LiftMaster K75-50893 Safety Interlink Kit

Motor Disable Interlock for LiftMaster Gate Manual Override

The LiftMaster K75-50893, marketed as a Safety Interlink Kit, is a motor interlock assembly designed to disable the gate operator when a manual crank is inserted. Installed directly behind the crank input shaft, this assembly uses built-in limit switches to cut power to the drive motor, preventing accidental motor engagement while a user is manually operating the gate. This is a critical UL325-compliant safety device included in LiftMaster's legacy SL3000 series systems.

Key Features

• Disables motor while crank is engaged
• Integrated limit switches automatically cut drive power
• Protects users during emergency or maintenance cranking
• Installed behind the crank input; triggered by crank tool insertion
• Labeled by LiftMaster as “Safety Interlink Kit” but functions as a motor interlock

Technical Specifications

• Part Number: K75-50893
• Function: Manual override interlock (motor shutoff via limit switches)
• Compatibility: LiftMaster legacy SL3000 and related models with crank access
• Trigger Mechanism: Crank insertion through safety interlock plate
• Application Type: Commercial, Industrial, Secure Perimeter
• Installation: Mounts behind motor crank input; wired to safety circuit terminals

Conclusion

Despite its OEM label, the K75-50893 is a true crank safety interlock, critical for protecting personnel during manual gate override. It meets safety codes by preventing motor activity during crank use, and is a required component in legacy LiftMaster Elite SL3000-series installations where manual release is supported.