Type 7512-1 Spike Injection Probe —Since it
is possible to pass the test cable through the
window of the injection probe, it is not a split
construction, but it is a complete toroid fitted
with a BNC connector. The core used in this
probe has been specially selected to adequately
transmit the low and high frequency components
of the required spike waveform. The inside
diameter of the injection probe is 1.25", suitable
for most cable diameters. Because it is necessary
to feed the cable through the window of the
probe, the connector on the cable must be
less than 1.25" diameter or the connector must
be removed before inserting the cable through
the probe.
Type 7519-1 Pulse Shaping Network — The
waveform of Model 6254-5S, Model 7054-1 and
Model 8282-1 (in 10 S mode) Spike Generators
decays to zero in approximately 10 microseconds.
Since the waveform of Figure 15(b) for compo-
nent number one is longer, the basic waveform is
stretched by the 7519-1 network at the expense
of rise time and amplitude. However, the genera-
tors have sufficient range in peak amplitude to
overcome the loss and the slightly lengthened
rise time is still within the requirements. The
shaping network and the injection probe have
each been designed so that short circuit current
of 10 amperes flows through the cable under test.
This is achieved at a generator setting which
delivers 50 volts when the cable under test
is open circuited at the receptor end.
Type 7541-1 Spike Receptor Probe — The
receptor probe is assembled with a hinged
construction allowing it to be placed around
the cable under test. The design of this probe
includes a calibrating resistor mounted in
the housing. This resistor has been adjusted so
that the display on the associated oscilloscope
accurately indicates the value of spike current
detected. The vertical amplitude in volts/cm
is converted to amperes/cm by multiplying
the displayed peak value by a factor of ten.
The waveshape displayed on the oscilloscope
should be similar to the requirement specified
in Figure 15(b) of specification MF0004-002,
decaying to zero in approximately 100 to 120 S.
Application Information
CABLE INDUCED TRANSIENTS
FOR SPACE SHUTTLE PROGRAM
The design requirements for electrical equipment
on board the Space Shuttle vehicle include cable
induced currents, called “indirect lightning
effects” as described in Rockwell International
Specification MF0004-002. A system for providing
“component number one” described in Figure
15(b) of that specification has been developed
and includes three items as follows:
Type No. Description
7512-1 Spike Injection Probe
7519-1 Pulse Shaping Network (for
use with Model 6254-5S,
Model 7054-1 or Model 8282-1
Spike Generator)
7541-1 Spike Receptor Probe
(calibrated for use with
oscilloscope)
The test method described in paragraph 4.2.7.2
and Figure 16 of the specification requires two
probes which are torodial transformers using
the cable under test as the coupling between
them.The injection probe and the receptor probe
are different in character and cannot be used
interchangeably.When using the Model 6254-5S
or 7054-1 or the 8282-1 (in 10 S mode) Spike
Generator as the signal source, it is necessary to
modify the shape of the pulse to comply with the
waveform shown in Figure 15(b). The 7519-1
Pulse Shaping Network is used between
the spike generator and the injection probe to
provide the appropriate waveform. The block
diagram on the back of this page depicts the
arrangement. A brief description of the three
ancillary items follows:
77
(2 pages)
Manymanuals.com
Manymanuals.de
Manymanuals.fr
Manymanuals.it
Manymanuals.pl
Manymanuals.cz
Manymanuals.es
Manymanuals-pt.com
Comments to this Manuals