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Kollmorgen S7120F-NAPMNA
Product Overview:
The S7120F-NAPMNA is a hybrid stepper motor from Kollmorgen’s S7 product line, designed for open-loop and closed-loop stepper applications. The “7120” indicates a NEMA 23 frame (57 mm × 57 mm face). The suffix “F-NAPMNA” encodes: F = face mount, N = North American variant, A = winding A, P = parallel winding, M = mechanical brake, N = connector type, A = shaft variant.
Detailed content
Technical Specifications:
| Parameter | Value |
|---|---|
| Motor Type | Hybrid Stepper (2-phase, 1.8° step angle) |
| Frame Size | NEMA 23 (57 mm × 57 mm) |
| Step Angle | 1.8° (200 steps/rev) |
| Holding Torque | 2.8 Nm (395 oz-in) |
| Rated Current (per phase) | 4.2 A |
| Resistance (per phase) | 0.55 Ω |
| Inductance (per phase) | 3.8 mH |
| Rotor Inertia | ~55 g·cm² |
| Shaft Type | Dual shaft — 6.35 mm (1/4″) and 8 mm with keyway |
| Shaft Length | 25 mm (front), 20 mm (rear) |
| Enclosure Rating | IP54 (with connector) |
| Weight | ~1.2 kg |
| Operating Temperature | -20°C to +50°C |
| Brake | Electromagnetic holding brake — 2.8 Nm holding torque (powered off) |
| Feedback (optional) | Incremental encoder — 1000 lines (4000 counts/rev) |
| Encoder Output | RS-422 (A, B, Z) |
Material Composition:
- Housing: Aluminum alloy 6061-T6, black anodized
- Shaft: Hardened stainless steel 17-4PH (dual shaft)
- Magnets: Ferrite (ceramic) — hybrid stepper rotor
- Windings: Class B insulation (130°C), copper
- Bearings: Ball bearings (front and rear)
- Brake: Spring-applied, electrically released — NdFeB magnet
Structural Features:
- NEMA 23 face mount — 4 mounting holes on 57 mm bolt circle
- Dual shaft — allows pulley on one side, encoder/brake on other
- Electromagnetic brake — holds position when power is removed
- Rear-mounted M23 connector for 4-phase wiring and encoder
Working Principle:
The motor has 50 teeth on the rotor with a permanent magnet. The stator has 8 poles (4 phases). Each electrical cycle (4 steps) advances the rotor by one tooth pitch (7.2° mechanical). With 200 full steps per revolution (1.8°/step), microstepping drives can achieve up to 25,600 microsteps/rev (0.014° resolution). The brake uses a spring to clamp the shaft when de-energized.
Advantages:
- Holding brake — maintains position without power (critical for vertical axes)
- Dual shaft — flexible mechanical integration
- High holding torque for frame size — 2.8 Nm in NEMA 23
- Closed-loop capable with optional encoder — eliminates step loss
- Wide temperature range — -20°C to +50°C
Applicable Industries:
CNC routers, 3D printers, laser cutters, pick-and-place machines, medical devices, valve actuators, antenna positioners, automation equipment
Series: S7 (NEMA 23 hybrid stepper)
Installation Requirements:
- Bolt to NEMA 23 mounting pattern — 4× M5 holes on 57 mm circle
- Do not exceed 4.2 A per phase — overcurrent causes thermal damage
- Brake voltage: 24 VDC nominal — do not apply 48 V to brake coil
- Use microstepping drive for smooth motion — full-step operation causes vibration
Usage Notes:
- Always use a current-limiting (chopper) drive — never connect directly to power supply
- Brake release time: ~15 ms — account for delay in motion profiles
- Resonance at 150–300 RPM — use microstepping or mechanical damping
- Do not back-drive with power off — brake holds, but external force >2.8 Nm will overcome it
