How to calculate Heat Dissipation of PLC ?

[Lancie1]

Ahmed,

It is not a simple calculation to find the fan size. After much experience, you can do it by estimation. But to size the fan mathematically, you have to know how much heat must be removed, the temperature inside the cabinet, the ambient air temperature outside the cabinet, and the cooling characteristics of the fan.

Or you can look it up in a fan manufacturer's table of recommended fan sizes.

 

[Lancie1]

Misunderstanding here, power can be modified but never be created.....

100% of the power consumed is converted to heat at 100% efficiency

The "power consumed" in a transformer IS converted to heat, where the power not consumed is simply passed on to a downstream user, so yes, indeed there is room for a lot of mis-understanding.