Baldor RTA4-20 Enclosed Braking Transistor Assembly

Baldor RTA4-20 Enclosed Braking Transistor Assembly is a dynamic braking module designed to dissipate motor energy during stop commands in Baldor drive systems. The module includes a braking transistor and a gate-driver circuit board, fully assembled and mounted inside a NEMA 1 enclosure for indoor installation, and is intended for use with External Dynamic Braking Resistor Assemblies (RGA) to convert the motor’s kinetic energy into heat through a braking resistor. The RTA4-20 corresponds to the 380–480 VAC family within Baldor’s RTA dynamic braking assemblies, one of several voltage variants that also include 208–230 VAC and 550–600 VAC configurations, enabling compatibility with a broad range of Baldor drives. This model provides a compact, integrated braking solution that lets industrial 3‑phase motors decelerate with a controlled braking profile when commanded by the drive, helping protect mechanical systems and extend drive life. When paired with the matching RGA braking resistor, the assembly forms a complete braking path installed as part of the drive’s dynamic braking circuit, with the enclosure providing straightforward mounting in control panels.