Three motor lengths
Select the motor length and holding torque that best match the axis load and available installation envelope.
SP28 28 mm Hybrid Rotary Stepper Motor
Hybrid Rotary Stepper Motor
The SP28 28 mm hybrid rotary stepper motor provides 0.06–0.14 N·m holding torque across three compact motor lengths, with optional encoder, power-off brake and 28 mm planetary gearbox configurations.
Positioning accuracy
High torsional rigidity and constant torsional backlash over the entire gearbox service life ensure consistently high performance
Compactness
High torque density thanks to high performance and short design
Low maintenance
Highest quality standards for a long service life and extended maintenance intervals
Technical data
Compact hybrid stepper platform
28 mm hybrid rotary stepper motors for precise positioning
The SP28 series combines a compact 28 mm frame with three motor lengths, 0.06–0.14 N·m holding torque and 1 A rated current. Encoder, power-off brake and planetary gearbox options support flexible machine integration.
Configurable feedback
EK1 and EK7 incremental encoder options support single-ended or differential outputs across a broad resolution range.
Integrated options
Add a 24 V power-off brake or a multi-stage planetary gearbox to simplify holding and transmission requirements.
Engineering information
Technical data
Compare the verified motor models and optional components. The torque-speed curves were measured with a constant-current drive at 24 VDC using 2-phase excitation.
Model selection
Motor specification matrix
| Model | Rated current | Resistance | Inductance | Holding torque | Rotor inertia | Motor length | Weight |
|---|---|---|---|---|---|---|---|
| 11H2033 | 1 A | 2.1 Ω | 1.2 mH | 0.06 N·m | 9 g·cm² | 33.35 mm | 110 g |
| 11H2045 | 1 A | 4.1 Ω | 3.2 mH | 0.10 N·m | 13 g·cm² | 45 mm | 200 g |
| 11H2052 | 1 A | 4.7 Ω | 3.9 mH | 0.14 N·m | 18 g·cm² | 52 mm | 280 g |
General data
Common electrical and mechanical data
| Specification | Value |
|---|---|
| Frame size | 28 mm |
| Step angle | 1.8° ±5% |
| Resistance tolerance | ±10% at 20°C |
| Inductance tolerance | ±20% at 1 kHz |
| Insulation class | Class B |
| Duty cycle | S1 |
| Dielectric strength | 500 VAC / 1 kHz / 1 mA / 1 s |
| Insulation resistance | 100 MΩ at 500 VDC |
| End cover | Die-cast aluminum |
| Bearing | Deep-groove ball bearing |
| Permanent magnet | Sintered NdFeB |
| Shaft | Stainless steel |
| Lead wire | UL 3265, 26 AWG |
Shaft loading
Allowable radial load
| Load point from mounting face | Allowable radial load |
|---|---|
| 5 mm | 50 N |
| 10 mm | 35 N |
| 15 mm | 25 N |
| 20 mm | 20 N |
Feedback options
Incremental encoder selection
| Encoder | Output | Resolution options |
|---|---|---|
| EK1 | Single-ended or differential | 100 / 108 / 120 / 125 / 128 / 200 / 250 / 256 / 300 / 360 / 400 / 500 / 512 / 720 / 800 / 1000 PPR |
| EK7 | Single-ended or differential | 1000 or 2000 PPR |
Holding brake
Optional power-off brake
| Specification | Value |
|---|---|
| Rated voltage | 24 VDC ±5% |
| Coil resistance | 143.7 Ω ±10% |
| Power | 5.5 W |
| Static torque | >0.3 N·m |
| Insulation class | Class B |
| Insulation resistance | >100 MΩ at 500 VDC |
| Dielectric strength | 1000 VAC / 1 s |
| Engage / release time | 50 ms / 50 ms |
| Backlash | 1° |
| Emergency braking | 200 cycles |
| Mechanical life | 2,000,000 cycles |
| Noise | <60 dB |
Precision gearing
Optional planetary gearbox
| Ratio | Stages | Rated torque | Peak torque | Efficiency | Gearbox length | Weight |
|---|---|---|---|---|---|---|
| 3.3 / 4.6 | 1 | 0.5 N·m | 1.5 N·m | 90% | 21.2 mm | 87 g |
| 11.2 / 15.5 / 21.5 | 2 | 1 N·m | 3 N·m | 81% | 26.9 mm | 91 g |
| 37.7 / 72 | 3 | 2.5 N·m | 7.5 N·m | 73% | 32.7 mm | 100 g |
| No-load backlash | 1° | |||||
| Housing | Metal | |||||
| Bearing | Ball bearing | |||||
System integration
Configure the motor, feedback and transmission around the axis
Choose the base motor by holding torque, current and length, then match the encoder, brake or gearbox to the control and mechanical requirements of the machine.
- Verify the required operating point against the 24 V torque-speed curves
- Select single-ended or differential encoder output to match the controller
- Confirm gearbox ratio, brake holding requirement, shaft load and installation envelope
Application fields
Compact stepper motion for automation equipment
The compact 28 mm platform fits space-constrained rotary axes that require configurable feedback, holding and transmission options.
Industrial automation
Indexing, feeding, positioning and auxiliary machine axes.
Medical and laboratory systems
Compact pumps, sample handling and instrument mechanisms.
Robotics
Grippers, rotary joints and compact positioning modules.
Precision equipment
Optical, inspection and measurement mechanisms requiring repeatable motion.
Discuss your 28 mm hybrid rotary stepper motor requirement with our engineers.
Share the load, speed, duty cycle, feedback, brake, gearbox and installation requirements for configuration support.
Contact us
Would you like to learn more about our solutions?
We would be happy to advise you—personally, competently, and tailored to your requirements.
Perfection in a new dimension
Further Information
Short delivery times available for selected product configurations.
The TP+ HIGH TORQUE enables maximum torque density and maximum torsional rigidity—ideal for demanding applications with dynamic load changes and high positioning accuracy.
alpha Advanced Line gearboxes with increased durability and food-grade lubrication available.
The TP+ for coordinated pinion-rack systems for medium to high requirements. Typical areas of application in wood, plastic, and composite processing, in machining centers, or in automation.
With cynapse® and smart services, you can unleash the full potential of your drive system: sensor data is processed, visualized, and analyzed intelligently. Find out how the combination of gearboxes with cynapse® and our Smart Services can make your digital production faster, safer, and more efficient.
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