Global 5120 - Page 22

GlobalPowerTechnologies  2-7
5120
Figure 7 RatedGrossPowerofPowerUnitvs.AmbientTemperatureatBeginningofLife
To determine the required Set-up Power see graph in Figure 7 and consider the following
example:
1) Thepresentsitetemperatureis40ºC
2) Find40ºConthehorizontalaxis.
3) Readverticallyuntilintersectingtheratedpowercurve.
4) Readhorizontallytotheverticalaxistondtheset-uppower.
5) Whichis113Watts
V
set
,thevoltageacrosstheprecisionload,isameasureofpower.Thevalueoftheprecision
load(0.375ohm)isselectedtoprovidetheoptimumloadconditionfortheTEG.Therelation-
shipbetweenV
set
(V)andpower(P)is:
   P=(V
set
)
2
    0.375
ThisrelationshipisshowninFigure8.TodeterminetheratedV
set
seethegraphinFigure8:
1) Therequiredpoweris116Watts
2) Locate116Wattsonthehorizontalaxis.
3) Readverticallyuntilintersectingthecurve.
4) ReadhorizontallytotheverticalaxistodetermineratedV
set
.
5) Whichis6.6volts.