Product Details:

The SEW BW027-006 braking resistor is an original grid-style dynamic braking resistor designed to pair with SEW MOVIDRIVE MDX61B, MD60A and MOVITRAC B series variable frequency inverters and servo drives. Its nominal resistance is 27 ohms, and the continuous power rating reaches 6kW under 100% duty cycle. It features outstanding overload performance for cyclic braking scenarios, which can withstand much higher instantaneous peak power for short periods when the motor feeds back regenerative energy. This base version does not come with an integrated thermal contact switch. For machine safety compliance, users must add an external thermal relay in the wiring loop to provide independent over-temperature protection and interlock signal to the drive or PLC. The core function of this resistor is to convert the regenerative electricity generated by the motor during rapid deceleration, emergency shutdown, downward movement of loads and reverse operation into heat energy, so as to suppress the sudden rise of the DC bus voltage inside the drive and eliminate frequent overvoltage protection faults that commonly occur on four-quadrant equipment.

Inside the resistor housing, high-grade alloy resistance wire is wound and filled with high-temperature inorganic insulating material. It can keep its resistance value stable within the ±10% tolerance range under repeated thermal shock and short-time high-current impact, and maintains reliable electrical performance after long cycles of intermittent braking. The metal grid casing adopts natural convection cooling and cabinet mounting design, with sturdy threaded power terminals for secure wiring to the braking chopper terminals of the corresponding SEW drive. The drive’s built-in monitoring logic can detect open-circuit and short-circuit faults on the braking circuit. If the resistance winding burns open, suffers short-circuit damage, or the connecting cable is broken, the drive will lose the path to dissipate regenerative energy. The DC bus voltage will spike sharply during deceleration, the equipment will fail to achieve fast stop and load lowering functions, and the control system will trigger fault alarms and safety interlock shutdown.

This braking resistor has an IP20 protection rating. The working ambient temperature range is 0℃ to 55℃, and the storage temperature range is -20℃ to 70℃. The surface of the grid housing will get extremely hot during continuous braking operation. Enough heat dissipation gap must be reserved around the resistor during installation. Cables, cable ducts and other electrical components cannot cover the heat dissipation grid, otherwise heat will be trapped and accelerate the aging of the resistor core. When matching this resistor to a SEW drive, it is necessary to check the minimum allowed braking resistance of the internal braking chopper, to avoid burning the IGBT braking unit caused by an excessively low resistance value.

This SEW BW027-006 braking resistor is widely used as maintenance replacement spare parts for medium and heavy material conveyors, packaging production lines, printing and converting equipment, medium-sized hoisting machinery and other automation systems that require stable and frequent braking. Most spare parts available on the global industrial spare parts market are fully tested refurbished stock. Before installation, technicians need to inspect the grid shell for deformation, burn marks and cracks, and use a multimeter to measure the resistance value to confirm it falls within the standard tolerance range. After wiring is completed, perform high-speed deceleration and load lowering running tests to verify stable DC bus voltage during braking. Regularly clean dust and debris accumulated on the heat dissipation grid and check terminal contact tightness, which can effectively reduce the chance of overheating damage and extend the service life of the braking resistor and the matched drive system.