ARMY TM 9-6115-60412
NAVY NAVFAC P-8-633-12
(3)
Connect a 500 V dc megohmmeter to either primary lead, H1 or H2, and to ground. Operate the
megohmmeter for 60 seconds and observe resistance. Reading should not be less than 1000
megohms.
(4)
Connect the megohmmeter to either secondary load X1 or X4 and to ground. Operate the
megohmmeter for 60 seconds and observe resistance. Reading should not be less than 1000
megohms.
(5)
Connect the megohmmeter between the primary and secondary windings. Operate the
megohmmeter for 60 seconds and observe the resistance. Readings should not be below a
minimum of 250 megohms.
(6)
Refer to the next higher level of maintenance if VOLTAGE REGULATOR transformer T102 falls any
test procedure described above.
(7)
Reconnect wires and discard tags.
4-142. GENERATOR INSTRUMENT TRANSFORMERS T104, T106, T107, AND BUS INSTRUMENT
TRANSFORMERS T108 THROUGH T110. See Figure 3-26. The instrument transformers are 20 1 stepdown
transformers that furnish voltage input for the various generator control, metering, and fault protection circuits.
Dangerous voltage levels may be present at components located within cabinet C.
Observe all applicable safety precautions as outlined in Chapter 1, Section III, of
this manual.
a.
Test. The following test procedures apply for generator instrument transformers T104, T106, and T107;
and bus instrument transformers T108, T109, and T110.
(1)
Tag and disconnect all wiring from transformers T104, T106, and T107; and transformers T108
through Tl10 Perform the following steps on each transformer.
(2)
With multimeter set to RX1 scale, perform individual continuity checks on transformer primary and
secondary windings. The readings should be:
primary winding ..................................122 ohms
secondary winding ..............................0.002 ohms
(3)
Connect a 500 V dc megohmmeter to either primary lead and to ground Operate the megohmmeter
for 60 seconds and observe resistance Reading on each transformer should be not less than 20
megohms.
(4)
Connect the megohmmeter to either secondary lead and to ground. Operate the megohmmeter for
60 seconds and observe resistance Reading should be not less than 1 megohm.
(5)
Connect the megohmmeter between the primary and secondary windings. Operate the
megohmmeter for 60 seconds and observe the resistance. Reading should not be less than 20
megohms.
(6)
Refer any instrument transformer that fails any of the above test procedures to the next higher level
of maintenance.
(7)
Reconnect wires and discard tags.
4-202
