How many square wires do you need for five air conditioners

How many square wires do you need for five air conditioners

The input power of the 5-hp machine is about 4500W
It can be calculated according to I = P / u: I: current, P: power, u: voltage
4500W/220V=20.5A
Its maximum input current is about 20A
According to the current of 6A per square wire:
4 square x 6A = 24a
So to ensure safety, you can choose 4 square wires and 32A air switch!

Formula and derivation of fan ring surface area

Fan ring "surface area"... Fan ring is a plane figure... If you know the right center angle a (radian system), inner diameter R and outer diameter R, is the formula derived from (R ^ 2-r ^ 2) * (A / 2)... By product. The popular point is to regard the small change of each center angle as D. then each D has a very small area

How to deduce the fan ring area?
Please see clearly, what I asked is the fan ring, not the fan, the solution to the fan area, do not enter! The book says that s = π (R1 + R2) l, where R1 and R2 are the radii of the upper and lower bottom surfaces, and l is the length of the generatrix!
In fact, I want to find the side area of the frustum, because the side area of the frustum is a fan ring. As we all know, the area of the fan ring is a large fan area, and the fan area is reduced. However, the formula given in the book (above) is added after simplification. I don't know why?

Let R be the top bottom radius, R be the bottom radius, H be the height, l be the generatrix;
The arc length of the upper opening is 2 π R and that of the lower opening is 2 π R;
The expanded side view of a cone is a fan ring. Just like calculating the area of the cone side, the expanded side is transformed into a special "triangle". The area is the arc length of the bottom circle multiplied by the generatrix length and then divided by 2. So similarly, if the fan ring is transformed into a special "trapezoid", then the height of the "trapezoid" is the generatrix length L of the cone (note, not the height of the cone), According to the trapezoid area calculation formula, you can calculate the area of the side of the cone (trapezoid is the bottom and bottom oh)
S cone side = 1 / 2 (C ˊ + C) l = 1 / 2 (2 π R + 2 π R) l = π L (R + R)

The area formula of fan property and its derivation

For a sector, let the center angle of a sector be n ° and its radius be r. let its arc length be L. first, the relationship between its arc length L and the circumference C of the circle is investigated. The center angle of the circle opposite the circle is 360 ° and the circumference is 2 π R. The arc length of the sector is L = (360 ° / N °) × (2 π R); (1 / 2) l = (360 ° / n