In the design and manufacture of cranes, HEZ PTM LLC uses two fundamentally different approaches. The first approach is based on the requirements of the “Soviet” standards and GOSTs – all components and mechanisms of the crane are selected based on the fact that the crane, without taking into account wearing parts, must work out the entire standard life. The second approach is “European” – the components and mechanisms installed on the crane are subject to full or partial replacement during the standard period of operation of the crane during the development of their resource.
Based on the first “Soviet” approach, HEZ PTM LLC produces high-quality KMOs that should be operated in workshops where a rail is used as a way to move the crane.
The single-girder overhead traveling crane consists of:
- device for lifting and moving loads.
- span beams.
- two end beams.
- crane management and energy systems.
As a device for lifting and moving cargo, a hoist of the corresponding carrying capacity, lifting height, operating mode and speeds required by the customer is used. As a rule, HEZ PTM LLC recommends using the hoist of one of the Bulgarian manufacturers. The span beam manufactured by HEZ PTM LLC for KMO is welded from 09G2s steel with a lower cargo belt along which the hoist moves. The end beams manufactured by KHEZ PTM LLC are of box section, welded from 09G2s steel, for the convenience of maintenance and repair, have a boxen wheel assembly (as on “Soviet” cranes). As a crane drive, a gear motor designed for the entire standard life of the crane is used. To prevent dynamic shocks from the transported load and prevent swaying, frequency control of the drives is set in the control cabinet with IP-54 electrical protection.
The customer can order:
- radio control.
- outdoor lighting.
- hard current lead.
- pendant control
- coloring of the crane.
Depending on the technological purpose of the crane beam and electric motors installed on the mechanisms, various control systems are used:
- When applied to all mechanisms of single-speed electric motors, control is carried out according to the scheme with direct connection.
- When using two-speed electric motors on the hoist and hoist mechanisms, the electric motors of the crane movement are controlled from the frequency converter.
In direct-drive electric circuit designs, thermal and maximum current protection of all electric motors are provided. An electric drive based on a frequency converter provides the following types of protection:
- protection against overheating of electric motors;
- motor overload protection;
- protection against short circuits between phases;
- earth fault protection;
- phase failure protection;
- engine rollover protection;
- overheating protection of power elements of converters.
All control systems provide protection against excessive lowering of the supply voltage and the disappearance of one of the phases.
The crane is controlled in two ways:
- from a suspended control post that can move along with the hoist, move along the span beam.
- through a radio channel from a portable control panel of the RADEL-DU system, manufactured by HEZ PTM LLC.
All electrical equipment assembled on an elemental base of Schneider Electric. It is placed in the control box with a degree of protection of the shell not lower than IP54. The power supply of the crane control system is carried out from an alternating current network 380V, 50Hz. It is possible to order electrical equipment for other power standards.