Rigging Chain Motors

This SOP defines the standards and procedures for preparing, inspecting, deploying, operating, and resetting electric chain motors (hoists) used by Maryland Productions (MP) and Event Revolution (RV). Chain motors are life-safety–critical devices and must be handled only by trained and authorized personnel following strict inspection, rating, and communication standards.

Improper motor use can result in serious injury, death, or catastrophic equipment failure.

Purpose

  • Ensure safe and correct use of chain motors.

  • Standardize inspection, deployment, and operation procedures.

  • Prevent overloads, mis-rigging, and uncontrolled movement.

  • Protect personnel, performers, venues, and equipment.

  • Establish clear authority and responsibility for motor operations.

Who This SOP Is For

  • Qualified rigging technicians

  • Lead riggers and Technical Directors

  • Warehouse staff prepping motors

  • Project Managers overseeing rigging scope

  • Authorized freelancers approved for motor operation

Only personnel approved by MP/RV may install, connect, or operate chain motors.

Scope

This SOP applies to:

  • Electric chain motors (single- and dual-speed)

  • Motor controllers and control cables

  • Motor power cabling and connectors

  • Motor chains, hooks, and safety latches

  • Temporary overhead lifting for production use

Permanent building hoists and scenic automation systems are excluded.

Chain Motor Safety Rules

  • Treat all overhead loads as potentially hazardous.

  • Never exceed the motor’s rated Working Load Limit (WLL).

  • Never shock-load a motor.

  • Never work under an unsecured or moving load.

  • Maintain clear communication at all times.

  • Stop immediately if anything behaves unexpectedly.

No show requirement overrides rigging safety.

Motor Identification & Ratings

Each chain motor must have:

  • Clearly marked: - Manufacturer - Capacity (WLL) - Serial number

  • Functional: - Upper and lower limit switches - Safety latch on hook

If a motor’s rating or condition is unclear, it must not be used.

Warehouse Prep & Inspection

Before deployment:

  • Inspect motor body for: - Cracks or deformation - Oil leaks

  • Inspect chain for: - Twists - Kinks - Excessive wear or rust

  • Verify: - Proper operation of limit switches - Control pendant functionality - Correct power connector type

  • Confirm: - Correct motor quantity and capacities

  • Remove any questionable motor from service immediately.

Motors must be inspected before every use.

Motor Rigging & Installation

Mounting

  • Use only rated hardware compatible with motor capacity.

  • Verify beam, truss, or structure rating.

  • Ensure hooks are fully seated with safety latches engaged.

  • Avoid side-loading hooks.

Improper mounting compromises load paths.

Load Attachment

  • Attach loads using approved rigging methods.

  • Verify balanced loading.

  • Avoid point-loading truss chords unless designed for it.

  • Use secondary safeties where required.

Balanced loads extend motor life and improve control.

Power & Control

  • Verify correct voltage and phase.

  • Confirm motor controller compatibility.

  • Route control and power cables cleanly.

  • Protect cables from pinch points and traffic.

  • Label motor control channels clearly.

Power and control errors cause unpredictable behavior.

Operational Procedures

Before Lifting

  • Clear area beneath load.

  • Confirm communication protocol: - Single designated motor caller

  • Verify: - Load is secure - Travel path is clear

Lifting without coordination is prohibited.

During Movement

  • Move loads smoothly and deliberately.

  • Avoid sudden starts or stops.

  • Watch for: - Chain binding - Uneven movement - Unexpected noise

  • Stop immediately if irregularities occur.

Smooth operation protects motors and structures.

After Positioning

  • Verify final trim heights.

  • Set limits where applicable.

  • Confirm load stability.

  • Apply secondary safeties if required.

Never leave questionable loads unattended.

Environmental Considerations

  • Monitor: - Wind (outdoor shows) - Temperature extremes - Rain or moisture

  • Adjust operations or stop work as conditions require.

Environmental changes affect load safety.

Strike & Reset

  • Lower loads in a controlled manner.

  • De-energize motors before handling.

  • Inspect motors and chains during strike.

  • Note any issues or abnormal behavior.

  • Coil chains properly.

  • Scan motors back into inventory.

Strike inspection protects the next show.

Handling & Storage

  • Transport motors in approved cases.

  • Protect chains from tangling or kinking.

  • Store motors clean, dry, and supported.

  • Keep control cables organized and labeled.

Proper storage extends motor service life.

Roles & Responsibilities

Rigging Technicians

  • Install and operate motors safely.

  • Follow approved rigging plans.

  • Report issues immediately.

Lead Riggers / Technical Directors

  • Approve motor usage and configurations.

  • Oversee safety and communication.

  • Enforce stop-work authority.

Warehouse Staff

  • Inspect, prep, and reset motors.

  • Remove unsafe motors from service.

Project Managers

  • Ensure qualified rigging staff are assigned.

  • Support safety-driven decisions.

Quality Control

  • Motors inspected before every use.

  • Loads within rated limits.

  • Communication protocols followed.

  • Issues documented and addressed.

Chain motor safety is non-negotiable.