MAINTENANCE
Gentherm Global Power Technologi
es
Page 62
7.
Measure the Voltage across Terminals 1 and 2 and record.
8.
Calculate the internal resistance using the equations 3 and 4 below.
9.
Check the internal resistance, Ri, is less than 0.375 W. If not, the power unit may be
damaged.
Equation 3
Equation 4
Where:
R
i
=
Internal resistance (W)
V
oc
=
Momentary open circuit voltage (V)
V
L
=
Load voltage (V)
I
L
=
Load current (A)
R
L
=
Precision load resistance (OHM)
V
set
=
Voltage measured across terminals 5 and 6 (V)
Example
If the load voltage and momentary open circuit voltages were measured
as 6.7 V and 12.2 V respectively and the precision load resistance was
0.375 OHM then:
I
L
= 1.25 (V
L
/ R
L)
= 1.25 (5.361/0.375)
= 17.87 A
R
INT
= (V
oc
- V
L
) / I
L
= (12.2-6.7) / 17.87
= 5.5 / 17.87
= 0.308 OHM
Internal resistance is acceptable, < 0.308 OHM.
For further information or assistance, please contact the Customer Service Department at
Gentherm Global Power Technologies.
Summary of Contents for P-5100
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