Product Details:

The SEW BW072-003 braking resistor is an original wire-wound dynamic braking resistor designed for SEW MOVITRAC B series 400/500V inverters, part number 8260583. It has a nominal resistance of 72 ohms with a tolerance of ±10%, and the continuous power is 230W under 100% cyclic duration factor. It supports graded peak power output under different duty cycles: 310W at 50% cdf, 420W at 25% cdf, 580W at 12% cdf and 1000W at 6% cdf. This base model BW072-003 does not integrate a built-in thermal contact switch, and the recommended trip current for the external bimetal thermal relay is 0.6A. It can be installed under the inverter heat sink with optional FKB mounting kit or mounted on standard DIN rail inside the cabinet. Its core function is to convert the regenerative electric energy generated by the motor during rapid deceleration, emergency stop and reverse operation into heat energy, suppressing the sharp rise of the DC bus voltage of the drive and preventing overvoltage protection faults in simple four-quadrant working conditions.

The internal structure adopts high-quality alloy resistance wire winding and high-temperature inorganic insulation filler. It can keep stable resistance value within the tolerance range under repeated thermal shock and instantaneous current impact, and maintain stable electrical performance for long-term intermittent braking cycles. It is connected to the braking chopper terminals of the matched SEW MOVITRAC B drive. 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 realize fast stop functions normally, and the control system will trigger overvoltage fault alarm and safety interlock stop.

This braking resistor adopts IP20 protection grade, equipped with compact threaded power terminals for convenient wiring. The working ambient temperature range is -20℃ to +45℃, and the storage temperature range is -20℃ to 70℃. The surface temperature of the resistor body will rise obviously during braking operation. Enough heat dissipation clearance must be reserved around the installation position. Cables, wire ducts and other electrical components cannot cover the heat dissipation area, otherwise heat will accumulate and accelerate the aging of the resistance core. When this resistor is installed under the inverter via FKB submount accessory, the power derating curve must be followed because the heat dissipation condition will be limited. When matching with the SEW drive, it is necessary to strictly check the minimum braking resistance limit of the internal braking chopper to prevent the IGBT braking unit from being burned out due to excessively low resistance value.

This SEW BW072-003 braking resistor is widely used as maintenance replacement spare parts for light-duty material conveyors, small packaging auxiliary machines, labeling equipment, light printing auxiliary mechanisms and other decentralized automation equipment that require low-power intermittent braking. Most spare parts circulating on the global industrial spare parts market are fully tested refurbished stock. Before installation, technicians need to check whether the resistor body 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 the jog test and high-speed deceleration test to verify the stability of DC bus voltage during braking. Regular cleaning of dust accumulated on the resistor surface and inspection of terminal tightness can effectively reduce the probability of intermittent faults and extend the service life of the braking resistor and the matched drive system.