Relationship between busbar layout and current carrying capacity

Relationship between busbar layout and current carrying capacity

 

The current carrying capacity of the busbar is higher than that when it is placed horizontally. Generally, when the busbar is laid flat and the width is less than 60㎜, the current carrying capacity is 0.95 times that of the vertical bus, and when the width is greater than 60㎜, the current carrying capacity is the vertical 0.92 times, this is because the heat dissipation performance when standing is better than when laying flat.

3.3 Carrying capacity value

According to the different materials of the bus, the current carrying capacity is also different at the same temperature. In the switchgear and control equipment, the rectangular copper bus bar is the main rectangular aluminum bus bar. Its current carrying capacity value can generally be found according to various design manuals. Based on many years of experience, the author summarizes the simple calculation formula of the busbar current carrying capacity (AC) when standing upright through the statistics of the busbar current carrying capacity in various manuals.

Current carrying capacity Id(A) of single-layer rectangular copper busbar at 40℃:

Id = k (b+8.5) h

In the formula, b is the thickness of the busbar (mm); h is the width of the busbar (mm); k is the coefficient (A/mm).

The relationship between the current-carrying capacity of the double-layer copper busbar and the single-layer busbar at 40℃

I2=(1.56～1.58) Id

In the formula, I2 is the current carrying capacity (A) of the double-layer copper bus; Id is the current carrying capacity (A) of the single-layer copper bus Bus duct manufacturers. 1.56～1.58 is the coefficient, generally 1.58 for 100×10 bus; 1.57 for 80×10, 1.57 for 60×6, and 1.56 for 60×6.

The relationship between the current carrying capacity of the 3-layer copper busbar and the single-layer copper busbar at 40℃ is:

I3=2Id

In the formula, I3 is the current carrying capacity of the four-layer copper busbar (A).

At 40℃, the relationship between the current carrying capacity of the 4-layer copper busbar and the single-layer copper busbar is (this type of option is not recommended, it is best to use a special-shaped busbar instead)