A Historical Outlook of Allis Chalmers Circuit Breakers and Siemens Allis Circuit Breakers
The Siemens Allis circuit breaker line began as the Allis Chalmers circuit breaker line. Allis Chalmers air breakers were one of the original OEM breakers made right after World War II, in 1945. Like other circuit breaker manufacturers, these early air breakers were large and mounted on slate boards, which was considered the best non-conductive material.
These early Allis Chalmers circuit breakers were G-25 and G-25a, in 600 amp frame size, G-50 and G-50A in 1600 amp frame size, G-75 and G-75 A in 3000 amp frame size, G-100 and G-100A.
Around 1955, plastics became the best non-conductive material and Allis Chalmers circuit breakers became smaller, smarter, and lighter. The over-current tripping mechanism also improved. Allis Chalmers circuit breaker division was eventually purchased by Siemens Allis.
These circuit breakers, which were made for the next twenty years, were as follows: 600 amp frame size, LA-25, LA-25A, LA-600, and, LA-600A. 1600 amp frame Allis Chalmers / Siemens Allis air circuit breakers were LA-50, LA-50A, LA-600, LA-1600A, 3000 amp frame size, LA-75, LA-75A, LA-3000, LA-3000A, and 4000 amp frame size, LA-100, LA-100A, LA-4000, and LA-4000A.
The 1980’s brought in a generation of Siemens Allis circuit breakers, that is still made today – the RL circuit breakers: RL-800 / 800 amp frame, RL-1600 / 1600 amp frame, RL-3200 / 3200 amp frame, and RL-4000 / 4000 amp frame. Siemens Allis remains a consistent and popular choice for circuit breakers and switchgear.