Crane electrical equipment. Trolleys up to 1 kV

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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
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Section 5. Electric power plants

Crane electrical equipment. Trolleys up to 1 kV

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Encyclopedia of radio electronics and electrical engineering / Rules for the installation of electrical installations (PUE)

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5.4.17. The repair section of the main trolleys must be electrically isolated by means of insulated joints from the continuation of the same trolleys and connected to them by means of disconnecting devices so that during normal operation this section can be energized, and when the crane is stopped for repairs, it is reliably disconnected.

The insulation of the joints of the main trolleys must be made in the form of an air gap, the width of which depends on the design of the current collector, but must be at least 1 mm at voltages up to 50 kV. The width of the current collector must be such that during normal operation of the crane, interruptions in the supply of voltage and its unexpected stop when the current collector crosses the insulated joints of the trolleys are excluded.

The disconnecting devices used to connect the repair area with the continuation of the main trolleys must be of a closed type and have a device for locking in the off position.

5.4.18. The repair section of the main trolleys, located at the end of the crane span, must be equipped with one insulated joint and one disconnecting device.

The repair section of the main trolleys, located in the middle of the span, must be equipped with two insulated joints (one on each side) and three disconnecting devices, switched on in such a way that it is possible to provide continuous power supply to the trolleys, bypassing the disconnected repair section, and also disconnect them separately as repair site, as well as sections of trolleys located on both sides of it.

5.4.19. The length of the repair section of the main trolleys, located at the end of the crane span, must be at least the width of the crane bridge plus 2 m, and the length of the section located in the middle of the span must be at least the width of the crane bridge plus 4 m.

If an electric hoist (hoist) is installed to repair the crane, then the length of the repair section should be determined depending on the extreme positions of the bridge during repair:

1. At the repair site at the end of the crane span, at least 2 m should remain from the insulated joint to the bridge, which occupies the position furthest from the end during repair.

2. At the repair site in the middle of the span, there should be at least 2 m from the insulated joints to the bridge in all possible positions during the repair.

5.4.20. On the main trolleys, and in the case of their sectioning, on each section of these trolleys and on each of their repair sections, it should be possible to install a jumper that shorts each other and grounds all phases (poles) for the period of inspection and repair of the trolleys themselves or repair of the crane.

5.4.21. The main trolleys and trolleys of the crane must be carried out in accordance with the requirements of Ch. 2.2 and this chapter.

5.4.22. For small-sized trolley conductors, the requirements of Ch. 2.2, as well as 5.4.23, 5.4.24, 5.4.26, 5.4.39 and the second paragraph of 5.4.17 do not apply.

5.4.23. The main trolleys of the crane should, as a rule, be made of steel. It is allowed to make these trolleys from aluminum alloys. The use of copper and bimetal for main trolleys and crane trolleys must be specifically justified.

5.4.24. Trolleys can be rigid or flexible; they can be suspended on cables and placed in boxes or channels. When using rigid trolleys, it is necessary to provide devices for compensating linear changes from the temperature and settlement of the building.

5.4.25. The distances between the attachment points of the trolleys must be such as to exclude the possibility of short circuits between them and on grounded parts. This distance is selected taking into account the sag, and in the open air - in addition, taking into account the deflection of the conductor under the action of the wind.

5.4.26. For cranes with voltage up to 660 V, installed both indoors and outdoors, the clear distances between any current-carrying parts of trolleys of different phases (poles), as well as between them and other structures that are not isolated from the ground, must be at least 30 mm for parts that are stationary relative to each other and 15 mm for parts that move relative to one another. At voltages above 660 V, these distances must be at least 200 and 125 mm, respectively.

The specified distances must be provided for the main trolleys of the crane with all possible movements of the crane, its trolley, etc.

5.4.27. The distances from the main trolleys and crane trolleys to the floor level of the workshop or the ground must be at least: at voltages up to 660 V - 3,5 m, and in the roadway - 6 m; at voltages above 660 V - in all cases 7 m. Reducing the indicated distances is allowed provided that the trolleys are fenced (see 5.4.31 - 5.4.33).

With flexible trolleys, the indicated distances must be ensured with the largest sag.

5.4.28. When laying trolleys in the floor in channels covered with concrete slabs or metal sheets, as well as in boxes located at a height of less than 3,5 m, the gap for moving the bracket with current collectors should not be in the same vertical plane with the trolleys.

Trolley boxes must be made in accordance with the requirements given in Ch. 2.2.

In the channels located in the floor, it is necessary to ensure the drainage of soil and process water.

5.4.29. The flexible cable used to power the electrical equipment of the crane, in places where damage is possible, must be suitably protected. The choice of cable brand should be made taking into account the conditions of its operation and possible mechanical influences.

5.4.30. The main trolleys of the bridge type crane should be placed on the side opposite to the location of the control cabin. Exceptions are allowed in cases where the main trolleys are inaccessible to accidental contact from the control cabin, from landing sites and ladders.

5.4.31. The main trolleys and their current collectors must be inaccessible to accidental contact from the crane bridge, stairs, landing areas and other areas where people may be. This should be ensured by their appropriate location or fencing.

5.4.32. Appropriate protective devices must be installed in places where the cargo ropes may come into contact with the trolleys of this crane or a crane located a tier below.

5.4.33. Crane trolleys and their current collectors, which are not automatically switched off, must be fenced or located between the crane bridge trusses at a distance inaccessible to the personnel servicing the crane. Trolley fencing should be carried out along the entire length of the trolley and from the ends.

5.4.34. In areas where ice formation on zip lines is possible in the open air, devices or measures should be provided to prevent or eliminate ice.

5.4.35. The line supplying the main trolleys up to 1 kV must be equipped with a closed-type switch, designed to turn off the operating current of all cranes installed in one span. The switch must be installed in a place accessible for shutdown and turn off the trolleys of only one span.

If the main trolleys have two or more sections, each of which is powered by a separate line, then sectional shutdown of the trolleys is allowed with the adoption of measures that exclude the possibility of voltage being applied to the disconnected section from other sections.

The circuit breaker, and in case of remote control - the circuit breaker control device, must have a locking device in the off position, as well as a position indicator: "On", "Off".

5.4.36. For cranes that operate in heavy and very heavy duty, it is recommended to protect the line supplying the main trolleys up to 1 kV with a circuit breaker.

5.4.37. The main trolleys must be equipped with a light signaling of the presence of voltage, and when sectioning the trolleys and the presence of repair sections, each section and each repair section must be equipped with this signaling.

It is recommended to directly connect signaling devices to the trolleys, in which the lamps glow when there is voltage on the trolleys and go out when it disappears. With three-phase current trolleys, the number of signaling lamps must be equal to the number of phases of the trolleys - one lamp switched on for each phase, and with DC trolleys, the signaling device must have two lamps connected in parallel.

To ensure the durability of the lamps, measures must be taken (for example, the inclusion of additional resistors) to reduce the voltage at their terminals by 10% of the nominal value under normal conditions.

5.4.38. Connection of extraneous power receivers to the main trolleys of magnetic cranes, cranes transporting liquid metal, as well as other cranes, during the operation of which a power failure can lead to an accident, is not allowed.

5.4.39. Rigid type main trolleys must be painted except for their contact surface. The color of their coloring should differ from the color of the building structures and crane beams, and red color is recommended. In the place of power supply on a length of 100 mm, the trolleys must be painted in accordance with the requirements of Ch. 1.1.

5.4.40. To supply voltage to the flexible cable of portal electric cranes, columns specially designed for this purpose must be installed.

See other articles Section Rules for the installation of electrical installations (PUE).

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