Chain Motors

This SOP defines the standards and procedures for the preparation, installation, operation, and maintenance of electric chain motors used in Maryland Productions (MP) and Event Revolution (RV) rigging systems. Chain motors are critical lifting devices and must be handled only by trained and authorized personnel.

Improper motor use can result in severe injury, equipment damage, or structural failure.

Purpose

  • Ensure safe and consistent use of chain motors.

  • Prevent overloads, mis-rigging, and mechanical failures.

  • Standardize inspection, deployment, and strike procedures.

  • Define clear roles and responsibilities for motor operations.

  • Support compliance with safety and industry best practices.

Who This SOP Is For

  • Rigging technicians

  • Lead riggers

  • Technical Directors

  • Project Managers overseeing motorized rigging

  • Warehouse staff prepping motors

  • Freelancers authorized to operate motors

Only trained and authorized personnel may operate chain motors.

Scope

This SOP applies to:

  • Electric chain motors (D8, D8+, C1 where applicable)

  • Motor controllers and pendant controls

  • Motor power and control cabling

  • Motor bags and storage systems

This SOP does not replace venue-specific rules or engineered rigging requirements.

Motor Safety Classifications

  • D8 Designed for static loads. Secondary safety required for overhead loads.

  • D8+ Enhanced safety features. Secondary safety typically required depending on application.

  • C1 Designed for overhead lifting above people without secondary safety when used per spec.

Motor class must be appropriate for the application.

Training & Authorization

  • Only trained personnel may install or operate motors.

  • Motor class-specific training is required.

  • Freelancers must demonstrate experience with the motor type in use.

  • PMs must confirm crew qualifications.

Unqualified operation is prohibited.

Warehouse Prep

  • Inspect motors before deployment: - Chain condition - Hook integrity - Safety latch function - Body and casing

  • Verify: - Correct chain length - Proper labeling - Certification status

  • Test motor operation briefly.

  • Pack motors with: - Correct control cables - Power cables - Bags or cases

Motors with defects must be removed from service.

Planning & Load Calculations

  • Confirm load weights including: - Truss - Fixtures - Cable - Safety factors

  • Verify motor WLL is sufficient.

  • Balance loads evenly across motors.

  • Confirm structure capacity.

Never guess weights.

On-Site Installation

Rigging the Motor

  • Verify attachment point rating.

  • Use approved hardware only.

  • Attach motor securely.

  • Ensure chain is not twisted.

  • Verify hook orientation.

Motor must be correctly seated before load.

Connecting Power & Control

  • Verify correct voltage and phase.

  • Connect control and power cables securely.

  • Keep control cables protected.

  • Ensure controller configuration matches motor setup.

Never energize before verification.

Lifting Operations

  • Establish clear communication.

  • Designate a single motor operator when possible.

  • Lift slowly and evenly.

  • Watch for: - Uneven lifting - Snags or obstructions - Abnormal noises

  • Stop immediately if an issue occurs.

Do not rush lifts.

Overhead Loads & Safeties

  • Follow motor class requirements.

  • Install secondary safeties where required.

  • Verify safeties are independent of motors.

  • Inspect safeties before load is overhead.

Redundancy is mandatory when required.

Operation During Show

  • Monitor motors and loads.

  • Restrict access to control devices.

  • Do not operate motors unless required.

  • Never adjust rigging while energized without approval.

Motor operation during show requires heightened awareness.

Strike & De-Rigging

  • Lower loads fully before disconnecting.

  • De-energize power.

  • Disconnect control and power cables.

  • Inspect motors during removal.

  • Pack motors carefully.

Strike must be controlled and deliberate.

Maintenance & Inspection

  • Perform regular inspections per manufacturer guidelines.

  • Track service intervals and certifications.

  • Remove motors from service if: - Chain wear exceeds limits - Hooks are damaged - Motors malfunction

Only qualified technicians may service motors.

Responsibilities

Rigging Technicians

  • Install and operate motors safely.

  • Follow approved procedures.

  • Report issues immediately.

Lead Riggers

  • Verify load calculations.

  • Oversee motor operations.

  • Enforce safety standards.

Project Managers

  • Define motor scope.

  • Verify crew qualifications.

  • Coordinate venue requirements.

Warehouse Staff

  • Inspect and prep motors.

  • Maintain service records.

  • Remove unsafe motors from service.

Quality Control

  • No uninspected motors in use.

  • Load calculations verified.

  • Safeties installed when required.

  • Issues corrected immediately.

Motor safety is non-negotiable.