Product Overview

The ABB 5366268-B​ is an internal control and thyristor-trigger PCB (Printed Circuit Board) designed for use inside ABB’s PSS (Parameter Setting Soft starter) range of compact three-phase soft starters—covering frame sizes from approximately PSS18 up to PSS570 depending on production revision. The ABB 5366268-B​ forms the “brain” of the soft starter: it houses the microcontroller that executes the soft-start / soft-stop ramp algorithm, monitors motor current via internal CTs (Current Transformers), evaluates supply voltage for under/over-voltage and phase-loss detection, drives the gate pulses to the three pairs of inverse-parallel SCRs (silicon-controlled rectifiers) via opto-isolated drivers, and indicates operational status (Ready, Running, Fault) on the front-panel LEDs of the PSS unit.When a PSS soft starter fails to initiate the start ramp, shows a persistent Fault LED with no external cause, or exhibits erratic SCR firing, the suspect component is frequently the ABB 5366268-B​ control board—either due to aged electrolytic capacitors, damaged gate-drive optocouplers from SCR short-circuit events, or corrupted EEPROM settings. Replacing the ABB 5366268-B​ (together with any obviously damaged power-stage components) typically restores full functionality without needing to replace the entire soft starter assembly, which can represent significant cost savings in MRO budgets. The board is powered from the soft starter’s internal auxiliary supply derived from the mains (or a separate 24 V DC control supply on some PSS variants) and is calibrated at the factory for the specific SCR gate characteristics and CT ratio of the PSS frame size it is intended to serve. Correct matching of the ABB 5366268-B​ revision to the soft starter’s power rating and series code is essential—later PSS units may use a revised board number (e.g., -C or -D suffix), but the -B revision remains the most commonly requested spare for units installed from the late 1990s through the 2000s.

Technical Specifications

Product Model | 5366268-BManufacturer | ABB (ABB Low Voltage Products — Drives & Soft Starters)Product Type | Soft Starter Internal Control / Thyristor Trigger Board (PCB Assembly)Primary Application | Control & firing electronics for ABB PSS Series Compact Soft Starters (PSS18…PSS570 typical range)Compatible Soft Starter Models | PSS18, PSS25, PSS30, PSS37, PSS44, PSS45, PSS57, PSS72, PSS85, PSS105, PSS142, PSS250, PSS370, PSS570 (verify by serial / rating plate)Microcontroller Function | Soft-start / soft-stop ramp generation, current-limit control, kick-start (torque boost), bypass contactor control logicProtection Features Managed | Overload (via motor FLA setting), phase loss, undervoltage, overvoltage, SCR short detection (in conjunction with power board)Gate Drive Outputs | 6 isolated SCR gate-drive signals (to 3 inverse-parallel thyristor pairs)Current Sensing Inputs | Via internal CTs on main power board (ratio-matched to PSS frame size)Status Outputs (to front panel) | RUN, READY, FAULT LEDs; optional relay outputs via power boardBoard Supply Voltage | Derived from internal aux. supply of PSS (typically 20–30 V DC regulated from mains or external 24 V DC on dual-supply versions)Operating Temp. (Board) | -10 °C to +60 °C (ambient inside starter enclosure)Storage Temp. | -40 °C to +85 °CMounting | Standoff / pillar mount inside PSS soft starter housing; connects to power board via multi-pin header / ribbonDimensions (Approx.) | 120 × 90 mm (varies slightly by revision)Weight | ≈ 80–120 gConformal Coating | Present on later revisions for humidity resistanceObsolescence Note | PSS series succeeded by PST(B)/PSTX; 5366268-B supplied as NOS / refurbished spare for legacy units