Dynalyzer – High Voltage Unit
OPERATION MANUAL
15
waveform may be viewed on a conventional scope. The scale factor is 0.5 V/10 kVp
(20000:1 ratio). The reduced scale factor is needed to prevent saturation of the amplifier.
The individual outputs are provided to allow checking transformer balance, or for use
where multi-channel plug-in scopes are available for viewing all available data, or where
the operator wishes to switch between dual trace and the add/invert mode (allowing the
summation to occur at the scope).
Figure 7:
Series Connection with Oscilloscope or Digital Voltmeter
Measurement Procedures for mA and mAs using Oscilloscope
This unit provides a unique means for viewing and measuring the current waveform in an x-ray
generator. Interpretation may require some analysis on the part of the user. In general it will be
found that three-pulse (constant potential) current measurements can be easily obtained from the
oscilloscope trace while single-phase measurements will require some calculation.
A storage oscilloscope, or oscilloscope camera will significantly aid in analyzing single-phase
measurements.
Three-Phase Current Measurements (using Oscilloscope)
Current measurements in three-phase equipment may be read directly from the oscilloscope trace.
Figure 8 shows a typical three-phase current waveform. By visual inspection, the average value
may be read from the oscilloscope trace. The scale factor is 1 millivolt per milliampere. Through
practice, the average area of ripple above and below the estimated current value should be equal.
The x-ray tube is an emission limited device. Normally, the peaks of the current waveform have a
lower slope than the voltage waveform and therefore the ripple in the current will be smaller than
the ripple in the three-phase voltage.
-
+
OR
OSCILLOSCOPE
DIGITAL VOLTMETER
+
X-RAY
TUBE
-
TUBE
CATH
GEN
GEN
ANODE
ANODE
TUBE
ANODE
TRANSFORMER
CATHODE
CABLES
VOLTAGE
5 FT HIGH
CABLES
EXISTING
CABLES
RG-58U
