Allen-Bradley 505-B0*-23 NEMA Size 1 Reversing Starter Unit

Module Feature

505-B0*-23 belongs to Bulletin 505 NEMA full voltage reversing starter manufactured by Allen-Bradley (Rockwell Automation). NEMA Size1 frame,open type without metal enclosure. The suffix "-23" indicates the unit is supplied without overload relay,external overload protection shall be added separately. It contains forward and reverse contactors with mechanical interlock to prevent simultaneous closing of two contactors. Coil voltage code marked by the wildcard *,available in 115/120V,230/240V etc. Widely used for bi-directional operation of conveyors,machine tools,hoists and material handling equipment.

Working principle

When forward coil energizes,the forward contactor closes and motor runs forward. When reverse coil energizes after stop command,the reverse contactor swaps two motor phases to reverse rotation. Mechanical interlock physically blocks forward and reverse contactors from pulling in at the same time to avoid phase short circuit. Auxiliary contacts provide status feedback for PLC control and interlock logic.

Onboard components

Forward main contactor,reverse main contactor,mechanical interlock assembly,auxiliary contact set,coil assembly,main power terminal block,control terminal block,metal mounting base.

LED indicators

Status indication from external control circuit or auxiliary contact feedback.

Hardware self-diagnosis

Contact wear inspection,coil continuity test,mechanical interlock function check,wiring short circuit detection.

Programming software

No dedicated programming software,controlled by external PLC or hardwired relay logic.

Electrical & Process Parameters

Model:505-B0*-23 Brand:Allen-Bradley Device type:Bulletin505 NEMA Size1 Full Voltage Reversing Starter NEMA frame:Size1 Operation:Forward / Reverse full voltage starting Interlock:Mechanical interlock Overload:Not included (suffix -23,no overload relay) Coil voltage:Configurable (wildcard *) Cooling:Natural convection cooling Protection:Short circuit protection via external fuse/circuit breaker

Mechanical & Structure

Mounting:Back plate mounting inside control cabinet Protection class:Open type (IP00 bare assembly) Housing:No enclosure,metal base plate

Environmental

Operating temperature:-10℃ ~ +40℃ Storage temperature:-40℃ ~ +85℃ Ambient humidity:5~95% non-condensing Certification:CE,UL compliant Status: Allen-Bradley NEMA Size1 open reversing starter without overload relay for bi-directional motor control

Installation

Follow ESD safety procedure before handling.Mount the base plate securely inside cabinet.Connect three-phase main power and motor wiring to power terminals.Wire control circuit to forward/reverse coil and auxiliary contacts.Verify mechanical interlock function before power on.

Interface

Main power input terminal,motor output terminal,coil control terminal,auxiliary contact terminal.

Diagnostic

Coil no pull-in:coil burnout or control circuit missing voltage. Cannot reverse:mechanical interlock stuck or auxiliary contact interlock fault. Contact arcing:overload or motor short circuit. Simultaneous contact close:broken mechanical interlock.

Product Brief

Allen-Bradley 505-B0*-23 Bulletin505 NEMA Size1 open type full voltage reversing motor starter,mechanical interlock design,suffix -23 without built-in overload relay,for bi-directional conveyor and machine motor forward/reverse control.