear ratio and feedback are fixed by the range, and torque limits are set by the strain-wave gear. For heavy shock loads, a cycloidal solution may be more robust.
How to specify the Laifual Drive AC high-voltage joint modules
Send these with your enquiry and an engineer can confirm the right AC high-voltage joint modules variant or an equivalent:
- Rated and peak output torque (Nm)
- Output speed (rpm)
- Ratio (:1)
- Hollow shaft diameter (mm)
- Feedback: motor-side and output-side encoders
- Brake and integrated drive options
- Supply voltage and interface
Common mistakes to avoid
- Exceeding momentary torque in a collision
- Ignoring output bearing moment load
- Mismatching drive and encoder interface
- Forgetting heat in continuous duty
Laifual Drive AC high-voltage joint modules: frequently asked questions
Can you help replace Laifual Drive AC high-voltage joint modules or source the original?
Send the full model code, quantity and required date. Our engineers can check original-part availability and assess suitable alternatives, including supply-network options where appropriate. We confirm compatibility and any changes needed before recommending a replacement.
What is the Laifual Drive AC high-voltage joint modules?
Harmonic-geared joint modules for 220 V AC external servo drives, from M70 to M190 (70–190 mm diameter), ratios 51–121, with 17-bit or 23-bit single-turn plus 16-bit multi-turn encoders over BiSS-C or Tamagawa and optional brake. Published series figures include outer diameter 70 mm, outer diameter 190 mm, ratio 51:1, ratio 121:1. It is made by Zhejiang Laifual Harmonic Drive Co., Ltd. (HKEX: 03952); Specify Motion can help source it or propose an equivalent.
Who makes the Laifual Drive AC high-voltage joint modules?
The Laifual Drive AC high-voltage joint modules is made by Laifual Drive (Zhejiang Laifual Harmonic Drive Co., Ltd. (HKEX: 03952)) and is listed here for engineers comparing options. Specify Motion is not affiliated with Zhejiang Laifual Harmonic Drive Co., Ltd. (HKEX: 03952); brand names are used only to identify the product.
What is the outer diameter of the Laifual Drive AC high-voltage joint modules?
The published series minimum outer diameter is 70 mm. Individual models and sizes in the AC high-voltage joint modules range vary, so check the exact variant against your duty cycle, mounting and environment, or ask our engineers to confirm the right size for you.
Is there an alternative to the Laifual Drive AC high-voltage joint modules?
We can assess suitable replacement options. On published figures, Motion Control Products MAH and Motion Control Products MAT are options to assess from our supply network. An engineer confirms the fit against your application before recommending anything.
What is the benefit of dual encoders on a harmonic actuator?
A motor-side encoder controls the motor, while an output-side encoder measures the joint position directly after the gear. This compensates for gear deflection and gives true absolute output position at power-up. Dual encoders improve accuracy and support safety and collision detection.
Can a harmonic actuator include its own drive?
Yes, some versions integrate the servo drive and communicate over EtherCAT, CANopen or similar networks. This reduces cabinet space and wiring. Other versions connect to a separate servo drive. Choose by machine architecture, cabinet space and the safety functions needed, such as safe torque off or functional safety over the network.
Further reading: How to select a harmonic actuator · Harmonic vs planetary vs cycloidal · Gearboxes and harmonic drives
Other harmonic actuator series
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