UFC 3-570-06
JANUARY 31 2003
batteries installed internally, or with an external DC power source through a panel plug.
7-3.6.2
Manually Synchronizable Interrupter. This unit is similar to a high quality
conventional interrupter (may be accurate to within one tenth of a second in 24 hours)
with the additional feature of synchronizing the interruption cycle with other like units.
This is normally accomplished by using a supplied cable to temporarily connect two
units together, to start second, third, fourth, etc., units for synchronization of the
interruption cycles of all units. These units make it possible to interrupt several rectifiers
simultaneously to use various instruments to measure an instant-OFF potential reading.
They are usually portable, but could possibly be installed equipment, with a portable
unit used to synchronize the rectifier-installed units.
7-3.6.3
Advanced Synchronizable Interrupter. These units are similar to a
manually synchronizable interrupter with the means of synchronization controlled by
some communication technology (versus manually by cable connection) such as radio,
computer connection, modem, or satellite transmissions. They are usually permanently
installed, but portable units are also available.
7-3.6.4
Pulse Generator. The pulse generator can normally be used as a
conventional current interrupter or as a standard pulse generator. They may be
permanently or temporarily installed in the rectifier cabinet. They do not require
synchronization when used together with the proper waveform analyzing equipment. If
used for a conventional current interrupter, they are not synchronizable, but usually
provide for user-selectable interrupt cycles. The standard pulse generator is connected
in series in the DC output (either positive or negative) of the rectifier(s) and produces a
precisely timed, zero-current pulse that does not drift. AC supply voltage is used to
power the pulse generator. Selectable input AC power units must be set for the correct
AC supply voltage being used. Ensure the pulse generator is set to the proper voltage
before applying AC power, or the pulse generator will be damaged.
7-3.7
Specific Methods for Various Instant-OFF Potential Measurement
Techniques
7-3.7.1
Using Normal Digital Voltmeter with Current Interrupter(s). The digital
voltmeter may be used together with a current interrupter to measure an instant-OFF
potential. For locations that are affected by more than one rectifier or DC current
source, synchronized interruption must be accomplished. For locations that are
affected by more than three to six rectifiers or DC current sources (according to their
contribution or availability of synchronizable interrupters), subsequent systems can be
turned off to preclude their contribution to the instant-OFF reading.
7-13
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