Product Details:

The SEW BW047-004 braking resistor is an original wire-wound dynamic braking resistor developed for SEW MOVIDRIVE MDX61B, MD60A and MOVITRAC B series variable frequency drives and servo drives. It has a nominal resistance value of 47 ohms and a continuous braking power of 0.4kW under 100% cyclic duration factor. It is a low-power compact resistor solution for light-duty four-quadrant working conditions, and it can withstand short-time peak regenerative energy impact during intermittent deceleration and stop actions. This base model BW047-004 does not integrate a built-in thermal contact switch. In accordance with machinery safety standards, users need to configure an external thermal protection relay in the wiring circuit to realize independent over-temperature interlock protection, avoiding thermal accumulation and permanent burnout of the resistance core under continuous braking cycles. 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, so as to suppress the sharp rise of the DC bus voltage inside the drive and eliminate overvoltage protection faults that often occur in simple four-quadrant applications.

The internal structure adopts high-precision alloy resistance wire winding and high-temperature inorganic insulation filling material. It can keep stable resistance value within the ±10% tolerance range under repeated thermal shock and instantaneous current impact, and maintains reliable electrical performance after long cycles of intermittent braking. The compact cylindrical wire resistor structure is designed for convenient installation inside electrical cabinets, and it is equipped with clearly marked threaded power terminals for direct wiring connection with the braking chopper terminals of the matched SEW 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 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. The working ambient temperature range is 0℃ to 55℃, 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 matching this resistor 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 the excessively low resistance value.

This SEW BW047-004 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 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.