Rope Elevator Governor & Safety Device | TOSHIBA Machine Room Explained

Currently, two organizations are certified by ANSI to accredit elevator inspectors: the Elevator Industry Preservation Fund (through the International Union of Elevator Constructors) and NAIA (National Association of Elevator Safety Authorities International). Both must follow QI1 requirements including 10 continuing education hours annually, original examination, and possession of all necessary code books. ASME develops A17.1, one of the oldest and most respected technical standards in the United States, comparable to the National Electrical Code. ASME serves as the parent organization that develops foundational elevator standards while A77 handles specific technical standards for technicians, representing a vertical integration of elevator technology standards.

La norma ASME A17.1 establece reglas de seguridad para ascensores, incluyendo factores mínimos de relación de sobre (diámetro de polea/diámetro de cable) y factores de servicio. A diferencia de la norma europea, la norma americana permite menores relaciones de sobre y admite el uso de cables de menor diámetro en ciertos casos.

The European standards EN 81-20 and EN 81-50, published in August 2014 and effective from August 31, 2017, replaced the older EN 81-1 and EN 81-2 standards, establishing comprehensive safety requirements for new passenger and goods elevators, including rules for accessibility, safety, and component verification procedures.

Elevator safety in Thailand is governed by the Building Control Act (B.C.A.) with five versions (2522, 2535, 2541, 2550, 2558), ensuring urban order, building safety, fire prevention, and public health. Buildings are classified by area and height: residential/small (≤500 sqm, ≤15m), large (>1,000 sqm, 15-23m), extra-large (≥10,000 sqm), and high-rise (≥23m). Firefighting elevators require 630 kg minimum capacity, stop at every floor, and travel within 1 minute. Standards include Thai, American (ANSI A17.1, ASME), European (EN 81, EN 115), Singapore (SLS), and UK (CIBSE) standards. Components include elevator shaft with car and counterweight (balancing 50% of load), machine room with motor and controls, and elevator pit. Safety systems include speed governors limiting speed to 125% of design speed, safety gears locking the car to guide rails, limit switches with final limit switches as backup, and buffer systems (oil or spring) in the pit. Door interlocks prevent movement when doors are open.

ASME A17.1 is the safety code for elevators and escalators, written for commercial buildings. Key requirements include: power requirements (often three-phase power), structural requirements (escalators weigh tons and need reinforced pits and heavy-duty support), weatherproofing (outdoor installation requires specialized components, drainage, and heating elements), and safety features (sensors, emergency stops, skirt guards, comb plates). The code assumes indoor commercial environments, not suburban residential porches.

This section details safety governor testing and maintenance procedures. Safety governors require periodic testing to ensure proper operation. Testing is performed by adding oil to the safety governor's chamber, which increases the effective mass of the ring and lowers the trip threshold. This allows testing at lower frequencies (e.g., 3100 rpm instead of 3300 rpm). The complete chain is verified: sensor detection, signal transmission, solenoid operation, and stop valve closure. Testing should be done during operation, especially after long shutdowns, typically before synchronization.

Safety valves require periodic inspection combined with internal and external vessel examinations: (1) 12 months for Category A and B boilers; (2) 15 months for Category C boilers; (3) 24 months for Category A boilers with annual pressure testing. The valve must undergo accumulation test, functional test, and opening test. Online testing is not permitted for annual inspection per NR13 - valves must be disassembled, inspected, and calibrated on a proper maintenance bench.

Before conducting pull tests, the testing machine must be calibrated. Calibration requirements include: (1) Third-party calibration must be valid with a sticker showing the calibration date (e.g., 26/11/2024), (2) Daily morning calibration must be performed before use, (3) The responsible person must be identified and the SF board must be displayed.

Safety Category 2 requires the safety function to be checked at machine startup and periodically by the control system. If a fault is detected, a safe state must be initiated or a warning provided. ISO 13849 assumes 100 tests per interaction, meaning if a guard door opens once per shift, it must be tested 100 times per shift. This ensures loss of safety function is detected between checking intervals. Safety monitoring relays constantly monitor inputs and use normally closed contacts to test output safety ratings, providing diagnostic coverage when contacts weld.

Spoke pull-through testing measures how much force is required to pull a spoke out of the rim. The machine pushes the hub down until spokes begin to pull through. This test measures the rim's ability to hold spokes under stress. The deflection point indicates the rim's strength and durability.

Three main elevator types exist: Traction elevators are cable-driven with traction machines, cables, counterweights, overspeed governors, and controllers. Machine rooms are typically in penthouses above the hoistway. Hydraulic elevators use pistons powered by hydraulic fluid, with machine rooms near the hoistway (first floor or basement). MRL (Machine Roomless) elevators have components contained within the hoistway except for the Controller, which is located adjacent to the motor near the top floor. MRL elevators are cheaper, easier to maintain, and more condensed than hydraulic elevators, making them the predominant choice for new installations. Motors can be mounted on sidewalls, head beams, or in pits, requiring rescuers to adapt their approach.

MRL (Machine Room Less) elevators eliminate traditional machine rooms, liberating construction space for other uses. Key features include bidirectional parachute safety systems, silent operation without reducers, and automated emergency rescue. Technical specifications range from 450-2500 kg capacity, 1-2 m/s speed, and 60m travel distance. The suspension uses 21 cables with deflection pulleys on both counterweight and cabin chassis. The motorization employs synchronous permanent magnet motors with low consumption, compact size, and high torque. Pulley diameters range from 360-520 mm with cable diameters of 160-210 mm. The brake system uses spring-compression brakes with two independent plates and manual disconnection levers. Electrical connections include variable frequency inverters, thermal protectors, and micro switches for brake monitoring. The brake regulation is factory-set with high precision. MRL elevators use absolute encoders (Heidenheim SN 13 13) providing continuous rotational reference without zero-point detection. Cable installation requires alignment with longitudinal markings to prevent torsion damage. The UCM (Unintended Card Moment) system detects unintended cabin movement and triggers the speed governor. The emergency power system (UPS) activates during power cuts, moving the elevator to the nearest floor and opening doors for passenger evacuation. MRL elevators are delivered in modular packaging organized by installation sequence, with guide supports and hardware pre-organized for each floor level. Guide rails have specific upper section lengths (approximately 1500mm) with pre-drilled holes. Installation can start from top to bottom or bottom to top, with calculations determining exact positions.

Machine-room-less (MRL) elevators eliminate the need for a separate machine room by integrating the motor and control systems directly into the hoistway, featuring energy-efficient regenerative converters that return braking energy to the building's electrical grid, destination-based dispatch systems that optimize traffic flow by assigning passengers to specific cars based on their destinations, and advanced safety systems including multi-beam door sensors, signal-type safety sensors, and 3D Hall motion detectors for enhanced passenger protection during emergencies such as power failures, fires, or earthquakes.

The Thyssenkrupp EVOLUTION MRL (Machine Room-Less) traction elevator at Manezh Square Exhibition Center in Moscow demonstrates modern elevator technology with a 1350kg capacity for 18 persons, featuring safety mechanisms like brakes and door locking systems, and operates at 1.0 m/s speed across 5 floors including basement levels.

This video demonstrates an MRL (Machine Room Less) elevator system in operation, showing the hoist motor, governor, Zenodine Zillbeg drive unit, brake chopper, and controller box working together; it illustrates how the counterweight moves downward as the lift car ascends, balancing the weight of the car and passengers to reduce energy consumption.