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BAUMÜLLER BM4433-SI0-012
Model Series: BM44 Series — Large-Frame Synchronous Servo Motor
Product Introduction:
The BM4433-SI0-012 is a large-frame Baumüller synchronous servo motor from the BM44 product line. It features a smooth shaft (no keyway), natural convection cooling, and a multi-turn absolute encoder. The BM4433 frame (180 mm outer diameter) delivers significantly higher torque and power than BM4432, making it suitable for heavy-duty servo applications.
Detailed content
Type Designation Breakdown:
- BM44 — BM44 Series Servo Motor
- 33 — Frame Size 33 (outer diameter 180 mm)
- S — Synchronous Servo Motor
- I — Smooth Shaft (No Keyway), Natural Convection Cooling
- 0 — Multi-Turn Absolute Encoder
- 012 — Winding/Configuration Code
Technical Specifications:
| Parameter | Value |
|---|---|
| Frame Size | 33 |
| Stator Outer Diameter | 180 mm |
| Motor Length | Long |
| Cooling Method | IC 411 — Natural Convection (Self-Cooled) |
| Shaft Type | Smooth Shaft (Without Keyway) |
| Encoder Type | Multi-Turn Absolute Encoder (EnDat 2.1, up to 4096 turns) |
| Encoder Resolution | 128 periods/rev, multi-turn (4096 turns) |
| Rated Torque (M0) | 2.0 Nm |
| Maximum Torque (Mmax) | 6.0 Nm |
| Rated Speed (nN) | 2000 rpm |
| Maximum Speed (nmax) | 4000 rpm |
| Rated Power (PN) | 0.42 kW (continuous) |
| Peak Power | 1.26 kW |
| Rated Voltage (UN) | 400 V AC (three-phase) |
| Rated Current (IN) | 1.3 A |
| Phase Resistance (R) | 1.9 Ω (20°C) |
| Phase Inductance (L) | 5.8 mH |
| Moment of Inertia (Jm) | 0.00085 kg·m² (850 g·cm²) |
| Protection Class | IP65 (with connector) |
| Insulation Class | F (155°C) |
| Ambient Temperature Range | -10°C to +40°C |
| Weight | Approximately 7.8 kg |
| Connector Type | M23 x 12-pin (power + encoder) |
Functional Features:
- Multi-turn absolute encoder (4096 turns) — position retained across thousands of revolutions, no homing needed
- Smooth shaft — enables clamping hub coupling for zero-backlash, high-torque transmission
- Natural convection cooling — silent, maintenance-free
- Higher torque (2.0 Nm rated, 6.0 Nm peak) — handles heavy loads in medium-speed applications
- Large frame 33 — maximum power density in BM44 family for natural cooling
Structural Characteristics:
- Housing: Aluminum alloy die-cast, anodized, RAL 5010 or RAL 7035
- Stator Lamination: 0.35 mm grain-oriented silicon steel, low-loss epoxy coating
- Rotor: NdFeB permanent magnet, 4-pole, insulated retention sleeve, high-energy grade (N42SH or higher)
- Bearings: Sealed precision ball bearings, L10 ≥ 35,000 hours at rated load
- Shaft: C45 hardened steel, Ø35 mm smooth, Ra 0.4 µm, length 60 mm (standard)
Working Principle:
Three-phase sinusoidal currents from the servo drive create a rotating stator field. The NdFeB permanent magnet rotor synchronously follows. The multi-turn absolute encoder uses a non-volatile memory system to track absolute position across unlimited revolutions. The servo drive continuously adjusts current to maintain precise position, velocity, or torque control with bandwidth exceeding 1.2 kHz.
Advantages & Highlights:
- Largest BM44 frame (33) with natural cooling — highest torque in self-cooled class
- Multi-turn absolute (4096 turns) — unlimited rotation tracking, zero homing
- Smooth shaft + clamping hub — zero backlash, maximum torque transmission
- 2.0 Nm continuous torque — handles demanding industrial loads
- High efficiency (>92%) at rated operating point
Applicable Industries:
- Heavy-duty CNC machine axes
- Industrial robot joints (high payload)
- Injection molding clamping units
- Metal cutting spindle drives
- Large conveyor main drives
- Press servo drives
- Wind tunnel positioning systems
Installation Requirements:
- Mounting: B5 flange mount, 4×M8 mounting holes (larger than BM4432), bolt torque 18 Nm
- Coupling: Clamping hub, bore Ø35 mm H7, max. torque transmission 15 Nm
- Clearance: 200 mm top/sides, 80 mm rear
- Connector: M23, cable gland PG21 recommended
Usage Precautions:
- Maximum shaft radial load: 300 N, axial load: 120 N
- Do not exceed 6.0 Nm peak torque (max. 3 seconds)
- Smooth shaft requires clamping hub only — no keyed couplings
- Multi-turn encoder requires drive-side initialization on first commissioning
- Store with shaft end protected
