MW1008P, user manual
20
Default primary voltage is 230V. To change to 115V, press key
Menu
.
The second line presents the 2 available options. Press
the key below 115 to select virtual primary voltage of
115V. The brackets will move around 115. Press key
EXIT to go back to parameters Vs/Vp and to display the
secondary voltage for 115V this time.
M+
Mutual
inductance
and
primary/secondary phase shift The mutual inductance is obtained by measuring
primary current and secondary voltage of the transformer. This direct method
can lack of precision at highest frequencies because to parasitics elements of
the transformer. In case of capacity overflow, the message OVERFLOW is
displayed. If so, change impedance range by pressing key
Hold/Range
. It is
better to start with the lowest range and then increase range until getting a
result. The automatic mode should not be used for this function.
The calculation of the mutual inductance
can also be done by measuring the
inductance resulting from serializing 2
windings, by connecting them in the 2
possible configurations as shown on the
figure.
The M value is then :
M = (L
a
-L
b
)/4. The results from the 2
methods can be compared.
About mutual inductance :
When 2 winding are close to each other, the flux created by one can establish in the
second. The mutual inductance coefficient is the ratio of the flux produced by coil 1 in
coil 2 to the current that flows through coil 1.
