The meaning of BF and BK in the electrical low-voltage wiring system diagram is as follows:
1, BK means control lighting transformer, such as BK-500VA indicates that the transformer capacity of 500VA. transformer is used as a control circuit in electrical equipment, as well as used as a signaling lamps, indicators and low-voltage safety lamps power supply;
2, BF circuit breaker brand model. Such as circuit breaker BFM6/1P, that the circuit breaker is 1P.
Low-voltage power distribution system consists of distribution substations (usually to reduce the transmission voltage of the grid to the distribution voltage), high-voltage distribution lines (i.e., more than 1 kilovolt voltage), distribution transformers, low-voltage distribution lines (less than 1 kilovolt voltage), and the corresponding control and protection equipment.
Expanded information:
The way to look at the electrical low-voltage wiring system diagram:
1, look at the steps of the main circuit
2, look at the electrical equipment in the main circuit. Electrical equipment refers to the consumption of electrical appliances or electrical equipment, look at the map first to see clearly there are several electrical appliances, their categories, uses, wiring and some different requirements.
3, to find out what electrical equipment is used to control electrical components. There are many ways to control electrical equipment, some directly with the switch control, some with a variety of starter control, some with contactor control.
4, understand the main circuit used in the control appliances and protection appliances. The former refers to other control elements in addition to conventional contactors, such as power switches (transfer switches and air circuit breakers), universal transfer switches.
The latter refers to short-circuit protection devices and overload protection devices, such as air circuit breakers in the electromagnetic release and thermal overload release specifications, fuses, thermal relays and overcurrent relays and other components of the use and specifications. Generally speaking, the main circuit for the above content of the analysis, you can analyze the auxiliary circuit.
5, look at the power supply. To understand the power supply voltage level, is 380V or 220V, from the busbar busbar power supply or distribution screen power supply, or from the generator set out.
Baidu Encyclopedia - Low-voltage wiring system