External Limit Switch (SK-1309).pdf

This document is a technical specification drawing for a limit switch assembly used in a cooling tower rolling door system. The drawing illustrates the mechanical design and installation requirements for magnetic proximity limit switches that control the motor drive and brake functionality of rolling doors on both the west and east sides of a cooling tower.

The specification details the precise positioning and adjustment requirements for two magnetic proximity unit switches (Gemini 2302 series). The magnetic switch must be positioned on the third door slat with a safety margin of at least 2.5 inches from the top of the door channel to prevent the door from leaving the channel if the motor drive fails. The up limit switch should be adjusted approximately 4 inches above the magnetic switch activation point to stop motor drive operation, while the wet door down limit switch must be positioned 2 to 3 inches from the bottom of the door channel to prevent freezing or door binding during winter operation. The drawing includes a limit switch mounting detail type diagram showing the physical installation configuration, sensing edge contact points, magnet placement on the lower metal door lip, and wire lead routing to the unit switch box. This technical specification establishes the functional and spatial requirements necessary for safe and reliable operation of the cooling tower door control system.