Compensation R&S®Hz186; Transformer Measurement; Mutual Inductance - Hameg R&S HM8118 Benutzerhandbuch

Measuring Equipment
The measurement adapter R&S®HZ186 is designed for
measurements of transformers or transmitters in combina-
tion with transformer measurement functions of the LCR
bridge R&S®HM8118. The measurement adapter is directly
connected to the front panel BNC connectors of the LCR
bridge via the four BNC sockets.
1 Transformer test adapter
2 Test lead for high number of windings
3 Test lead for low number of windings
Fig. 8.7: 4-wire transformer test lead
In case of a faulty measurement, the LCR bridge does not display
any value for N.
The 4-wire transformer test lead is a convenient tool to
measure the mutual inductance (M), the transformer ra-
tio (N) and the phase difference Θ in a frequency range
between 20Hz and 200kHz of a transformer or transmit-
ter. The measurement adapter serves as interface between
the LCR bridge and the four included test leads. For the
measurement, the transformer / transmitter to be measu-
red is connected to the measurement adapter via test lead,
according to the imprinted wiring on the primary and the
secondary side. This equipment is optional and is not in-
cluded in delivery.
Technical Data R&S®HZ186
Function: Measurement adapter to operate (via 4-wire
connection) with LCR bridge HM8118
Measurable components: Transformers, transmitters
Measurable parameters: Mutual inductance M (1 µH...100 H),
Transformer ratio N (0,95...500),
phase difference φ between primary and se-
condary winding (-180° to +180°)
Frequency range: 20 Hz to 200 kHz
Test lead length: approximately 35 cm
Connectors: BNC sockets (4), BNC connectors (4)
Safety standards: EN61010-1; IEC61010-1;
EN61010-031; IEC61010-031
Environmental conditions: Contamination Class 2, internal use
Operating temperature: +5° C to +40 °C
Storage temperature: -20 °C to +70 °C
Weight: approximately 240 g
8.3.1 Compensation R&S®HZ186
Due to their design, the test lead HZ186 and the connected
test leads have a fringing capacitance, self inductance and
self-resistance which impacts the accuracy of the measu-
62
red values. To minimize these impacts, the compensation
of impedance errors caused by adapters and leads beco-
mes necessary.
For frequency dependent components, make sure to perform
an OPEN and SHORT compensation for each of the 69 test
frequencies.
To compensate or eliminate this measurement error, it
1
is recommended to perform an open and short com-
pensation (OPEN/SHORT compensation) with the LCR
3
bridge R&S®HM8118. For the open compensation, the
2
2
four test leads are connected to the measurement adapter
R&S®HZ186. Before starting the open compensation, the
two black test leads (which are connected to the „COM-
MON" BNC connectors) are connected. It is also neces-
Für den „Kurzschlussabgleich" sind die beiden roten Mess-
sary to connect the two red test leads that are connected
leitungen und die beiden schwarzen Messleitungen gemein-
to the BNC connectors „N" and „1".
sam miteinander zu verbinden.
HAMEG HZ186 HAMEG HZ186
Fig. 8.8: OPEN / SHORT calibration with R&S®HZ186
Bild 2:
For the short compensation, the two red test leads and the
two black test leads are connected to each other.

8.3.2 Transformer Measurement

The measurement of a transformer can always result in va-
rying measurement results. This is related both to the iron
core losses as well as to the unknown state of the prema-
gnetized core. The component to be measured is depen-
dent on the frequency as well as on the applied measure-
ment voltage. The measuring instrument determines the
values for L, R and C by measuring the impedance and the
related phase angle. The angle determines an inductive,
capacitive or real value (L,C,R). Consequently, the amount
Bild 3 „Primär- und Sekundär Transformator"
of the impedance increases as the voltage increases, and
the phase angle is heavily dependent on the measurement
frequency (due to change in magnetization and iron core
loss and visible in the „Z-Theta" mode [7]). If a transformer
is measured as „open", the measurement values are plau-
sible. However, if the secondary side is short-circuited, it is
only possible to measure considerably fewer measurement
values. The values in case of a short-circuited secondary
page correspond nearly precisely to the core losses.
HAMEG HZ186

8.3.3 Mutual Inductance

To measure the mutual inductance, the R&S®HM8118 ap-
Bild 4 „Spar-Transformator"
plies the same procedure as for the regular inductance.
Instead of measuring the voltage via primary winding, the
voltage will be measured at the secondary transformer
winding.
OPEN-Abgleich = trennen
SHORT-Abgleich = kurzschließen
HAMEG HZ186
Short Circuit
kurzschließen
Open trennen
Short Circuit
kurzschließen
schwarz
Transformator
rot
Gemeinsamer
Masseanschluss
Spar-
Transformator
11
Änderungen vorbehalten