MI 3250 MicroOhm 10A
Measurement
33
Note about thermal EMF:
A junction between two different metals produces a voltage related to a
temperature difference (thermocouple). MicroOhm 10A eliminates the thermal
EMF effect by measuring resistance in both directions I+ and I-.
5.2.4 Inductive Mode
Inductive mode makes a single unidirectional measurement. It is intended for measuring
resistance on inductive objects. Depending on the size of the inductive object, testing
times could be very short for small objects or very long for the larger, high inductive
objects.
Before the desired current (for testing purpose) can flow, this energy requirement must
be met (
2
2
1
I
L
W
).
The range and current output is user defined.
Inductive measurement I/t plot
t
I
ADC
t
u
t
Test
+I
Start
Stop
t
c
t
d
Figure 5.8: Inductive Mode
t
c
.................. charging time (depends on the size of the inductor).
t
d
................. discharging time (same as the charging time or max 5min).
Note:
The Inductive Mode can be primarily used for measuring:
Motor & generator winding
Power transformers
Power inductors
Wire and cable resistance
Warnings:
Do not touch the test object during the measurement or before it is fully
discharged! Risk of electric shock!
When a resistance measurement has been performed on an inductive
object, automatic discharge may not be done immediately!
High voltage can appear on test terminals when measuring inductive
object!
