Mill-type limit switches

Control limit track type switches operate at 600 V maximum, AC or DC. Types of operators for these switches are roller lever (460 FPM), standard fork lever (700 FPM), heavy-duty fork lever (340 FPM) and counter, and counterweight with reset for over-hoist applications. Standard spring-return switches operate in one direction only (contacts change state when lever is moved in one direction from centre).

Crane power circuit limit switches are mounted on a crane trolley to prevent over-travel of the crane hook when hoisting. These enclosed switches are available as single and duplex types from 50–500 hp. Power circuit limit switches use double-pole, double-throw power circuit contacts to disconnect the main power to the hoist motor. On DC applications, a resistor is required with the limit switch to provide dynamic braking.