Guardmaster 440T

The Allen-Bradley Guardmaster 440T is a trapped key interlock family designed to enforce safe sequencing of machine access, energy isolation, and guard control across a wide range of industrial machinery. With over 1,200 catalog numbers, the 440T series spans rotary enclosure interlocks, solenoid release units, bolt units, timed-delay units, and multi-key exchange modules, making it one of the most comprehensive trapped key platforms available. Catalog numbers follow the pattern 440T-<family><contacts><rating><options>: the family code identifies the mechanism type (e.g., MSRUE = solenoid release, MRKSE = rotary enclosed, MSBLE = bolt, MSTUE = timed-delay, MKEXE = key exchange), while subsequent digits encode contact configuration and current rating. Popular in-stock units include the 440T-MSRUE10AA (solenoid release, 4 N.O., 20 A, 24V DC) and the 440T-MS3417D0K0K0K (triple solenoid release, 4 N.O., 20 A). For full catalog-number breakdowns and specifications, consult the Guardmaster 440T Technical Data Sheet.