Digital guide
You are here:
Kollmorgen S74801-NA
Product Series: S700 Series — High-Performance AC Servo Motors
Product Overview:
The S74801-NA is an AC servo motor from Kollmorgen’s S700 family. The “748” denotes a larger frame size compared to the S7120, providing significantly higher torque and power output. The option string “NA” indicates: N = No holding brake, A = No shaft seal. This configuration is intended for horizontal-axis applications where a brake is unnecessary and environmental sealing is managed externally.
Detailed content
Key Specifications:
| Parameter | Value |
|---|---|
| Frame Size | S748 (approximately 180 mm flange) |
| Continuous Torque (Rated) | 23.9 Nm (2115 in-lb) |
| Peak Torque | 71.7 Nm (6346 in-lb) |
| Rated Speed | 2500 RPM |
| Max Speed | 3500 RPM |
| Rated Power (Continuous) | 6.3 kW |
| Peak Power | 18.9 kW |
| Stator Lamination | Standard (implied, no HD suffix) |
| Cooling Method | Conduction (no fan) |
| Shaft Seal | None (A option) |
| Brake (Holding Brake) | None (N option) |
| Voltage Rating | 400–480 VAC (three-phase) |
| Encoder Type | Absolute multi-turn, 128 sine/cosine periods |
| Encoder Resolution | 131,072 counts/rev (17-bit) |
| IP Rating | IP65 (with connector) |
Construction & Materials:
- Stator: Silicon steel laminations, Class H insulation, VPI processed
- Rotor: NdFeB permanent magnets, carbon fiber retaining sleeve
- Shaft: Hardened stainless steel, 28 mm diameter, keyway standard
- Housing: Cast aluminum alloy, natural finish
- Bearings: Deep-groove ball bearings, sealed, L10 life > 20,000 hours
Performance Parameters:
| Parameter | Value |
|---|---|
| Torque Constant (Kt) | 0.96 Nm/A |
| Back-EMF Constant (Ke) | 96.0 V/krpm |
| Phase Resistance (25°C) | 0.18 Ω (phase-to-phase) |
| Phase Inductance | 2.1 mH (phase-to-phase) |
| Rotor Inertia | 0.0028 kg·m² |
| Mechanical Time Constant (τm) | 12.5 ms |
| Electrical Time Constant (τe) | 11.7 ms |
| Max Continuous Current (RMS) | 28 A |
| Peak Current (10 sec) | 84 A |
| Motor Weight | Approximately 14.5 kg (32.0 lb) |
Advantages:
- High continuous torque (23.9 Nm) — handles heavy inertial loads without gearbox
- No brake configuration — reduces rotating mass, improves dynamic response
- Robust construction — 180 mm flange, rated for demanding industrial duty cycles
- Wide constant-torque speed range — 0 to 2500 RPM at full torque
Applicable Industries:
- Heavy Machinery — press drives, injection molding clamp units
- Metal Forming — roll drives, stamping press servo retrofits
- Pulp & Paper — calender rolls, winder drives
- Mining & Aggregate — conveyor head drives, crusher feeders
- Printing (Large Format) — main drive for wide-web presses
Installation Requirements:
- 4-bolt flange mounting per S700 dimensional standard, bolt size M10 × 1.5
- Shaft coupling: rigid or flexible coupling rated for minimum 50 Nm
- Thermal path: conduction-cooled — mount to heat sink or use forced air, target thermal resistance ≤ 0.3 °C/W
- Wiring: direct lead termination (no connector per NA) — use Kollmorgen-approved cable glands
