Hioki 3541 - Appendix 5 JEC 2137-Compliant Resistance Measurement; Of Inductive Machines

175
Appendix 5 JEC 2137-Compliant Resistance Measurement of Inductive Machines
Standard JEC 2137 specifies the determination of resistance values
according to the following formula:
Transforming Formula 1 provides the following:
............. Formula 2
On the other hand, Formula 3 shows the temperature correction
process with the 3541.
So the temperature coefficient to be set is determined as shown in
Formula 4.
............................ Formula 3
............................................. Formula 4
For example, if the reference temperature is 20°C, set the temperature
coefficient for the instrument as follows.
[ppm/deg]
Appendix 5 JEC 2137-Compliant Resistance
Measurement of Inductive
Machines
R
t
R
R
t
T
t
R
k+
t
T
k+
-------------
×=
...................................... Formula 1
R
t
R
Winding resistance at reference temperature t
R
R
tT
Measured value of winding resistance at t
T
t
0
Reference temperature [°C]
t
T
Temperature of winding during measurement [°C]
k Constant (235 for copper wire)
R
t
R
R
t
T
-------
t
R
k+
t
T
k+
-------------
1
1
1
t
R
k+
-------------
t
T
t
R
–()+
-------------------------------------------==
R
t
R
R
t
T
1 α
t
R
+ t
T
t
R
–()×
------------------------------------------=
α
t
R
1
t
R
k+
-------------=
α
t
R
1
t
R
k+
-------------
1
20 235+
--------------------- 3922== =