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BAUMÜLLER BM4433-SI1-012
Model Series: BM44 Series — Large-Frame Synchronous Servo Motor
Product Introduction:
The BM4433-SI1-012 is a large-frame Baumüller synchronous servo motor with smooth shaft, natural convection cooling, and a single-turn absolute encoder. The BM4433 frame (180 mm) provides the highest torque and power in the BM44 naturally-cooled family, while the single-turn encoder offers fast position feedback for applications limited to one revolution per axis.
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
- 1 — Single-Turn Absolute Encoder
- 012 — Winding/Configuration Code
Technical Specifications:
| Parameter | Value |
|---|---|
| Frame Size | 33 |
| Stator Outer Diameter | 180 mm |
| Cooling Method | IC 411 — Natural Convection (Self-Cooled) |
| Shaft Type | Smooth Shaft (Without Keyway) |
| Encoder Type | Single-Turn Absolute Encoder (EnDat 2.1, 14-bit) |
| Encoder Resolution | 128 periods/rev (16,384 counts/rev, single-turn) |
| Rated Torque (M0) | 1.8 Nm |
| Maximum Torque (Mmax) | 5.4 Nm |
| Rated Speed (nN) | 2500 rpm |
| Maximum Speed (nmax) | 4500 rpm |
| Rated Power (PN) | 0.47 kW (continuous) |
| Peak Power | 1.41 kW |
| Rated Voltage (UN) | 400 V AC (three-phase) |
| Rated Current (IN) | 1.4 A |
| Phase Resistance (R) | 2.0 Ω (20°C) |
| Phase Inductance (L) | 6.0 mH |
| Moment of Inertia (Jm) | 0.00080 kg·m² (800 g·cm²) |
| Protection Class | IP65 (with connector) |
| Insulation Class | F (155°C) |
| Ambient Temperature Range | -10°C to +40°C |
| Weight | Approximately 7.5 kg |
| Connector Type | M23 x 12-pin (power + encoder) |
Functional Features:
- Single-turn absolute encoder (14-bit, 16,384 counts/rev) — high-resolution position feedback within 0°-360°
- Smooth shaft — clamping hub coupling for zero-backlash connection
- Natural convection cooling — silent, zero-maintenance operation
- Large frame 33 — 1.8 Nm rated torque, 5.4 Nm peak — highest in BM44 self-cooled class
- High speed capability up to 4500 rpm with constant torque to rated speed
Structural Characteristics:
- Housing: Aluminum alloy die-cast, anodized finish
- Stator: 0.35 mm grain-oriented silicon steel, epoxy-coated laminations
- Rotor: NdFeB permanent magnet, 4-pole, N42SH grade, insulated retention sleeve
- Bearings: Sealed precision ball bearings, L10 ≥ 35,000 hours
- Shaft: C45 hardened steel, Ø35 mm smooth, Ra 0.4 µm, length 60 mm
Working Principle:
Three-phase AC from servo drive creates rotating stator field. NdFeB rotor locks synchronously. Single-turn absolute encoder delivers 14-bit absolute position within one revolution. Servo drive performs closed-loop control with bandwidth >1.2 kHz, achieving precise position, velocity, and torque regulation.
Advantages & Highlights:
- Largest naturally-cooled BM44 motor (1.8 Nm continuous)
- Single-turn absolute (16,384 counts/rev) — highest resolution single-turn in BM44 series
- Smooth shaft — zero backlash with clamping hub
- Wide speed range 0-4500 rpm
- IP65 rated — suitable for harsh industrial environments
Applicable Industries:
- Heavy-duty CNC axes (X/Y/Z)
- High-payload robot joints
- Servo press drives
- Large indexing tables
- Main spindle drives (medium speed)
- Heavy conveyor systems
Installation Requirements:
- Mounting: B5 flange, 4×M8 holes, bolt torque 18 Nm
- Coupling: Clamping hub, Ø35 mm H7, max. torque 15 Nm
- Clearance: 200 mm top/sides, 80 mm rear
- Connector: M23, PG21 cable gland
Usage Precautions:
- Maximum radial shaft load: 300 N, axial: 120 N
- Peak torque 5.4 Nm max. 3 seconds — do not sustain
- Smooth shaft only — no keyed couplings
- Encoder: single-turn — requires homing if multi-revolution axis is needed
