Harmonic Drive FHA-C, PR and H Hollow-Shaft Actuators Review: Specs, Price and Applications
Updated: 4 days ago
Harmonic Drive FHA-C combines strain-wave reduction, a brushless servomotor, output support and motor feedback in a low-profile hollow-shaft actuator. The standard, PR and high-voltage H configurations have different ordering options and performance data. These versions use an external servo drive; the actuator’s hollow bore and gear ratio do not establish the drive interface or a complete safety-rated robot joint.
Quick Verdict
Consider FHA-C for an OEM rotary axis that benefits from a central passage and a matched motor/reducer assembly. Choose standard, PR or H by the actual winding, feedback, positioning duty and environment. Do not transfer H-series continuous torque, a PR repeatability figure or an optional IP65 rating to every FHA-C actuator.
Harmonic Drive FHA-C, PR and H Hollow-Shaft Actuators at a Glance
Specification | Details |
Frame families | 17 / 25 / 32 / 40; external servo drive required |
Standard and PR ratio menu | 50 / 80 / 100 / 120 / 160 in current ordering tables; exact configuration applies |
H ratio menu | 50 / 100 / 160 in the high-voltage ordering table |
Standard / PR motor feedback | US250 or E250 incremental encoder options; 2500 pulses per motor revolution with different wiring arrangements |
H winding and feedback | H denotes 680 VDC winding/bus class for a matched servo system; EnDat and HIPERFACE options depend on full code |
Protection choice | H ordering table: standard IP44, P option IP65; H alone does not identify an IP65 unit |
PR size 17, ratio 100 example | 57 Nm maximum torque; 48 rpm maximum output speed; 40 arcsec one-way accuracy; ±5 arcsec one-way and 30 arcsec bidirectional repeatability entries |
H size 17, ratio 50 example | 15 Nm continuous; 39 Nm maximum; 96 rpm maximum output speed |
H size 40, ratio 160 example | 400 Nm continuous; 823 Nm maximum; 22 rpm maximum output speed |
Motor-derived quadrature scale | Standard/PR tables: 500000 to 1600000 output-equivalent counts/revolution across ratios 50–160; not independent output measurement |
Brake and cable options | Full model code selects brake, feedback, cable exit and other supported options |
Price | Request a quote for exact actuator, compatible drive, feedback, brake, cables and protection |
Design and Engineering Assessment
The hollow center can simplify routing of tubing, cables or an optical path through the rotary axis. It does not provide unlimited cable rotation. Define allowable travel and any rotary union or slip-ring arrangement separately, and verify the clear bore for the actual frame and selected options.
The actuator integrates a motor and reducer, but its servo amplifier remains external. A drive must match the winding, feedback protocol, current convention and commutation arrangement. Names of communication networks associated with a compatible drive should not be copied onto the actuator as if every FHA-C contains those interfaces.
The PR option targets positioning performance, but accuracy and repeatability remain distinct. At size 17 ratio 100, the current PR table lists 40 arcsec one-way positioning accuracy, ±5 arcsec one-way repeatability and a 30 arcsec bidirectional repeatability entry. A mechanism that reverses under load should not use the one-way repeatability number as its full positioning-error budget.
The H winding has its own continuous-torque data. For example, size 40 ratio 160 is listed at 400 Nm continuous and 823 Nm maximum, with 22 rpm maximum output speed. Those values cannot be combined with the faster output speed of a lower ratio or assumed to apply to a standard or PR winding. Build the required torque-speed cycle from the exact table column.
Standard FHA-C and PR: select the positioning configuration
Current standard and PR ordering tables include ratios 50, 80, 100, 120 and 160 in the four size families. Older announcements describing only three ratios do not define the full current menu. The selected ordering code and its own performance row remain the design authority.
US250 and E250 are incremental motor-feedback options with different wiring arrangements. The published quadrature scale is derived through the reduction ratio: 2500 motor pulses counted on four edges and multiplied by ratio 100 gives 1000000 output-equivalent counts per revolution. This calculation is not evidence of a separate load encoder or corresponding absolute accuracy.
H variant: high-voltage winding, feedback and protection
The H table identifies a 680 VDC winding/bus class and EnDat or HIPERFACE feedback selections. The manufacturer describes this as a 480 VAC servo-system class. It is not an instruction to connect the bare actuator directly to mains; use a matched amplifier and the exact motor electrical and feedback configuration.
The P option supplies IP65 in the H ordering table, while the standard entry is IP44. Specify the complete protection code, connectors and cable arrangement. A protection label does not by itself establish compatibility with every wash-down chemical, pressure or installation condition.
Brake, mounting and output support
The B option denotes a brake in the H ordering code. It changes the package and wiring: quoted examples have different mass and axial dimensions with a brake. Confirm the selected drawing, whether the brake is suitable for the required holding duty, and the actual machine stopping sequence.
Calculate output bearing radial, axial and moment loads together with motor/reducer torque duty. A high output torque does not establish an unlimited overhung load. The hollow-shaft architecture also requires a mounting and cable layout that maintains access and avoids unintended loads on connectors or the output structure.
Current, speed and thermal commissioning
Motor-current tables use RMS values. Keep phase-current ratings distinct from DC input-supply current and drive peak-amplitude conventions. Check the selected actuator’s winding, thermal path and repeatable duty rather than assuming that a maximum torque can be held indefinitely.
Maximum speed is a separate limit from continuous torque. Include acceleration, process load, deceleration and energized holding in the cycle. Verify bus behavior and regenerated energy at the matched drive, particularly where the load can externally turn the axis.
Feedback, referencing and fault behavior
Incremental standard/PR feedback needs an appropriate referencing strategy after relevant power interruptions. H feedback can be single-turn or a specified multiturn option, depending on code. The presence of an absolute motor encoder does not automatically establish an unambiguous load position through every machine state.
Define following-error limits, loss-of-command behavior and any required brake sequence. Commission direction, feedback interpretation and travel limits at reduced speed before testing the real load. The actuator component and a drive enable input are not a substitute for the machine’s required safety functions.
Alternatives and full-system quotation
Compare standard, PR and H on the actual motion and environment requirements. A smaller FHA-C Mini or an actuator with an integrated drive has a different physical and control scope, while a direct-drive motor removes reduction and changes torque, inertia and feedback selection.
Request the complete actuator code with matched drive, feedback cables, brake wiring, mounting and control scope. Keep the accepted parameters and exact drawing with the machine documentation so a replacement restores the same electrical and mechanical configuration.
Applications and Selection
Consider FHA-C for robot mechanisms, machine-tool axes, packaging equipment and related OEM rotary motion where the selected hollow-shaft actuator and external drive fit the load and environment. Suitability depends on the exact model and complete machine integration, including any protection or holding requirements.
For Harmonic Drive FHA-C, PR and H Hollow-Shaft Actuators, define the actual machine duty before selecting an ordering configuration. Include the required operating point, available installation space, environment and control interfaces. The specification table describes the product or family; the surrounding machine determines which of those features matters for the intended job.
Price and Value
Price: Request a quote for the exact configuration. Compare the product, compatible control equipment, required mechanical parts, cabling and commissioning as one installed system. A component price alone does not represent the cost of a working automation axis.
Evaluate an alternative against the same duty and acceptance criteria. Match the continuous operating requirement first, then compare transient capability, feedback, mechanical fit and support. This avoids choosing between superficially similar products whose ratings describe different operating conditions.
Pros and Cons
Advantages
Integrates matched motor, strain-wave reducer and output support
Hollow-shaft layout supports central service routing
PR and H variants address different positioning and electrical requirements
Multiple ratios, feedback and brake choices support a defined ordering configuration
Limitations
External drive and exact feedback compatibility must be specified
IP65 is an ordering choice in the H table rather than a universal family property
Motor-derived count scale is not load-position accuracy
Torque, speed and repeatability maxima belong to specific variants and duties
Who Should Consider Harmonic Drive FHA-C, PR and H Hollow-Shaft Actuators?
Consider this family when an OEM axis needs a low-profile motor/reducer assembly with a central passage and can use an external compatible servo drive. Define the required one-way and bidirectional positioning result, continuous duty, feedback and environment before selecting the variant.
Harmonic Drive FHA-C, PR and H Hollow-Shaft Actuators FAQ
Does standard FHA-C include the servo drive?
No. The reviewed standard, PR and H configurations use an external matched servo amplifier. The selected drive supplies the host communication interface and must support the actuator winding and feedback.
How many reduction ratios are available?
Current standard and PR menus list 50, 80, 100, 120 and 160, while the H ordering table lists 50, 100 and 160. Confirm availability for the complete selected reference rather than copying an older family announcement.
Does H automatically mean IP65?
No. The H ordering table lists IP44 as standard and P as the IP65 option. Specify protection, connectors and cable arrangement with the full code.
Can the H actuator be connected directly to 480 V mains?
Use a matched servo amplifier and the exact electrical documentation. The H code identifies the high-voltage winding/bus class in a servo system, not an unrestricted direct-mains connection.
Is one-way repeatability the same as bidirectional accuracy?
No. For PR size 17 ratio 100, the current table separates 40 arcsec one-way accuracy, ±5 arcsec one-way repeatability and 30 arcsec bidirectional repeatability. Match the required measurement and motion direction.
Does one million output-equivalent counts mean an output encoder is included?
No. In standard/PR tables that scale is derived from motor quadrature counts and reduction ratio. It does not independently measure load-side deflection or establish the same angular accuracy.
Can the maximum torque be used continuously?
No. Use the selected continuous-duty rating and thermal conditions. For H size 40 ratio 160, the table separates 400 Nm continuous from 823 Nm maximum.
What is the price?
Request a quote for the exact actuator, ratio, winding, encoder, brake, protection and cable choices. Include the matched drive, controller and mounting requirements for the working axis.
Prices are indicative and may change. Confirm the final configuration, commercial terms and delivery schedule before ordering.
