ARMY TM 9-6115-60412NAVY NAVFAC P-8-633-12(3)Connect a 500 V dc megohmmeter to either primary lead, H1 or H2, and to ground. Operate themegohmmeter for 60 seconds and observe resistance. Reading should not be less than 1000megohms.(4)Connect the megohmmeter to either secondary load X1 or X4 and to ground. Operate themegohmmeter for 60 seconds and observe resistance. Reading should not be less than 1000megohms.(5)Connect the megohmmeter between the primary and secondary windings. Operate themegohmmeter for 60 seconds and observe the resistance. Readings should not be below aminimum of 250 megohms.(6)Refer to the next higher level of maintenance if VOLTAGE REGULATOR transformer T102 falls anytest procedure described above.(7)Reconnect wires and discard tags.4-142. GENERATOR INSTRUMENT TRANSFORMERS T104, T106, T107, AND BUS INSTRUMENTTRANSFORMERS T108 THROUGH T110. See Figure 3-26. The instrument transformers are 20 1 stepdowntransformers 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, ofthis 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 T108through Tl10 Perform the following steps on each transformer.(2)With multimeter set to RX1 scale, perform individual continuity checks on transformer primary andsecondary windings. The readings should be:primary winding ..................................122 ohmssecondary winding ..............................0.002 ohms(3)Connect a 500 V dc megohmmeter to either primary lead and to ground Operate the megohmmeterfor 60 seconds and observe resistance Reading on each transformer should be not less than 20megohms.(4)Connect the megohmmeter to either secondary lead and to ground. Operate the megohmmeter for60 seconds and observe resistance Reading should be not less than 1 megohm.(5)Connect the megohmmeter between the primary and secondary windings. Operate themegohmmeter for 60 seconds and observe the resistance. Reading should not be less than 20megohms.(6)Refer any instrument transformer that fails any of the above test procedures to the next higher levelof maintenance.(7)Reconnect wires and discard tags.4-202
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