Harmonic actuator
Harmonic Drive SHA-SG hollow-shaft servo actuators
A hollow-shaft servo actuator built on SHG high-torque gearing with a 17-bit absolute encoder option, offered from small to large robot-joint sizes.
Key specifications
| Rated torque (max) | 1,236 Nm |
|---|---|
| Peak torque (max) | 3,419 Nm |
| Speed (max) | 509.1 rpm |
| Supply | 200 VAC (100 VAC size 25; 20–90 VDC sizes 20/25/32) |
| Ratio | 11–161:1 |
| Sizes | 20, 25, 32, 40, 45, 58, 65 |
Summarised in our own words from Harmonic Drive SE / Harmonic Drive LLC's published data; series maxima, individual models vary. Last checked 2026-10-29. Source 1
Notes on this data
Ratios are 11 (sizes 25/32 only), 51, 81, 101, 121 and 161. Maxima are for SHA-65-161: max torque 3419 Nm, rated (continuous) torque 1236 Nm. 509.1 rpm is for size 25 at 11:1. Encoders are 17-bit absolute or incremental. One-way accuracy is 40–120 arcsec. The page gives no bore, IP or backlash figure.
Specify Motion is not affiliated with Harmonic Drive SE / Harmonic Drive LLC. Harmonic Drive and SHA-SG hollow-shaft servo actuators are used only to identify the product. Comparisons use published figures; always confirm against the current datasheet.
Typical applications
Alternatives that meet or exceed these figures
Engineers often come to us with a Harmonic Drive part number and leave with an alternative that is easier to source, quicker to deliver or a better fit for the machine. These 3 series from our supply network are the closest match on published figures.
High-rigidity Wanshsin inline planetary with three backlash classes down to super-precision, for machine tools, automation and AGVs.
| Published maximum | SHA-SG hollow-shaft servo actuators | WSH |
|---|---|---|
| Peak torque | 3,419 Nm | 7,200 Nm meets or exceeds |
| Rated torque | 1,236 Nm | 2,400 Nm meets or exceeds |
| Speed | 509.1 rpm | 6,000 rpm meets or exceeds |
Right-angle version of the high-rigidity WSH, with a spiral bevel stage and ratios up to 200:1.
| Published maximum | SHA-SG hollow-shaft servo actuators | WSHR |
|---|---|---|
| Peak torque | 3,419 Nm | 4,200 Nm meets or exceeds |
| Rated torque | 1,236 Nm | 1,400 Nm meets or exceeds |
| Speed | 509.1 rpm | 6,000 rpm meets or exceeds |
Wanshsin inline planetary designed for high radial loads, offered in three precision classes.
| Published maximum | SHA-SG hollow-shaft servo actuators | WTH |
|---|---|---|
| Peak torque | 3,419 Nm | 6,150 Nm meets or exceeds |
| Rated torque | 1,236 Nm | 2,050 Nm meets or exceeds |
| Speed | 509.1 rpm | 6,000 rpm meets or exceeds |
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.
Other harmonic actuator series
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