Hioki ST4030, Instruction Manual, Page: 15 / 256

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Overview
1.1 Overview
Windings (workpieces) found in motors, coils, and other components are
covered with insulation, but the insulation resistance may fall and short
circuits occur between proximate layers for some reason. The condition is
called a “layer short circuit”.
The ST4030, ST4030A Impedance Winding Tester not only compares and
judges waveform conformance through comparisons with existing response
waveforms, but also detects layer short circuits using judgment methods
that employ the rendering of response waveforms as numerical values (LC
and RC values). Further, incorporating the ST9000 Discharge Detection Upgrade (optional) into
the instrument enables highly precise detection of partial discharges that occur in the stages in
advance of a layer short circuit.
1.2 Features
High-speed and high-resolution sampling
Sampling using 200 MHz, 12 bit resolution enables the detection of minute changes in the response
waveform that hitherto could not be seen. In this way, it is possible to detect layer short circuits with
a high level of accuracy compared to before.
Numerical rendering of impulse response waveforms (LC and RC values)
The equivalence circuits for the impulse test are viewed as LCR linear equivalent circuits, and the
response waveforms are rendered numerically into LC and RC values. Rendering the response
waveforms into numerical values enables the response waveforms to be judged quantitatively.
Further, the data can be managed more easily than the waveform data.
Impulse can be tested with the rotor mounted
With the rotor and motor stator mounted, the stray capacitance between the rotor and the stator
changes depending on the rotor angle.
Changes in the stray capacitance also change the impulse response waveform, so judgments are
difficult using existing waveform comparison methods.
Numerical judgment values using LC and RC values can create PASS judgment area from the LC
and RC values distribution, and so by creating PASS judgment area using a healthy phase, it is
possible to test the impulse with the rotor mounted.
High-precision Discharge Detection Upgrade
Extracting the high-frequency discharge components of the response waveform enables highly
precise detection of partial discharges, which have hitherto been difficult to detect using flutter
operations and Laplacian operations.
High waveform reproducibility
The applied voltage variation is small, so it is possible to detect defective products accurately.
Further, the instrument differences when the same workpiece is tested are small, so it is possible to
use the master workpiece data as is even if the instrument is replaced.
Reference: “15.5 Repeat Accuracy (Reference Value)” (p. 230)
Easy-to-use interfaces and an abundance of interfaces
The screen uses 8.4-inch color TFT crystals with touch panel for easy viewing and intuitive
operability. Compatible with various usage scenarios using external control (EXT. I/O), USB
memory, USB devices, and LAN. Further, RS-232C or GP-IB can be added as options.
1 Overview
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Overview