What is the difference between efficiency and average efficiency?

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Efficiency

Energy provide datasheets embody product efficiency in a proportion format for every voltage and output power mannequin, as a steering to how a lot power is misplaced in wasted warmth when the product is operating.   As the precise working efficiency varies with enter voltage, output load, ambient temperature and part tolerance, normally there is a take a look at situation famous. 
Phrases like “as much as 95%” or “sometimes 93% at 230Vac enter, 100% load and 25oC ambient” are broadly used.
If the collection of the power provide is being made purely on efficiency, then the producer’s analysis knowledge must be studied with a purpose to decide the measured efficiency at the person’s load situation.  Determine 1 exhibits the efficiency vs. output present plot for TDK-Lambda’s 600W rated 24V output GXE600-24 for various enter voltages.  At 60% load, 230Vac enter one may anticipate the efficiency to be 94%.
Determine 1: GXE600-24 Efficiency vs Output Present
Average efficiency

Exterior power provides complying with the DoE (Division of Vitality) and EU efficiency laws will typically solely state the customary (and its revision) they adjust to.  TDK-Lambda’s DTM110PW240C8 datasheet for instance, states compliance with the newest DoE Degree VI & EU Tier 2 Efficiency requirements and additionally consists of that the average efficiency is >89%. The average efficiency for an external power provide rated between 49-250W must be at the very least 89% to adjust to the present and proposed requirements.

Is “Average Efficiency” the identical as “Efficiency”?  No.

Average efficiency is calculated by measuring the efficiency at 25%, 50%, 75% and 100% masses.  These 4 values are added collectively and the whole is divided by 4 to acquire the average. Measurements are taken at 115Vac and 230Vac inputs.

Utilizing the measurements from Determine 2 for the DTM110PW240C8, the calculated average efficiency at 115Vac is 90% and 90.5% at 230Vac.

--
Enter
Output
--
Load (%)
Energy
(W)
Voltage
(Vdc)
Present
(A)
Energy
(W)
Efficiency
(%)
Vin: 115V/50Hz
100
121.53
24.16
4.54
109.69
90.0
75
91.67
24.20
3.43
83.11
91.0
50
61.27
24.26
2.28
55.40
90.0
25
31.73
24.27
1.17
28.35
89.0
10
12.44
24.27
0.46
11.07
89.0
0
0.08
24.25
--
--
--
Vin: 230V/50Hz
100
119.33
24.16
4.52
109.07
91.0
75
92.19
24.21
3.47
83.87
91.0
50
62.11
24.27
2.30
55.83
90.0
25
30.74
24.34
1.14
27.63
90.0
10
13.26
24.35
0.49
11.82
89.0
0
0.11
24.25
--
--
--
Determine 2: DTM110PW240C8 Efficiency Measurements

Efficiency readings are additionally taken at 10% to examine compliance to the EU Tier 2 Efficiency customary.  For a power provide rated at 49-250W it will need to have a minimal efficiency of 79%.  At 10% load the DTM250-D has an efficiency of 89%.

Energy Man