Description
Harmonic Drive FHA-17C-50-H-C1024 | AC Servo Actuator
Dynamic Product Introduction
The FHA-17C-50-H-C1024 is a complete servo actuator rather than a gearbox that requires a separate motor. Harmonic Drive combines its precision harmonic gearing with a matched brushless AC servo motor and encoder in the FHA-C package. The output is hollow, allowing cables, tubing, or other services to pass through the center of the rotating axis.
The 50:1 reduction is the defining mechanical characteristic of this version. The FHA-C design is intended for applications where compact packaging, high reduction, precise positioning, and low backlash matter more than using a conventional motor-plus-gearbox arrangement. Harmonic Drive specifies zero backlash for the FHA-C family and transmission accuracy better than 1 arcmin in its engineering documentation.
FHA-17C-50-H-C1024
Model-Code Breakdown
The complete part number is worth preserving because every section carries engineering information:
FHA – 17C – 50 – H – C1024
- FHA — FHA-C servo actuator family
- 17C — frame/design size
- 50 — 50:1 harmonic reduction ratio
- H — high-voltage motor winding configuration
- C1024 — incremental encoder feedback
Harmonic Drive’s official ordering table lists 17C, 25C, 32C, and 40C sizes, with 50, 100, and 160 ratios in the documented FHA-C configuration.
Key Technical Specifications
- Manufacturer: Harmonic Drive
- Series: FHA-C
- Model: FHA-17C-50-H-C1024
- Actuator Type: AC servo actuator
- Mechanical Design: Hollow-shaft
- Frame Size: 17C
- Reduction Ratio: 50:1
- Motor Winding: H
- Maximum DC Bus Voltage for H Winding: 680 VDC
- Motor Feedback: C1024 incremental encoder
- Feedback Protocol: Incremental; Harmonic Drive’s ordering table lists no digital protocol for C1024
- Output: Hollow-shaft precision harmonic-drive output
- Backlash: Zero-backlash design
- Transmission Accuracy: Better than 1 arcmin
- Motor Type: Brushless AC servo motor
- Output Support: Integrated output bearing
- Safety Standard Listed by Harmonic Drive: EN 60034-1:2010
The encoder designation is especially important: C1024 is not an absolute encoder option. Harmonic Drive identifies C1024 as incremental, while M512P is multi-turn absolute EnDat and M128P is multi-turn absolute HIPERFACE.
Encoder and Drive Compatibility
The feedback specification needs to be matched to the servo drive.
Harmonic Drive’s documentation identifies as an incremental encoder. The actuator therefore needs a compatible drive and feedback interface rather than a controller expecting an absolute EnDat or HIPERFACE encoder.
This is not a cosmetic suffix. Replacing an actuator with an M512P, M128P, or another encoder configuration can change the feedback interface and commissioning requirements even if the mechanical frame and gear ratio look similar.
Harmonic Drive also publishes dedicated driver documentation. Its HA-655 documentation, for example, uses actuator codes that distinguish FHA-17C versions by reduction ratio and encoder configuration. The manual explicitly warns against connecting an actuator with a different code than the driver configuration.
Mechanical Architecture
The FHA-C is built around several functions that would otherwise have to be integrated separately:
- Brushless AC servo motor
- Harmonic reduction gearing
- Hollow output shaft
- High-capacity output bearing
- Incremental feedback
- Compact cylindrical housing
The hollow shaft is useful where cables, pneumatic lines, optical paths, or other services need to pass through the rotational center. Harmonic Drive specifically identifies this as one of the FHA-C’s principal design features.
The integrated output bearing also allows the actuator to support external loads directly, subject to the manufacturer’s specified mechanical load limits. Do not select the actuator solely from motor torque; radial, axial, moment, mounting, and duty-cycle requirements must also be checked against the engineering data for the exact installation.
Global Sourcing & Live-Test SOP
1. Inbound Verification
For FHA-17C-50-H-C1024, verify the complete type designation on the actuator label.
Check:
- FHA series marking
- 17C frame designation
- 50 reduction ratio
- H winding
- encoder
- Serial number
- Manufacturing information
- Connector condition
- Output shaft condition
- Housing and bearing condition
Do not accept a generic “FHA-17C” identification as sufficient. The portion determines the electrical and feedback configuration.
2. Mechanical Inspection
Before energizing the actuator:
- Rotate the output carefully by hand where the installation permits.
- Check for abnormal mechanical roughness.
- Inspect the hollow shaft for damage or contamination.
- Inspect mounting surfaces and locating features.
- Check connector integrity.
- Look for impact damage around the output bearing.
- Confirm that there is no evidence of forced disassembly.
A damaged output bearing or contaminated encoder connector can create problems that will not necessarily appear during a short electrical power-up.
3. Drive Compatibility Check
Match the actuator to the intended servo amplifier before applying power.
Confirm:
- Actuator frame
- 50:1 ratio
- H winding
- incremental feedback
- Correct motor current parameters
- Correct encoder configuration
- Correct commutation/setup parameters
Harmonic Drive’s own driver documentation emphasizes that the driver must be configured for the appropriate actuator code.
4. Functional Test
A proper live test should verify:
- Motor initialization
- Encoder feedback
- Correct direction
- Servo enable
- Stable low-speed rotation
- Position/velocity feedback
- Abnormal noise or vibration
- Drive fault status
- Brake operation if the specific actuator carries the optional B brake
Do not claim a full load test unless the actuator has actually been operated under an appropriate mechanical load.
5. Final Preparation
Before shipment:
- Record the complete model number.
- Photograph the nameplate.
- Record encoder and winding configuration.
- Protect all connectors.
- Prevent contamination of the hollow shaft.
- Use appropriate shock and ESD protection.
- Document whether a brake, sensor, or special cable configuration is included.
Field Engineer’s Pitfall Guide
❗ 1. Is an Incremental Encoder
This is the most important electrical distinction.
= incremental encoder.
Harmonic Drive separately identifies M512P as multi-turn absolute EnDat and M128P as multi-turn absolute HIPERFACE. Do not substitute one feedback type for another simply because the mechanical actuator appears identical.
❗ 2. H Winding Is Not the Same as the L Version
Harmonic Drive’s ordering data specifies:
- H: maximum DC bus voltage 680 VDC
- L: maximum DC bus voltage 330 VDC
That makes the winding designation a genuine drive-selection parameter. An actuator with the wrong winding configuration is not a harmless substitute.
❗ 3. Match the Servo Drive to the Actuator
A common field mistake is replacing an actuator based only on frame size and reduction ratio.
For example, two FHA-17C actuators can share the same mechanical family while having different feedback configurations. Harmonic Drive’s HA-655 documentation explicitly uses actuator codes to distinguish ratio and encoder combinations and warns against incorrect actuator/driver combinations.
Intent-Driven FAQ
What is the Harmonic Drive FHA-17C-50-H-?
It is an FHA-C hollow-shaft AC servo actuator with a 17C frame, 50:1 harmonic reduction, H motor winding, and incremental encoder.
just a harmonic gearbox?
No. It is an integrated servo actuator containing the harmonic gearing, brushless motor, output bearing, and encoder.
What is the reduction ratio?
The has a 50:1 reduction ratio.
What encoder does use?
designates an incremental encoder. Harmonic Drive does not identify a digital feedback protocol for this code in the ordering table.
Ws the mean?
It identifies the H motor winding. For the FHA-C family, Harmonic Drive specifies a maximum DC bus voltage of 680 VDC for the H winding.
Does the FHA-C have a hollow shaft?
Yes. The FHA-C is specifically designed with a hollow shaft through the center of the output. Harmonic Drive identifies this as a core feature for routing cables, tubing, or other services through the rotational axis.
Is the suitable for robotics?
The architecture is well suited to precision rotary motion applications where compact packaging and accurate positioning are required. The manufacturer’s FHA-C material identifies the family for applications using precision rotary servo motion. Actual suitability still depends on output load, speed, duty cycle, inertia, and drive compatibility.
