Product Details:

The SEW BW068-004 braking resistor is an original external dynamic braking resistor designed for SEW MOVIMOT integrated inverter gearmotors, and it can also be matched with MOVIDRIVE MDX61B, MD60A and MOVITRAC B series drives for decentralized automation systems. Its nominal resistance value is 68 ohms and the continuous braking power is 0.4kW under 100% cyclic duration factor. This compact low-power resistor is engineered for light-duty four-quadrant working conditions, which can absorb instantaneous regenerative energy produced by the motor during intermittent deceleration and stop cycles. This base model BW068-004 does not come with a built-in thermal contact switch. According to machinery functional safety requirements, users need to install an external thermal protection relay in the wiring circuit to realize independent over-temperature interlock, preventing thermal accumulation and permanent burnout of the resistance core under continuous braking operation. Its core function is to convert regenerative electricity generated by the motor during rapid deceleration, emergency stop and reverse movement into heat energy, suppressing the sharp rise of the DC bus voltage of the drive and avoiding overvoltage protection faults for simple intermittent braking applications.

The internal part adopts high-precision alloy resistance wire winding structure and high-temperature inorganic insulation filler material. It can keep resistance stable within the ±10% tolerance range under repeated thermal shock and instantaneous current impact, and maintains reliable electrical performance after long-term intermittent braking cycles. The compact metal housing adopts natural convection heat dissipation design and supports cabinet installation or local mounting beside MOVIMOT gearmotors. It is connected to the braking chopper terminals of the matched SEW drive unit. The drive’s built-in monitoring logic can detect open circuit and short circuit faults of the braking loop. If the resistance winding burns open, suffers short-circuit damage, or the connecting cable is aged and disconnected, the drive will lose the regenerative energy dissipation channel. The DC bus voltage will surge sharply during deceleration, the equipment cannot complete fast stop actions normally, and the control system will trigger overvoltage fault alarm and safety interlock stop.

This braking resistor adopts IP66 protection grade, which is better than ordinary IP20 BW resistors, so it can adapt to harsher workshop environments with dust and splash risks. It is equipped with sealed wiring terminals for stable wiring connection. The working ambient temperature range is 0℃ to 55℃, and the storage temperature range is -20℃ to 70℃. The surface temperature of the resistor housing will rise significantly during braking operation. Enough heat dissipation clearance must be reserved around the installation position, and cables, wire ducts and other components cannot cover the heat dissipation surface to avoid heat accumulation and accelerated aging of the resistance core. When matching this resistor with the SEW drive, it is necessary to strictly follow the minimum braking resistance limit of the internal braking chopper to prevent burning the IGBT braking unit caused by excessively low resistance value.

This SEW BW068-004 braking resistor is widely used as maintenance replacement spare parts for light-duty logistics conveyors, small packaging auxiliary machines, labeling equipment, printing auxiliary mechanisms and other decentralized automation equipment using MOVIMOT integrated drive solutions. Most spare parts circulating on the global industrial spare parts market are fully tested refurbished stock. Before installation, technicians need to check whether the sealed shell is deformed, burnt or cracked, and use a multimeter to measure the resistance value to confirm that it is within the standard tolerance range. After wiring, complete jog test and high-speed deceleration test to verify DC bus voltage stability during braking. Regular inspection of terminal tightness and cleaning of dust on the housing surface can effectively reduce the probability of intermittent faults and extend the service life of the braking resistor and matched drive system.