There are two solutions to comply with the A3:
a) Use safety components.
b) Use the drive machine.
In spite of the fact that the Standard allows the use of the machine and its associated electronics to prevent uncontrolled car movements (UCM), it is certain that the UCM cannot be prevented if it occurs due to suspension ropes sliding. In order to achieve both detecting and controlling the UCM completely and safely, Dynatech recommends the safety components’ solution.
a) Possibilities to comply with A3 by using the safety components:
a.1- Using safety components with A3 certificate independently:
Our safety gears and governors (STAR, VEGA, QUASAR T-25 and QUASAR SV) are certified in accordance with A3 as independent components.
The A3 certificates of these components are included in their corresponding manuals for use and maintenance. Please find below which said products are in case you wish to download their manuals:
BIDIRECTIONAL PROGRESSIVE SAFETY GEARS:
- PR-2500-UD V35
- PR-2500-UD V50
UNIDIRECTIONAL PROGRESSIVE SAFETY GEARS:
Dynatech’s unidirectional progressive safety gears also have an A3 certificate since their construction, along with their features, coincide with that of their bidirectional equivalents. Nevertheless, having this certificate is irrelevant since a UCM control can only be performed with a bidirectional safety gear.
BIDIRECTIONAL OVERSPEED GOVERNORS:
- QUASAR T-25
- QUASAR SV
According to Amendment 3, the car must stop if an uncontrolled movement occurs. This stop must occur at a maximum distance below 1 m (among other requirements).
Dynatech’s governors incorporate a system, called Anti-creep System, used to lock the governor when a UCM (uncontrolled car movement) is detected. When the governor locks, the safety gear is activated. From the moment the car moves until it stops, the total distance must be below 1 m.
-Before continuing reading the following explanation, please read the UCM section included in the governors’ manuals where the anti-creep system’s functioning is explained.
Obtaining the A3 certificates for independent components does not exempt the installer from performing the uncontrolled movements tests included in the EN 81:A3 standard on site. Examples:
The customer purchases the components independently, for example, our overspeed governor but not the safety gear, which is purchased from another manufacturer. In this option, the customer must compile the safety gear and the governor’s certificates; then, he/she must perform validation tests of the UCM solution in its installation. Furthermore:
>>a. The customer may purchase the electronics managing the anti-creep system from the manufacturer.
>>b. The controllers’ manufacturer manages the anti-creep system by using the electronics already built-in his/her controller.
Note: Managing the anti-creep system has to do with the warnings specified in the governor’s manual (UCM section).
a.2- Using the safety components with A3 certificate as a whole:
The customers purchase the Safety gear + Governor + anti-creep management electronics package.
This package is A3 certified as UCM solution. By using this solution, the customer does not have to follow all the processes to check whether the governor + safety gear comply with the A3’s margins and requirements, as well as the management of signals for the anti-creep system.
Differences between using what stated in items a.1 and a.2.Advantages and Disadvantages
In case a.1, the customer must ensure that the “marriage” between governor and safety gear complies with A3, apart from performing the tests with the control system, either using the electronics supplied by the governors’ manufacturer or that built-in the controller. This will mean additional costs.
On the other hand, by using this option, the customer may choose the component that best fits him/her, either for price, versatility or for any other reason.
In case a.2, the customer does not have to worry about whether the governor + safety gear comply with A3 or not. He/she will only have to perform the usual commissioning tests according to the standard.
However, the customer may have the disadvantage of not being able to combine different components from different manufacturers, which may make him/her gain versatility or competiveness.
Nevertheless, Dynatech recommends always using the safety components of the same manufacturer since the responsibility for good functioning and for the safety of the assembly falls on a single person.
Dynatech offers the corresponding electronics, called D-BOX, in order to complete the safety when detecting and controlling the UCM.
The D-BOX is an electronic device governing the governor’s anti-creep system used for the UCM solution. This device may be used both with the Vega and Star governors, but may also be used with governors of other brands.
For further information on the features and requirements, please download the manual from our website.
a) Possibilities to comply with A3 by using the drive machine:
Our drive machines (Tornado) are certified for the A3 solution.
According to what is stated in section 9.11 of the A3, the means used to stop the uncontrolled movement may be those acting on the traction sheave or shaft. The A3 allows using the motor’s brakes for this purpose:
9.11.3: If the machine brake is used, the auto-control may include the verification of the correct raising or lowering of the mechanism, or the verification of the braking force. Should a failure be detected, the next normal lift’s start-up must be prevented.
Dynatech has designed two devices, called CDC (Car Drag Control) to manage the anti-creep system and BFS (Brake Failure Surveillance) to manage the motor brakes used to stop a UCM.
The entire unit (Tornado + BFS + CDC) complies with the A3 and has its own certificate. The customer does not need an extra certificate.
Its manual may be downloaded from our website.
This explanatory article will be updated as more products, their developments or innovations relating to this matter are added.
Updated information note on everything relating to EN81’s 3 Amendment