Description
The ABB NBRA-656C (Order Code: 59006444) is an external, wall- or cabinet-mountable braking chopper module designed for ABB ACS600, ACS800, ACS850, ACS550, and ACS510 series AC drives. Utilizing IGBT-based pulse-width modulation, it monitors the DC link voltage and, when regeneration exceeds the drive’s capacity, switches an external braking resistor into circuit to dissipate motor deceleration energy—preventing DC bus overvoltage faults and enabling controlled, rapid stopping of high-inertia loads.
Application Scenarios
A container port crane equipped with an ABB ACS800-04 multidrive experienced frequent “DC OVERVOLT” trips during hoist-down and trolley deceleration, forcing operators to lengthen ramp times and sacrifice productivity. The retrofit solution was to install a ABB NBRA-656C braking chopper wired directly to the common DC bus, paired with a correctly sized SAFUR-type braking resistor (min. 4 Ω @400 V). The chopper’s threshold was set to activate at 780 V DC, and its ≤2 ms response time ensured regenerated energy was shunted to the resistor before the bus could rise above the drive’s trip point. Post-installation, the crane ran at full rated deceleration speed with zero overvoltage trips, and mechanical brake wear was noticeably reduced thanks to smoother electronic braking. For maintenance planners, keeping a verified ABB NBRA-656C on the critical spare list avoids costly downtime on cranes, winders, centrifuges, and other high-inertia applications.
Parameter
Main Parameters Value/DescriptionProduct Model NBRA-656C (Order No.: 59006444 / 3ABD58930784)Manufacturer ABB (ABB Drives / Sweden or Finland origin)Product Category External Braking Chopper Module (Dynamic Brake Unit)Compatible Drives ABB ACS600, ACS800, ACS850, ACS550, ACS510 (any VFD w/ DC+/- terminals)Input Voltage (AC Mains Ref.) 230 V / 400 V / 500 V AC (auto-adapts to DC bus 320–800 V DC)Peak Braking Power (60s/10min) 79.5 kW @400V | 88.4 kW @500V | 45.7 kW @230VContinuous Braking Power 9 kW @400V | 6 kW @500VMin. External Braking Resistor 4 Ω @400V | 6 Ω @500V | 2.7 Ω @230VSwitching Technology IGBT Chopper, typ. 2–4 kHz chopping frequency (factory preset)Response Time ≤ 2 ms (bus voltage threshold detection to conduction)Control Interface Enable input (24 V DC opto-isolated); Fault relay output (NO/NC, 250 V AC / 2 A)Protection Features Over-temperature (internal NTC), over-current, short-circuit, DC bus overvoltageCooling Method Forced air cooling (integral fan, thermostatically controlled)Enclosure / Mounting IP20, wall-mount or panel-mount inside drive cabinet (clearance: ≥26 mm top, ≥51 mm sides)Dimensions (H×W×D) Approx. 177.5 × 145 × 157 mmWeight Approx. 2.9 kgApprovals CE, cULus, EMC per EN 61800-3
Technical Principles and Innovative Values
- Innovation Point 1 – IGBT Chopper with Adjustable Threshold: The ABB NBRA-656C uses an industrial-grade IGBT switched at ultrasonic frequency to precisely regulate when the external resistor is engaged, based on a user-selectable DC bus activation threshold (e.g., 760 V / 780 V / 820 V DC for 400 V class). This prevents unnecessary resistor heating and maximizes energy recovery margin.
- Innovation Point 2 – Broad Voltage Auto-Sensing: Unlike fixed-threshold choppers, the NBRA-656C auto-detects the supply class (230 / 400 / 500 V AC equivalent DC bus) and adjusts its internal reference accordingly—one SKU covers most low- and medium-voltage drive installations without jumper changes.
- Innovation Point 3 – Integrated Thermal & Electrical Safeguards: Built-in NTC thermistor monitoring, desaturation-protected IGBT gate drive, and a dry-contact fault relay allow the ABB NBRA-656C to signal upstream PLCs or drives before catastrophic failure, supporting safer machine shutdown sequences.
- Innovation Point 4 – Parallel Expansion Capability: Multiple ABB NBRA-656C units can be synchronized (via fiber sync link on certain NBRA-6xx siblings; for NBRA-656C verify with ABB app note) to increase total braking capacity for very large inertia or multi-motor common-bus systems.
