Selection of cabinets and busbars
Elements of the shop power supply
Workshop power supply, as a rule, is carried out at a voltage of up to 1 kV. Intrashop power supply networks differ significantly in configuration, design, and this depends on the number and power of the supplied receivers, their distribution on the shop floor plan, environmental requirements and production technology.
A huge amount of wire materials and switching equipment are laid in the electrical networks of the workshop, and the indicators of efficiency, reliability and safety of work depend on how competent the design was.
Distribution cabinets and busbar trunking, control boxes, screens, etc.
Distribution busbars
Shinny are used to power the electrical receivers of a technological line (for example, an assembly line), a concentrated large number of electrical receivers distributed in a group. For ease of use, bus channels are placed above the equipment, mounted on racks or on cables, at a height of 2.5-3 m.
Buses by design can be:
— open
— bus bars of insulators;
— protected
— open busbars protected by a net or box of perforated sheets;
— closed
— full tires.
The electrical receivers are connected to junction boxes evenly spaced along the length of the busbar.
Distribution cabinets and boxes
Electrical distribution cabinets are installed in the areas of the store for the distribution of electricity supplied on the supply lines between the groups of electricity consumers.
To control individual consumers of electricity, such as faucets, control boxes are installed.
These devices (power cabinets and control boxes) contain switching and protective equipment (switches, fuses, circuit breakers) designed to control electrical receivers with a voltage of up to 1 kV and protect them from short circuits and overloads.
The selection of power distribution cabinets and boxes is made depending on:
— nominal current of a group of electric receivers;
— the number of branches to be connected;
— values of peak currents of the links.
Selection of cabinets and busbars
Selection conditions:
1. Calculation <Inom,
where Icalc is the nominal current of a group of electric receivers; Inom is the nominal current of the distribution busbar (cabinet).
2. nep << span style = «font-size: 12pt;»> nsh
where nep is the number of electricity consumers in the group; nsh — the number of possible connections to the distribution bus (cabinet).
3. Iс3> Iс3,
where Ic3 — operating current of electrical equipment protection (electrical receivers); Iс32 — operating current of the protection installed in the cabinet (busbar box).
4. Izz1> In / a
where Ip is the initial current of the electric receiver; a — coefficient considering initial conditions: a = 2.5 — easy start; a = 1.6 … 2.2 — severe (long-term).