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Subchapter 4. Construction Safety Orders
Article 14. Construction Hoists
§1604.24. Operating Devices and Control Equipment.
(a) Operation and Operating Devices.
(1) Types of Operating Devices. All operating devices shall be of the enclosed electric type. Rope or rod operating devices actuated directly by hand, or rope operating devices actuated by wheels, levers, or cranks, shall not be used.
(2) Operating Devices for Car-Switch Operation Hoists.
Handles of lever-type operating devices of car-switch operation hoists shall be so arranged that they will return to the stop position when the hand of the operator is removed. Car-switch push-buttons shall be of the constant-pressure type so that when the hand is removed from the button the car will stop.
(3) Top-of-Car Operation During Inspection, Maintenance, Repair, Tower Erection and Dismantling.
(A) When persons are on top of a car for the purposes of inspection, maintenance, repair, tower erection or dismantling, the car shall be operated by a competent authorized operator using car top operating devices. In addition, during inspection and maintenance the car shall be operated only in the slowest speed.
(B) Car top operating devices shall conform to the requirements of subsection (a)(2), and be installed in such a manner that the in-car operating devices are not functional when car top operation is selected. The car top operating devices shall include an emergency stop button, conforming to the requirements of Section 1604.24(b)(4) that when activated will stop the car at any point of travel.
(C) Car top operating devices shall be so located and arranged to prevent inadvertent exposure of the operator to hazards of contact with moving counterweights and stationary elements of the hoist tower, tower tie-ins, or adjacent structure.
(D) The tops of cars shall be enclosed by a standard guardrail and toeboard meeting the specifications of Section 3209 of the General Industry Safety Orders except that for the purposes of this subsection, the area between the car top and the midrail may be filled with screen material with maximum openings that will reject a 3/4 inch diameter ball.
(b) Electrical Protective Devices.
Electrical protective devices shall be provided in accordance with the following requirements:
(1) Slack-Rope Switch.
Hoists having winding-drum machines shall be provided with a slack-rope device equipped with a slack rope of the enclosed manually reset type which shall cause the electric power to be removed from the hoist driving-machine motor and brake if the hoisting ropes become slack.
(2) Motor-Generator Running Switch.
Where generator-field control is used, means shall be provided to prevent the application of power to the hoist driving-machine motor and brake unless the motor-generator-set connections are properly switched for the running condition of the hoist. It is not required that the electrical connections between the hoist driving-machine motor and the generator be opened in order to remove power from the hoist motor.
(3) Motor-Field Excitation Switch.
Where generator-field control is used, a motor-field excitation switch shall be provided which shall cause the electric power to be removed from the hoist driving-machine motor and brake unless current is flowing in the shunt-field circuit of the hoist driving-machine motor.
(4) Emergency Stop Switch.
An emergency stop switch shall be provided in the car and located in, or adjacent to, the car operating pane. When opened, this switch shall cause the electric power to be removed from the hoist driving machine motor and brake. Emergency stop switches shall have the following characteristics:
(A) They shall be of the manually opened and closed type.
(B) They shall have red operating handles or buttons.
(C) They shall be conspicuously and permanently marked “STOP.”
(D) They shall be positively opened mechanically and their opening shall not be solely dependent on springs.
(5) Broken-Rope, Tape, or Chain Switches Used in Connection with Machine-Room Normal-Terminal Stopping Switches.
Broken-rope, tape, or chain switches shall be provided in connection with normal-terminal stopping devices located in machine rooms of traction hoists. Such switches shall be opened by a failure of the rope, tape, or chain.
(6) Car-Safety-Mechanism Switch.
A switch conforming to the requirements of Sections 1604.19(f), 1604.20(d)(1), and 1604.20(d)(3) shall be required where a car safety is provided.
(7) Speed-Governor Overspeed Switch.
A speed-governor overspeed switch shall be provided when required by Section 1604.20(d)(1) and shall conform to the requirements given under Sections 1604.20(d)(2) and 1604.20(d)(3).
(8) Final-Terminal Stopping Devices.
Final-terminal stopping devices conforming to the requirements given under Section 1604.23(c) shall be provided.
(9) Terminal Speed-Limiting Devices.
Where reduced-stroke oil buffers are provided or car rated speed exceeds 300 feet per minute, emergency terminal stopping devices conforming to the requirements given under Section 1604.23(d) shall be provided.
(10) Compensating-Rope Sheave Switch.
Compensating-rope sheaves, when used, shall be provided with a compensating-rope sheave switch or switches mechanically opened by the compensating-rope sheave before the sheave reaches its upper or lower limit of travel, to cause the electric power to be removed from the elevator driving-machine motor and brake.
(11) Primary Magnetic Switch.
A primary magnetic contactor shall be provided for main power disconnect, in addition to the normal service disconnect switch as required by Section 1604.24(d). The primary magnetic contactor shall perform its power disconnect function upon any interruption of the final-terminal stopping devices and all other electrical safety devices.
(12) Car Door or Gate Electric Contacts.
Car door or gate electric contacts conforming to the requirements given under Section 1604.18(b) shall be provided for all hoists.
(13) Normal-Terminal Stopping Devices.
Normal-terminal stopping devices conforming to the requirements given under Section 1604.23(b) shall be provided for every hoist.
(14) Motor-Generator Overspeed Protection.
Means shall be provided to cause the electric power to be removed automatically from the hoist driving-machine motor and brake should a motor-generator set, driven by a DC motor, overspeed.
(c) Voltages Permitted in the Hoistway or on the Car.
The maximum system or circuit potential permitted on any equipment in the hoistway or on the car shall not be more than 440 volts (nominal). Where the potential exceeds 120 volts, a grounding conductor shall be incorporated in the traveling cable. The type and size of the grounding conductor and the grounding fastening means shall conform to the requirements of the Electrical Safety Orders.
Exception: Installations provided with an inherent grounding system for the car.Installations provided with an inherent grounding system for the car.
(1) The nominal rated system or circuit potential for all circuits, in locations other than those specified, shall not exceed 600 volts except for driving motors of motor-generator sets.
(d) Supply-Line Disconnecting Means.
A fused-disconnect switch or a circuit breaker shall be installed and connected into the power-supply line to each elevator motor or motors or to the motor of the motor-generator set. Disconnect switches or circuit breakers shall be of the manually closed multi-pole type arranged to be locked in the open position and their location shall conform to the requirements of the Electrical Safety Orders.
Disconnect means for hoists having a DC primary power supply and rheostatic control shall have the disconnect switch arranged so that its opening will directly open the driving-machine brake circuit.
Where circuit breakers are used as a disconnecting means, they shall not be of the instantaneous type and shall not be opened automatically by a fire alarm system.
(e) Phase-Reversal and Failure Protection.
Hoists having polyphase AC power supply shall be provided with means to prevent the starting of the hoist motor if the phase rotation is in the wrong direction, or there is a failure of any phase.
This protection shall be considered provided in the case of generator-field control having AC motor-generator driving motors, provided a reversal of phase will not cause the hoist driving-machine motor to operate in the wrong direction. Controllers whose switches are operated by polyphase torque motors provide inherent protection against phase reversal or failure.
(f) Devices to Make Electrical Protective Devices Inoperative.
The installation of condensers, the operation or failure of which will cause an unsafe operation of the hoist, is prohibited. No permanent device shall be installed, except as provided in this Standard, which will make any required electrical protective device inoperative.
(g) Driving Machine Brakes.
Driving machine brakes shall not be electrically released until power has been applied to the driving machine motor.
All power feed lines to the brake shall be opened, and the brake shall apply automatically when the following conditions prevail:
(1) The operating device of a car switch or continuous pressure operation hoist is in the stop position.
(2) A floor stop device functions.
(3) Any of the electrical protective devices function.
Under conditions (1) and (2) above, the application of the brake may occur on or before the completion of the slowdown and leveling operations.
The brake shall not be permanently connected across the armature or field of a DC hoist driving-machine motor.
(h) Control and Operating Circuit.
In the design and installation of the control and operating circuits, the following requirements shall be met:
(1) Springs shall not be used to actuate switches, contactors, or relays to break the circuit to stop the hoist.
(2) The completion or maintenance of an electric circuit shall not be used to interrupt the power to the hoist driving-machine motor or brake at the terminal landings, nor to stop the car when the emergency stop switch is opened or any of the electrical protective devices operate.
Exception: The requirements of Section 1604.24(h)(2) do not apply to dynamic braking or to speed control switches.The requirements of Section 1604.24(h)(2) do not apply to dynamic braking or to speed control switches.
(3) The failure of any single magnetically operated switch, contactor, or relay to release in the intended manner, or the occurrence of a single accidental ground, shall not permit the car to start or run if any hoistway door interlock is unlocked or if any hoistway door or car door or gate contact is not in the closed position.
(4) Where generator-field control is used, means shall be provided to prevent the generator from building up and applying sufficient current to the hoist driving-machine motor to move the car when the hoist motor control switches are in the “off” position. The means used shall not interfere with maintenance of an effective dynamic braking circuit during stopping and standstill conditions.
(i) Absorption of Regenerated Power.
Where a power source is used which, in itself, is incapable of absorbing the energy generated by an overhauling load, means of absorbing sufficient energy shall be provided on the load side of each hoist power supply-line disconnecting means to prevent the hoist from attaining governor-tripping speed or a speed in excess of 125% of rated speed, whichever is less.