Voltech AT360, Руководство пользователя

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T
ESTS AND
T
EST
C
ONDITIONS
P
AGE
7-26 V
OLTECH
AT
I
U
SER
M
ANUAL
7.1.6 QL – Q
UALITY
F
ACTOR
Measurement
Range
Test
Voltage
Test
Frequency
Basic
Accuracy
0.001 to 1000 1mV To 5V 20Hz To 3MHz 0.5%
When a transformer is energized, the changing magnetic field in the core
causes two types of losses: hysteresis losses and eddy current losses.
The total of these losses can be represented on the equivalent circuit of a
transformer by a resistance associated with the inductance of the
winding.
For this equivalent circuit the Quality Factor Q is defined as:
Q =
ω ω ω ω
Ls (
where
ω ω ω ω
= 2
ππππ
f)
Rs
For a given inductance, the lower the equivalent series resistance, the
higher is the value of Q, i.e. the 'better' the coil.
Where Used
The Q factor test would normally be used for signal, pulse and switched mode
power transformers, where the normal operating conditions require only small
excursions of the B-H curve, never extending beyond the linear region.