SEW BW068-004 Detailed Product Description

SEW BW068-004 is a super-miniature high-resistance braking resistor of the SEW BW series, specially designed for 0.25–0.37kW small-power servo/variable frequency systems, used for precise braking and energy dissipation in light-load, low-speed, and micro-inertia equipment. It is suitable for use in ultra-compact electronic control cabinets and distributed micro-drive scenarios.

1. Basic Information

Product Series: BW Series Brake Resistor (Brake Resistor)

Full Model: BW068-004

Variant Model: BW068-004-T (Metal Mesh Cover, IP54 Protection)

Product Type: Wound-Resistor, Aluminum Shell Wave Heat Dissipation, Built-in Temperature Control Protection

Manufacturer: SEW-EURODRIVE (Germany)

Driver Compatibility: SEW MOVITRAC, MC07B, MOVIDRIVE B Micro Series

Application Scenarios: Micro-sized Equipment Braking, Light Load Emergency Stop, Micro-Inertia Positioning, Distributed Micro-Drive System

Protection Grade: IP20 (Standard) / IP54 (-T Type)

Cooling Method: Natural Cooling (No Forced Air Cooling Required)

2. Model Meaning Interpretation

BW: Brake Resistor (Brake Resistor) Series

068: Nominal Resistance 68Ω (Ohm)

004: Rated Power 0.4kW (400W)

3. Core Technical Parameters

1. Electrical Parameters

Rated Power (PR): 0.4kW (Continuous, 100% ED)

Peak Power (PP): 4kW (Short Time, 10s, 10% ED)

Nominal Resistance (R): 68Ω ±5%

Voltage Rating: 800V DC (Compatible with 300–600V DC Bus)

Insulation Class: F Grade (155℃)

Temperature Switch: Built-in Normally Closed 85℃ Temperature Control, Overheating Cut-off, Linked Driver Alarm

Maximum Temperature Rise: 375℃ (Resistance Wire)

Shell Temperature: ≤120℃ (Safe Contact)

2. Physical Parameters

Package: Aluminum Shell Wave Heat Dissipation (BW068-004) / Metal Mesh Cover (BW068-004-T)

Size (W×H×D): Approximately 145×95×55mm (Ultra-Compact)

Weight: Approximately 1.8kg

Installation Method: Wall-mounted, Vertical Installation

Connection Terminals: 2×M4 Screw Terminals

3. Environmental Characteristics

Operating Temperature: -25℃ ~ +45℃

Humidity: 5–95% (No Condensation)

Vibration Resistance: Industrial Grade, Compatible with Precision Instruments, Micro-Sized Automation Equipment

Life: 10,000 Hours (Full Load)

4. Functions and Advantages

1. Ultra-Micro Precise Braking

0.4kW/68Ω: Precisely Match 0.25–0.37kW Small-Power Drive System

High Resistance Characteristics: Suitable for Low Bus Voltage, Micro-Current Braking Scenarios

Peak 4kW: Satisfy Micro-Inertia, Light Load, Low-Speed Equipment's Rapid Braking

Low Inductance Design: Does Not Interfere with Servo Control, High Positioning Accuracy, No Electromagnetic Interference

2. Safe and Reliable

Dual Protection: 85℃ Temperature Switch + High Insulation Voltage Rating

Industrial Grade Material: High-Temperature Resistance Wire, Corrosion-Resistant Aluminum Shell

Long Life: Solid State Resistance, No Aging, No Maintenance Required

3. Ultra-Compact Design

Small Volume, Light Weight: Compatible with Ultra-Micro Electronic Control Cabinets, Embedded Installation

Installation Flexible: Vertical Installation, Spacing ≥ 30mm, No Forced Air Cooling Required

Connection Simple: M4 Terminals, 2.5mm² Cable Sufficient for Current Carriage

4. Compatibility

SEW Original: Directly Match MOVITRAC, MC07B, MOVIDRIVE B Micro Series Voltage compatibility: 300V/600V DC bus is universal

Multiple parallel connections: Can be connected in parallel for expansion to meet higher braking requirements

V. Typical Applications

Applicable power: 0.25–0.37kW inverter / servo drive

System configuration: Ultra-miniature driver + BW068-004 + micro servo / variable frequency motor

Typical working conditions:

Precision instruments, medical equipment, small rotating tables

Micro-sized conveying lines, light-load lifting tables, electronic manufacturing equipment

3C automation, micro-inertia positioning systems, robot end effectors

Small packaging machinery, laboratory equipment, micro-pump valve control

VI. Selection and Installation Tips

Power matching: Braking power ≤ 0.4kW (continuous)

Resistance matching: The recommended braking unit for the micro driver is 68Ω

Voltage matching: DC bus ≤ 600V DC

Heat dissipation: Vertical installation, spacing ≥ 30mm, natural cooling is sufficient

Cabling: Short, thick, straight wiring (≥ 2.5mm² cable), reduces interference

Protection: Temperature control switch connected to the driver's BRK terminal to achieve overheat protection

VII. Order Information

Model: BW068-004 (aluminum case, IP20)

Variant: BW068-004-T (net cover, IP54)

Order number: 8220810

Guarantee: 12 months

Standard equipment: Resistance body, installation screws, temperature control switch wire

VIII. Comparison of Micro Resistors in the Same Series

BW047-004: 0.4kW / 47Ω (suitable for 0.37–0.75kW)

BW068-004: 0.4kW / 68Ω (current) (suitable for 0.25–0.37kW)

BW027-006: 0.6kW / 27Ω (suitable for 0.75–1.5kW)

BW033-012: 1.2kW / 33Ω (suitable for 2.2–5.5kW)