Honeywell 51ML72 Heavy-Duty Side Rotary Limit Switch

Overview

Core Technical Specifications

1. Mechanical Structure

• Actuator type: Side rotary head (no lever arm, user-configurable roller lever optional)
• Reset mode: Spring automatic return
• Rotation direction: Clockwise / counterclockwise bidirectional trigger
• Operating torque: 5 in-lb (0.56 N·m)
• Travel parameters:
   
  Pre-travel: 20°; Differential travel: 15°; Over-travel: 50° total stroke
• Housing: Die-cast aluminum alloy, high mechanical impact resistance
• Wiring port: 1/2" NPT threaded conduit entry
• Overall dimension: 53.85 × 81.03 × 153.92 mm
• Mechanical service life: Millions of cycles for long-term continuous operation

2. Electrical Contact Parameters

• Contact form: DPDT (2NO + 2NC snap-action positive opening contacts)
• Rated load: 10A @ 250VAC / 250VDC, NEMA A300 rating
• DC low-current rating: Max 300mA @ 250VDC
• Contact material: Silver alloy, anti-oxidation, stable signal under frequent switching
• Terminal type: Internal screw terminals for cable connection

3. Environmental & Protection

• Protection grade: IP67, NEMA 1/4/12/13
• Dustproof, waterproof, oil-resistant, suitable for workshop with cutting fluid, splash water
• Operating temperature: -20℃ ~ +70℃
• Compliance: RoHS green environmental standard, CE certified

Key Features

1. Heavy-duty die-cast sealed housing, anti-collision and anti-corrosion for machine tool, metallurgy, port equipment
2. Bidirectional rotary trigger, flexible installation orientation to match different mechanical stroke structures
3. DPDT dual independent contact groups, can simultaneously output position feedback signal and safety interlock signal
4. Snap-action fast break contact, consistent switching point, avoid signal drift caused by mechanical wear
5. Standard NPT conduit wiring interface, convenient for armored cable wiring, good electromagnetic shielding effect
6. Modular actuator accessories, can be equipped with roller levers of different lengths to adjust trigger stroke

Application Scenarios

• Machine tool travel limit, gantry stroke positioning
• Conveyor, palletizing robot position detection and safety interlock
• Construction machinery, forklift, port lifting equipment stroke protection
• Packaging, textile, printing machinery position stop control
• Hydraulic equipment, large automation equipment over-travel safety protection