184.108.40.206 Current transformers. Current transformers for metering and
relaying shall be in accordance with MIL-I-1361, shall have a Navy classifica-
tion accuracy NSS, and shall be H.I. resistant. Transformer protective devices
shall be in accordance with MIL-I-1361.
220.127.116.11 Potential transformers. Potential transformers for metering
shall be in accordance with MIL-I-1361, shall have a Navy classification
accuracy NSS, shall be H.I. shock resistant, and shall have a standard burden
rating of not less than 100 V A.
3.6.8 Relays. Relays shall be provided and installed (see 3.6.14) as
specified in the ATDP and shall conform to the following:
(a) D.C. relays shall have arc suppression circuitry for the coil
provided as an integral part of the relay.
(b) 4PDT relays shall be 28 V d.c., 48 V d.c. 115 V 60 Hz, or
115 V 400 Hz in accordance with MIL-R-6106 and MS27400.
(c) 24PDT and 48PDT relays shall be in accordance with MIL-R-5757
and Drawing 803-4680146.
(d) 4PDT latching relays shall be in accordance with MIL-R-6106
(e) lPST and 3PST relays used in type VII switchboards shall be in
accordance with MIL-R-6106 and MS24140, MS24168, or MS27997.
3.6.9 Synchros. Internal unit connections and wire markings shall be in
accordance with requirement 2 of MIL-STD-1657.
18.104.22.168 Synchro capacitors. Synchro capacitors as specified in the ATDP
shall be connected across the stator leads of differential transmitters and
control transformers. Synchro capacitors shall be delta connected, and rated
at 600 V d.c. for 60 Hz synchros and 1,000 V d.c. for 400 Hz synchros. The
three capacitors used as a bank for one synchro shall be matched within 1
percent. Each capacitor shall have the values shown in MIL-HDBK-225 within
plus or minus 10 percent.
22.214.171.124 Synchro electrical zero and equipment mechanical zero. It is
essential that synchro components be correctly alined with respect to each other,
and to the device or parent equipment with which they are used. Electrical
zero is the reference point for alinement of all synchro components. Mechanical
zero or reference point for the device or parent equipment using synchro compo-
nents depends upon the particular application of the equipment involved.
Whenever a synchro component is used, either as a transmitter or receiver, the
synchro electrical zero and the equipment mechanical zero, unless otherwise
specified in the ATDP, shall be physically positioned to the same point. Synchros
shall be electrically zeroed by the methods specified in MIL-HDBK-225 prior to
delivery of equipment.
3.6.10 Wire terminal lugs. Except for contacts used with connectors,
pressure grip terminal lugs in accordance with figure titled "Type WTG terminals,
square tongue, one bolt hole" of MIL-T-16366 or MIL-T-7928 shall be used. In-
sulated barrel terminal lugs shall be used. Terminal lugs with projections or
"lips" shall be used in cases where necessary to prevent turning of terminal
lugs and shorting due to close clearances. Terminal lugs for connection of ship
wiring are not required to be provided by the manufacturer.