Product Description:

The 175U3428 brake resistor is engineered by Danfoss for the VLT Brake Resistors series. This component is installed across the DC bus of a VLT drive so that kinetic energy returned by a decelerating motor is converted into heat instead of causing an inverter overvoltage trip. By presenting a fixed resistive load, the assembly provides predictable braking torque and protects production equipment that performs rapid starts, stops, or axis reversals.

The core element of the module has a resistance of 56 Ω, and the tolerance band of ±10% keeps braking current within the drive’s design limits. Under steady thermal conditions, the housing dissipates 3200 W, while brief energy surges can be absorbed at 39.9 kW when operation is restricted to a 10% duty cycle. Air slots and drip protection satisfy the IP21 enclosure class, so the unit can be mounted inside ventilated panels without exposure to direct water spray. The insulation resistance exceeds 20 MΩ when measured at 1000 V. The dielectric system withstands a high-potential test of 2500 V AC for one minute. Drive leads may be terminated with stranded conductors up to 16 mm², and the separate temperature switch cable accepts conductors as large as 4 mm² for reliable signaling.

Thermal protection is provided by a normally closed switch that opens at 180 °C and is rated for 2 A at 250 V AC. For applications with longer deceleration sequences, the resistor can repeatedly handle 9.9 kW at a 40% duty cycle, providing an intermediate capacity between its continuous and peak limits. The temperature switch can connect directly to the drive’s fault input, allowing the brake chopper to be disabled if the resistor overheats. The unit has a mass of 14.6 kg, which requires a secure mounting surface while remaining manageable during panel installation.