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Safety Rules

EUROPEAN STANDARD EN 81-1: 1998 English version Safety rules for the construction and installation Part 1: Electric lifts The National Standard of the People`s Republic of China [ Safety rules for the construction and installation of electric lifts ]

GB 7588 2003 eqv EN 81-1: 1998


12 Lift machine


12.1 General provision

Each lift shall have at least one machine of its own.


12.2 Drive of the car and the counterweight or balancing weight


12.2.1 The following two methods of drive are permissible:
a) by traction (use of sheaves and ropes) ;
b) by positive drive, i.e. :
1) either use of a drum and ropes, or
2) use of sprockets and chains.
The rated speed shall not exceed 0,63 m/s. Counterweights shall not be used. The use of a balancing weight is permitted.

The calculations of the driving elements shall take into account the possibility of the counterweight or the car resting on its buffers.


12.2.2 Use may be made of belts for coupling the motor or motors to the component on which the electro-mechanical brake (12.4.1.2) operates. In this case a minimum of two belts shall be used.


12.3 Use of overhung pulleys or sprockets

Devices according to 9.7 shall be provided.


12.4 Braking system


12.4.1 General provisions


12.4.1.1 The lift shall be provided with a braking system, which operates automatically:
a) in the event of loss of the mains power supply ;

b) in the event of the loss of the supply to control circuits.



12.4.1.2 The braking system shall have an electro-mechanical brake (friction type), but may, in addition, have other braking means (e.g. electric).


12.4.2 Electro-mechanical brake


12.4.2.1 This brake on its own shall be capable of stopping the machine when the car is
traveling downward at rated speed and with the rated load plus 25 %. In these conditions the retardation of the car shall not exceed that resulting from operation of the safety gear or stopping on the buffer.
All the mechanical components of the brake which take part in the application of the braking action on the drum or disk shall be installed in two sets. If one of the components is not working a sufficient braking effort to slow down the car, traveling downwards at rated speed and with rated load shall continue to be exercised.

Any solenoid plunger is considered to be a mechanical part, any solenoid coil is not.


12.4.2.2 The component on which the brake operates shall be coupled to the traction sheave or drum or sprocket by direct and positive mechanical means.


12.4.2.3 To hold off the brake, in normal operation, shall require a continuous flow of current.


12.4.2.3.1 The interruption of this current shall be effected by at least two independent electrical devices, whether or not integral with those, which cause interruption of the current feeding the lift machine.

If, whilst the lift is stationary, one of the contactors has not opened the main contacts, further movement of the car shall be prevented at the latest at the next change in the direction of motion.


12.4.2.3.2 When the motor of the lift is likely to function as a generator, it shall not be possible for the electric device operating the brake to be fed by the driving motor.


12.4.2.3.3 Braking shall become effective without supplementary delay after opening of the brake release circuit.

NOTE : The use of a diode or capacitor connected directly to the terminals of the brake coil is not considered as a means of delay.


12.4.2.4 Any machine fitted with a manual emergency operating device (12.5.1) shall be

capable of having the brake released by hand and require a constant effort to keep the brake open.


12.4.2.5 The brake shoe or pad pressure shall be exerted by guided compression springs or weights.

12.4.2.6 Band brakes shall not be used.



12.4.2.7 Brake linings shall be incombustible.


12.5 Emergency operation


12.5.1 If the manual effort required to move the car in the upward direction with its rated load does not exceed 400 N the machine shall be provided with a manual means of emergency operation allowing the car to be moved to a landing with the aid of a smooth, spokeless wheel.


12.5.1.1 If the wheel is removable, it shall be located in an easily accessible place in the
machine room. It shall be suitably marked if there is any risk of confusion as to the machine for which it is intended.

An electric safety device in conformity with 14.1.2 shall be actuated when the wheel is put on the machine at the latest.


12.5.1.2 It shall be possible to check easily from the machine room whether the car is in an unlocking zone. This check may be made, for example, by means of marks on the suspension or governor ropes.



12.5.2 If the effort defined in 12.5.1 is greater than 400 N, a means of emergency electrical operation from the machine room shall be provided in accordance with 14.2.1.4.


12.6 Speed

The speed of the lift car, half loaded, in downward motion, in mid-travel, excluding all acceleration and retardation periods, shall not exceed the rated speed by more than 5 %, when the supply is at its rated frequency, and the motor voltage is equal to the rated voltage of the equipment 8).


This tolerance is also applicable for the speed in the case of :
a) leveling (14.2.1.2 b)) ;
b) re-leveling (14.2.1.2 c)) ;
c) inspection operation (14.2.1.3 d)) ;
d) emergency electrical operation (14.2.1.4. e)) ;

e) docking operation (14.2.1.5 c)).


12.7 Stopping the machine and checking its stopped condition

The stopping of the machine by means of an electric safety device, in conformity with 14.1.2, shall be controlled as detailed below.


12.7.1 Motors supplied directly from A.C. or D.C. mains

The supply shall be interrupted by two independent contactors, the contacts of which shall be in series in the supply circuit. If, whilst the lift is stationary, one of the contactors has not opened the main contacts, further movement of the car shall be prevented at the latest at the next change in the direction of motion.


12.7.2 Drive using a Ward-Leonard system


12.7.2.1 Excitation of the generator supplied by classical elements
Two independent contactors shall interrupt, either :
a) the motor generator loop, or
b) the excitation of the generator, or
c) one the loop and the other the excitation of the generator.
If, whilst the lift is stationary, one of the contactors has not opened the main contacts, further movement of the car shall be prevented, at the latest at the next change in direction of motion.

In cases b) and c) effective precautions shall be taken to prevent the rotation of the motor in the case of a residual field, if any, in the generator (e.g. suicide circuit).


12.7.2.2 Excitation of the generator supplied and controlled by static elements
One of the following methods shall be used :
a) the same methods as specified in 12.7.2.1 ;
b) a system consisting of :
1) a contactor interrupting the excitation of the generator or the motor generator loop.
The coil of the contactor shall be released at least before each change in direction of motion.
If the contactor does not release, any further movement of the lift shall be prevented, and
2) a control device blocking the flow of energy in the static elements, and
3) a monitoring device to verify the blocking of the flow of energy each time the lift is
stationary.
If, during a normal stopping period, the blocking by the static elements is not effective, the
monitoring device shall cause the contactor to release and any further movement of the lift shall be prevented.

Effective precautions shall be taken to prevent the rotation of the motor in the case of a residual field, if any, in the generator (e.g. suicide circuit).


12.7.3 A.C. or D.C. motor supplied and controlled by static elements
One of the following methods shall be used:
a) two independent contactors interrupting the current to the motor.
If, while the lift is stationary, one of the contactors has not opened the main contacts, any

further movement shall be prevented, at the latest at the next change in direction of motion ;


b) a system consisting of :
1) a contactor interrupting the current at all poles.
The coil of the contactor shall be released at least before each change in direction. If the
contactor does not release, any further movement of the lift shall be prevented, and
2) a control device blocking the flow of energy in the static elements, and
3) a monitoring device to verify the blocking of the flow of energy each time the lift is

stationary.


If, during a normal stopping period, the blocking of the flow of energy by the static elements is not effective, the monitoring device shall cause the contactor to release and any further movement of the lift shall be prevented.
12.7.4 Control devices according to 12.7.2.2 b) 2 or 12.7.3 b) 2), and monitoring devices
according to 12.7.2.2 b) 3) or 12.7.3 b) 3) need not to be safety circuits according to 14.1.2.3.
These devices shall only be used provided the requirements of 14.1.1 are met to achieve

comparability to 12.7.3.a).


12.8 Monitoring the normal slowdown of the machine in case of reduced buffer stroke


12.8.1 In the case of 10.4.3.2, devices shall check that the slowdown is effective before arrival at terminal landings.


12.8.2 If the slowdown is not effective these devices shall cause the car speed to be reduced in such a way that, if the car or the counterweight comes into contact with the buffers, the striking speed shall not exceed that for which the buffers were designed.


12.8.3 If the device checking the slowdown is not independent of the direction of travel, a device shall check that the movement of the car is in the intended direction.


12.8.4 If these devices, or some of them, are placed in the machine room :
a) they shall be operated by a device directly coupled to the car ;
b) the information relating to the car position shall not depend on devices driven by traction, friction, or by synchronous motors ;
c) if a connection by tape, chain or rope is used to transmit the position of the car to the

machine room, breakage of or slack in such a connecting device shall cause the machine to stop through the action of an electric safety device in conformity with 14.1.2.



12.8.5 The control and functioning of these devices shall be so designed that together with the normal speed regulation system there results a slowdown control system complying with the requirements of 14.1.2.


12.9 Safety devices against slack rope or slack chain

Positive drive lifts shall have a slack rope/chain device actuating an electric safety device in conformity with 14.1.2. This device may be the same as the one required in 9.5.3.


12.10 Motor run time limiter


12.10.1 Traction drive lifts shall have a motor run time limiter causing the de-energizing of the machine, and keep it de-energized, if :
a) the machine does not rotate when a start is initiated ;

b) the car/counterweight is stopped in downwards movement by an obstacle which causes the ropes to slip on the traction sheave.


12.10.2 The motor run time limiter shall function in a time which does not exceed the smaller of the following two values:
a) 45 s;

b) time for traveling the full travel, plus 10 s, with a minimum of 20 s if the full travel time is less than 10 s.


12.10.3 The return to normal operation shall only be possible by manual resetting. On restoration of the power after a supply disconnection, maintaining the machine in the stopped position is not necessary.


12.10.4 The motor run time limiter shall not affect the movement of the car under either the inspection operation or the emergency electrical operation.


12.11 Protection of machinery
Effective protection shall be provided for accessible rotating parts, which may be dangerous, in particular:
a) keys and screws in the shafts ;
b) tapes, chains, belts ;
c) gears, sprockets ;
d) projecting motor shafts ;
e) fly-ball type overspeed governors.
Exception is made for traction sheaves with protections according to 9.7, handwinding wheels, brake drums and any similar smooth, round parts. Such parts shall be painted yellow, at least in part.

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