Allen-Bradley 505-B0D-23 NEMA Size 1 Reversing Starter Unit

Module Feature

505-B0D-23 belongs to Bulletin 505 NEMA full voltage reversing starter manufactured by Allen-Bradley (Rockwell Automation). NEMA Size1 open type assembly,control coil rated 115-120V,60Hz. Suffix "-23" means the unit is supplied without overload relay,external overload protection needs to be added on site. Equipped with forward and reverse contactors plus mechanical interlock mechanism to prevent both contactors closing simultaneously and avoid phase short circuit. Auxiliary contacts are integrated for PLC status feedback and control interlock. Widely used for bi-directional operation of conveyors,machine tools,hoists and material handling equipment.

Working principle

When forward coil energizes,the forward main contactor closes and motor rotates forward. To reverse motor direction,stop command must be triggered first; then reverse coil energizes and swaps two motor phases to realize reverse rotation. The mechanical interlock physically locks the opposite contactor to prevent dangerous short-circuit condition. Auxiliary contacts feed running/fault status to external control system.

Onboard components

Forward main contactor,reverse main contactor,mechanical interlock assembly,auxiliary contact set,115-120V 60Hz coil assembly,main power terminal block,control terminal block,metal mounting base plate.

LED indicators

No built-in LED indicators; status feedback comes from auxiliary contact signal to external control cabinet.

Hardware self-diagnosis

Contact wear inspection,coil continuity resistance 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-B0D-23 Brand:Allen-Bradley Device type:Bulletin505 NEMA Size1 Full Voltage Reversing Starter NEMA frame:Size1 Control coil:115~120V,60Hz Operation:Forward / Reverse full voltage starting Interlock:Mechanical interlock Overload relay:Not included (suffix -23) Cooling:Natural convection cooling Protection:Short circuit protection via external fuse or 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 Bulletin505 NEMA Size1 open reversing starter with 115-120V coil,without overload relay

Installation

Follow strict ESD safety procedure before handling.Mount base plate firmly inside control cabinet.Connect three-phase main power and motor cables to main power terminals.Wire control circuit to forward/reverse coil and auxiliary contacts.Verify mechanical interlock action before power commissioning.

Interface

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

Diagnostic

Coil cannot pull in:coil burnout or missing 115-120V control voltage. Reverse function failure:stuck mechanical interlock or auxiliary contact interlock fault. Contact arcing:motor overload or cable short circuit. Dangerous simultaneous closing:broken mechanical interlock assembly.

Product Brief

Allen-Bradley 505-B0D-23 Bulletin505 NEMA Size1 open type full voltage reversing motor starter,115-120V 60Hz control coil,mechanical interlock design,supplied without overload relay for bi-directional conveyor and machine motor forward/reverse control.