Description

The ABB PSR9 is the smallest model in the PSR electronic soft starter series, rated at 9 A for three-phase induction motors up to 4 kW at 400 V. Designed for the smallest practical soft start application, the PSR9 provides controlled voltage ramp starting for small motors in applications where direct-on-line starting would cause objectionable mechanical shock, inrush current disturbance, or supply network voltage dips. It covers the important small motor range used in small pump starters, fan drives, conveyor feeders, and auxiliary machinery in industrial and commercial plant.

The PSR9 complies with IEC 60947-4-2 and mounts on standard 35 mm DIN rail, fitting within compact motor control panel designs. The two-parameter front-panel adjustment (initial voltage and ramp time) enables simple commissioning of the start profile for the specific load. A bypass contactor is recommended for continuous operation to avoid thyristor losses during the running period. Despite its small size, the PSR9 provides the same quality of voltage ramp control as the larger PSR models, using the same thyristor switching technology scaled for the 9 A current rating.

The PSR9 is used in small pump controls, auxiliary fan starters, small conveyor drives, and other 4 kW and below motor applications in industrial, commercial, and building services installations. It is compatible with ABB’s motor control accessory range and is supported by co-ordination data for designing complete protected motor starter assemblies. Panel builders and electrical engineers will find the PSR9 a practical and cost-effective entry into soft start motor control for the smallest motor sizes where reduced starting current or smooth mechanical starting is a requirement of the application.