Use
Equipment
Manufacturer
Energizes magnet assembly.
Charging Coil, Model HB-19154
Radio Frequency Laboratories,
Inc. , Boonton, N.J.
(or equal)
Adjusts sensitivity.
Radio Frequency Laboratories,
Magnetreater, Model 889B
Inc. , Boonton, N.J.
(or equal)
Radio Frequency Laboratories,
Knock-down coil for adjusting sensitivity,
Magnet Standardizing Coil, Part
No. HC-7010-16 (or equal)
Inc. , Boonton, N.J.
Radio Frequency Laboratories,
Energizes magnet assembly.
Magnet Charger, Model 2470
Inc. , Boonton, N.J.
(or equal)
c. Set the CHARGING VOLTAGE LEVEL switch to
place the magnet assembly and sleeve for the
position 2. Press the ENERGIZE button and wait
Type 4-128-0101, or the magnet for the Type
until the voltmeter indicates approximately 100 volts.
4-118-0107.
Press CHARGE button.
1-94. CALIBRATION PROCEDURE. Calibration of
d. Repeat the procedure described in step c , allow-
the magnet assembly consists of reducing the level
ing approximately 50 volts increase for each cycle
of the magnetic charge to obtain a sensitivity of
until the voltage build-up has reached 300 volts. At
60 2 mv/in./sec for the Type 4-128-0101 or 105 5
this point, the magnet assembly in the transducer
mv/in./sec for the Type 4-118-0107. Perform the
will be completely saturated.
calibration as follows:
e. Remove the vibration transducer from the magnet
a. Mount the vibration transducer in a vertical posi-
charger.
tion on a vibration table. Connect the vibration trans-
ducer and the test equipment as shown in figure 1-34.
NOTE
Energizing the magnet assembly using 50-volt
b. Operate the vibration table at 100 cps with a
steps as described above, reduces the force of
velocity of 2 in./sec/rms. Calculate and record the
impact with which the magnet hits its stops
transducer output in mv/in./sec.
during the field transient. The charging time
for low voltage is usually between 1 and 4
c. Connect the Magnet Standardizing Coil, Part No.
seconds.
HC-7010-16 to the Magnetreater Model 889B, and
place over the vibration transducer.
f. The sensitivity range of the Type 4-128-0101
Vibration Transducer, when the magnet assembly is
d. Set the pulse rate at position 1 or 2.
completely saturated, is between 65 and 72 mv/in./sec
NOTE
(vertical), when the transducer is vibrated at 100 cps
at a velocity of 2 in./sec/rms. For the Type 4-118-
The pulse rate may be increased when use of
0107, the sensitivity range of the vibration transducer
the magnetreater becomes familiar.
is between 180 and 240 mv/in./sec when magnet
assembly is completely saturated and vibrated at
e. Adjust the coarse control by starting from zero
100 cps at a velocity of 2 in./sec/rms.
and increasing until the output of the transducer indi-
cates a slight drop on the readout meter. Adjust the
NOTE
fine control until output of the transducer reaches
If the fully saturated sensitivity is below the
the desired sensitivity level on the readout meter.
required sensitivity stated in f , the magnet
NOTE
assembly may not be properly charged, or it
may be defective. Repeat the charging proce-
dures described in steps a through f at least
If the sensitivity is dropped below the desired
twice. If the fully saturated sensitivity is still
sensitivity, re-energize the magnet assembly
below the required sensitivity stated in f, re-
and repeat the calibration procedure.
