Equipment
Use
Manufacturer
Oscilloscope, Type 531 (or
Tektronix, Portland, Oregon
To monitor transducer output waveforms.
equal)
Vibration Test Equipment,
MB Manufacturing Co., New
To provide controlled vibration for calibration
Model C11 (Vibration Table)
Haven, Conn.
of the transducer.
(or equal)
Vacuum Tube Voltmeter,
Hewlett-Packard Co., Palo
To measure driving voltage applied to the
Model 400H (or equal)
Alto, Calif.
vibration table and transducer output voltages.
Leeds and Northrup,
Wheatstone Bridge, Model
To measure resistance of transducer coils.
5305 (or equal)
Chicago, Ill.
Weston Electrical Instrument
Insulation Tester, Model
To measure electrical leakage.
779 (or equal)
Corp., Newark, N. J.
1-62. MAINTENANCE INSTRUCTIONS, VIBRA-
connector. Reading on the bridge test set should be
TION TRANSDUCER TYPE 4-118-0107
as specified in the calibration record (between 770
AND TYPE 4-128-0101.
ohms and 850 ohms for the Type 4-118-0107, and
between 441 ohms and 539 ohms for the Type 4-128-
1-63. TEST EQUIPMENT REQUIRED. Required test
0101).
equipment for testing and maintenance of the vibra-
tion transducer is listed in figure 1-29.
quency of the transducer as follows:
1-64. PERIODIC INSPECTION. Inspect the vibration
a. Install the vibration transducer on a vibration
transducer carefully after each use for evidence of
table as shown in figure 1-33.
damage to the case. Check the electrical connector
b. Connect the output of the transducer to the ver-
for bent terminals and evidence of corrosion. Check
tical input of an oscilloscope.
that the four screws attaching the cover to the bobbin
a s s e m b l y (or coil and pole piece assembly) are
c. Connect the output of the vibration table signal
tightened securely.
generator to the horizontal input of the oscilloscope.
1-65. TROUBLESHOOTING. If the vibration trans-
d . With the transducer at 77 oF, set the vibra-
ducer fails to operate properly, most troubles can
tion table to vibrate at approximately 20 cps with a
be rapidly isolated by referring to the troubleshoot-
velocity of 2 in./sec. Vary the frequency of vibration
ing chart in figure 1-30 or figure 1-31.
until a 90 phase shift is observed on the oscillo-
scope (as indicated by a reversal in direction of tilt
of the lissajous pattern on the oscilloscope screen).
This phase shift will occur within 2 cps of the
a. Connect an insulation tester across pins 1 and 3
nominal natural frequency. The natural frequency
should be approximately 15 cps for the Type 4-128-
tester must be above 0.1 megohm at 45V dc for the
0101 and 30 cps for the Type 4-118-0107.
Type 4-128-0101, and above 100 megohms at 45V dc
for the Type 4-118-0107.
1-69. FREQUENCY RESPONSE TEST. With the
transducer installed on a vibration table in a vertical
b. Connect an insulation tester across pins 2 and 3
position as shown in figure 1-34, read and record the
output of the transducer at each of the vibration table
tester must be above 0.1 megohm at 45V dc for the
settings listed in figure 1-35. Monitor the output wave-
Type 4-128-0101, and above 100 megohms at 45V dc
forms of both the transducer and the vibration table
for the Type 4-118-0107.
during each test. The test results must be as follows:
Transducer Output
Mv
Sensitivity =
1-67. COIL RESISTANCE TEST. Connect a Whets-
Vibration Table Drive
In./Sec
tone Bridge across pins 1 and 2 (figure 1-32) of
