Q.Please explain power loss of power supplies.

Power Supplies >  Switching Power Supply >  AC-DC Power Supplies/ DC-DC Converters

A. The power loss of power supplies is the difference between input active power and output power and is calculated with the formulas below.
Power loss= input active power - output power
Input active power can be calculated with the output power ÷ efficiency, so
power loss= (output power ÷ efficiency) - output power.

(example) When calculating the power loss in HWS1500-48 with the maximum output power when the input voltage Vin = 200VAC and the ambient temperature Ta = 25°C：
The power loss is as shown below because the efficiency is 90% of the specifications with the maximum output power (1536W).
Power loss = (1536W ÷ 0.9) - 1536W = 171W