Development and manufacturing of non-
destructive testing units and system
Steel Structure Analyzer
NOVOTEST KRC-M2
5.2.2. Cycle of measurements includes stages:
- magnetic preparation;
- compensation of residual magnetization;
- calculation of the coercive force;
- indication of the measurement result.
5.2.3. During magnetic preparation, the area of tested product which
is between the pole pieces of the magnetic system of probe, are
periodically magnetized up to saturation of current pulses with
amplitude not less 2.0 A. Then is performed an automatic
compensation of residual magnetization field. From the value of the
magnetic field compensation current is automatically calculated
value of the coercive force.
5.2.4. The probe is a magnetic system which is closed with tested
product. Null indicator of the magnetic field is a Hall sensor. There
are coils at the probe, which are used for magnetization of tested
objects and compensation the field of residual induction.
The device implements a compensation method of measurement.
When you press the "Measure" key, begins the first sub-cycle of
measurement (magnetization). Through coils is supplied
magnetizing current. In the magnetic system is appears a field with
magnetic intensity which enough for fullness magnetization of tested
product. After magnetization, starts the second subcycle of
measurement (compensation). The compensation circuit is a circuit
with negative feedback, which is consist of null indicator of magnetic
field (Hall sensor), measuring coil, amplifier and power source. The
current, which flows through the coil of demagnetization,
compensation the magnetic flux of the residual magnetization of
tested product to zero, which is monitored with the null indicator of
magnetic field. The value of current in coil of demagnetization, which
is fixing, is proportionately to the coercive force of tested area of
