User manual
42 GMC-I Messtechnik GmbH
Measurements: V/Hz, , , Temp (°C/°F), , M
@UISO
, A/Hz
5.8 Interturn Short-circuit Measurement – Function
COIL/M
@UISO
This function can only be performed with the METRAHIT COIL de-
vice variant and only in combination with the COIL TEST ADAPTER.
With this measurement, a partially periodic time value is deter-
mined in proportion to the inductivity of the respective winding for
each motor coil or coil combination via a cyclical discharge at high
voltage. A comparison of the measurement results allows for ex-
amining the symmetry of the motor coils and the detection of a
potential interturn short-circuit as a result.
5.8.1 Preparing the Measurement
Note
Interturn short-circuit measurements may only performed on
voltage-free windings.
➭ Connect the
COIL TEST ADAPTER
with the two enabled jacks of
the multimeter via the contact-protected plugs at the adapter
connection cables: the red cable with the COIL jack and the
black cable with the COM jack.
➭ Set the rotary switch at „
COIL/M
@UISO
“.
➭ Connect the two measurement cables with the two jacks of
the
COIL TEST ADAPTER
(marked with a motor symbol).
➭ Establish contact between the inductive DUT and the (alligator)
clips applied to the test probes. In the case of 3-phase current
motors, for example, contact the winding connections U–V, V–
W und U–W successively.
➭ An interference voltage measurement V AC+DC TRMS is con-
ducted in this switch position.
Only if the DUT is voltage-free, are you allowed to press key U
COIL
ON / OFF for interturn short-circuit measurement (and hold it until
the measured value is stable).
COM mA A
V
Tem p
MISO
0V !
!
M
@UISO
V
1M
COIL
V
U
W
Example
COIL
METRAHITCOIL
COIL
COIL
TEST ADAPTER
Star Connection
M
Connect COIL TEST ADAPTER
and Measuring Cables
UISO
1200 V !
> 500 A !
(Pulse)
M
@UISO
V
Interference Voltage Detection
000.0
V
DC
AC
TRMS
1M
1000V
COIL