The Baumüller b maXX 4400 series modular servo drive inverter, type designation BM4421-SI1-21200-03-E80, engineered and manufactured by Baumüller Nürnberg GmbH (Germany), represents world-class dynamic motion control technology designed to drive both permanent-magnet AC synchronous servo motors (such as Baumüller DSC, DSD, and DSP series) and three-phase asynchronous motors (Baumüller DA series) with outstanding dynamic responsiveness and precision.

Understanding the "Without Cards" Configuration:
- The BM4421-SI1-21200-03-E80 "Without cards" specification designates a fully integrated base power and inverter chassis consisting of the main AC line rectifier, heavy-duty DC-link filter capacitors, high-efficiency IGBT power output stage, dynamic braking chopper transistor, STO safety logic, and standard internal air-cooling fans.
- Modular Plug-In Architecture: The chassis features open standard expansion slots (Slots A, B, C, D, E, F, etc.). This makes it the ideal, cost-effective replacement unit (spare part) for operating industrial plants. When an existing unit in production experiences a hardware failure, plant technicians can seamlessly migrate the existing functional plug-in modules (such as b maXX-drivePLC cards, EtherCAT/PROFINET/CANopen fieldbus communication cards, and Resolver/EnDat/Hiperface encoder feedback cards) into the new BM4421 base chassis without re-licensing software or purchasing duplicate option cards.

Key Engineering Features & Operational Advantages:
- Compact Size 2 Mechanical Architecture: Designed in an optimized Size 2 book-style housing, enabling high packaging density within the control cabinet, saving valuable cabinet floor space, and optimizing convective airflow.
- Detailed Type Key Breakdown:
  + BM4421: b maXX 4400 series modular converter, frame size 2, rated for mid-capacity dynamic motion axes.
  + S: Standard forced air cooling utilizing integrated high-reliability internal fans.
  + I: Inverter module incorporating an integrated mains rectifier and intermediate DC bus circuit.
  + 1: Integrated Safe Torque Off (STO) hardware safety function complying with EN ISO 13849-1 (PL d) and IEC 61508 (SIL 2), providing safe motor de-energization without costly external motor contactors.
  + 21200: 3-phase 400V - 480V AC nominal mains input, integrated internal braking chopper transistor, internal DC-link capacitance, and standard base hardware.
  + -03: Generation 03 hardware release with advanced digital signal processing for precise vector current control.
  + -E80: Specialized conformal PCB coating (Varnish Coated), providing exceptional protection against industrial airborne dust, humidity, and corrosive chemical vapors.
- Superior Dynamic Control Performance: Features ultra-fast current and speed control loops, advanced load inertia compensation algorithms, and anti-resonance digital filters, delivering smooth low-speed rotation and instantaneous acceleration during rapid cycle reversals.
- Comprehensive Industrial Communication Flexibility: Ready to interface with virtually any major industrial network via modular plug-in cards, including EtherCAT, PROFINET IRT, Ethernet/IP, CANopen, PROFIBUS-DP, SERCOS III, or drive-based automation via the b maXX-drivePLC module (100 μs cycle time).

Typical Industrial Applications:
- Commercial web printing: Continuous-feed gravure, multi-color flexographic printing presses, and high-speed rotary die cutters.
- Packaging & converting: Automated form-fill-seal machines (VFFS/HFFS), pallet stretch wrappers, and high-speed rotary label applicators.
- Plastics & rubber processing: Electric injection molding machines, PET blow molding machines, and film extrusion equipment.
- CNC machine tools and automated metal forming: Auxiliary feed drives, rotary indexing tables, tool turrets, and precision wire-bending machines.
- Textile manufacturing, synthetic yarn spinning, and continuous-tension winding carousels.

• Manufacturer: Baumüller (Baumüller Nürnberg GmbH)
• Country of Origin: Germany
• Product Series: b maXX 4400 Modular Servo Converter / Inverter Series
• Full Model Code: BM4421-SI1-21200-03-E80 (without cards)
• Delivery Scope: Base drive inverter unit (supplied without plug-in controller, encoder, or fieldbus cards)
• Housing Frame Size: Size 2 (Dimensions approx. 450 x 125 x 200 mm)
• Mains Supply Input Voltage: 3-Phase 400V - 480V AC ±10%, 50/60 Hz
• Nominal Intermediate DC Link Voltage: ~ 540V - 650V DC
• Recommended Motor Power Range: Up to 7.5 kW - 11 kW (depending on load duty cycle and PWM switching frequency)
• Rated Continuous Output Current (In): 10 A - 16 A (at nominal switching frequency)
• Maximum Peak Output Current (Imax): Up to 20 A - 32 A (short-term overload)
• PWM Switching Frequency: Configurable 4 kHz / 8 kHz
• Braking Chopper: Integrated dynamic braking chopper transistor; supports external dynamic braking resistor
• Integrated Functional Safety: Safe Torque Off (STO) certified to SIL 2 (IEC 61508) and PL d (EN ISO 13849-1)
• Cooling Method: Standard forced air cooling with internal fan (Code S)
• Modular Option Slots: Accommodates standard b maXX 4400 plug-in modules:
  - Industrial Fieldbus Modules: EtherCAT, PROFINET, CANopen, PROFIBUS-DP, Ethernet/IP, SERCOS
  - Encoder Feedback Interfaces: Resolver, SinCos, EnDat 2.1/2.2, Hiperface, SSI, Incremental
  - Embedded Controller: b maXX-drivePLC
  - Digital and Analog I/O Expansion Cards
• Ingress Protection Rating: IP20 (Cabinet installation)
• Printed Circuit Board Protection: E80 Conformal Varnish Coating (Protects against industrial moisture, dust, and aggressive vapors)
• Operating Ambient Temperature: 0°C to +40°C (up to +55°C with appropriate current derating)
• Net Device Weight: Approx. 8.5 kg - 11.5 kg
• Compliance & Standards: CE, UL/cURus Listed, RoHS, EMC Industrial Directives.