MIL-DTL-16036M(SH)
3.15.3 Instrument transformers.
3.15.3.1 Transformers for metering and relaying. Instrument transformers for metering and relaying shall
conform to MIL-I-1361 having an accuracy for Navy secondary standard rating. Transformer type of devices used
to provide phase angle for single-phase wattmeters on three-phase circuits or similar functions shall conform to
MIL-I-1361. Instrument transformers provided for voltage regulators shall not be used to supply any other burden.
For each group of instruments, relays and synchroscope, one set of instrument transformers shall be used unless the
burden on one set would be too great for the accuracy required. Potential transformers for each group of
instruments, relays, and synchroscope shall not be used for other potential devices. Where two potential
transformers are used for three-phase operation, they shall be connected open delta on the primary and secondary.
One transformer shall be connected across phase A-B and the other across B-C. Where current transformers are
required to supply three-phase current, two transformers shall be used, one connected in phase A, one in phase C.
Their secondaries shall be connected open delta. Current transformer secondary circuits that extend beyond the
section containing the current transformers shall be provided with protective devices conforming to MIL-I-1361 to
prevent high voltage in the event of an open circuit. Protective devices shall be connected so that their operation
will not shunt out protective relays that may be connected in the circuit. A short circuiting switch shall be connected
in parallel with the protective device for manually short circuiting the remote part of the current transformer circuit.
Connections shall be as shown on figure 20. Current transformer secondary circuits, which supply both metering
and electric governor input, shall be wired so that when the metering test receptacle cover is removed, the current
transformer secondary is short circuited through the electric governor so that performance of the electric governor
will be unaffected. Current transformers shall not be used as bus bar supports.
3.15.3.2 Grounding of secondary terminal. One secondary terminal of each metering and relaying (potential
and current) transformer shall be grounded, except for the following:
a. For three-phase connections where one ground connection shall be made to the common or B phase of the
two transformers.
b.
For current and potential transformers used in voltage regulator circuits.
3.15.4 Inductive relays. Inductive relays, both protective and auxiliary types, shall conform to MIL-R-2033
and shall be of types that have been tested for Class A high-impact shock. Auxiliary relays shall be in accordance
with MIL-DTL-2212 and MIL-R-19523. Solid-state relays shall be in accordance with MIL-PRF-28750. Relays
used in the circuit breaker control circuits shall be selected so that under switchboard shock they will not cause the
circuit breakers to change state.
3.15.5 Transformers. Transformers shall conform to MIL-T-15108 and MIL-T-16315, as applicable.
3.15.6 Resistors and rheostats. Resistors and rheostats shall conform to MIL-DTL-15109. Power dissipation
shall not exceed 50 percent of the rated value after ambient temperature and other applicable derating factors are
applied in accordance with the part specification.
3.15.7 Reverse power monitor. Reverse power monitors shall be in accordance with MIL-M-24350.
3.16 Indicator lights. Whenever possible, indicator lights shall be Light Emitting Diode (LED) type. If an
LED type indicator light is not available for a particular application, an incandescent type indicator light may be
used. LED indicator lights shall be in accordance with A-A-59781. Incandescent indicator lights shall conform to
MIL-DTL-3661, MIL-L-3661/38, MIL-L-3661/62, MIL-L-3661/63, MIL-L-3661/64, and MIL-L-3661/65, as
applicable. Indicator lights shall be furnished with lamps. For position indication of circuit breakers, blue indicator
lights shall be used to show that the circuit breaker is closed. Other indicator lamps have color caps as specified for
the particular application. The color code shall be as follows:
a.
Red
-
danger or emergency condition requiring immediate attention or corrective action.
b.
Green
-
normal condition.
c.
White
-
power available or power on.
d.
Blue
-
closed, advisory.
e.
Clear (not etched)
-
synchronizing or ground detector lights.
f.
Yellow
-
abnormal, but not requiring immediate attention.
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