panels and adjacent to the relays. AC relays shall be suitable for use
on 60-Hz circuits and for operation with the instrument transformer
ratings and connections shown. Relay current coils shall be able to
withstand 35 times normal current for 1/2 second, and relay voltage
coils shall be able to withstand 110 percent rated voltage continuously
without damage. Time delay features shall not depend upon oil dashpots
or other devices which are appreciably affected by temperature. Each
relay shall be provided with 1 or more operation indicators and/or
indicating Contractor switches with targets and external target reset
devices, and the circuits shall be arranged for positive target
operation. Seal-in Contractor and suitable loading resistors shall be
provided where required. Separate relay operating function, such as
instantaneous trip attachments and different zones for distance relays,
shall have separate targets and contacts.
c. Relay contacts shall be silver-to-silver, electrically independent,
chatterproof and non-bouncing, and suitable for use on 125-volt
ungrounded DC circuits unless otherwise specified or shown. Where more
than one electrically-independent relay contact is required, as
indicated , and it is not feasible to provide more than 1 such contact,
or if 2 contacts are available but are not electrically independent,
auxiliary relays shall be furnished to provide the required additional
contacts.
2.5.10.2
AC Voltage Relays
Voltage relays other than ground detector relays shall be induction-disc
inverse-time type with adjustable time and voltage settings and with
semiflush mounting, drawout case type [_____]. Ground detector relays
shall be induction-disc inverse-time overvoltage type rated 199 volts AC
with low pickup, semiflush mounting in drawout case with circuit closing
contacts suitable for 125-volt DC ungrounded circuits. They shall be from
the same manufacturer as the AC voltage relays, type [_____].
2.5.10.3
Auxiliary relays
Auxiliary relays for bus transfer control shall be semiflush back-connected
type for front-of-panel mounting. The semiflush cases shall be black and
shall match in appearance other relay cases on the switchgear. Auxiliary
relays for interior mounting shall be provided with covers. Relay coils
and contacts shall be suitable for continuous operation at 125 volts DC,
shall be furnished with resistors where required, and shall be of a type to
require a minimum continuous current. The auxiliary relays shall be
high-speed, multi-contact, self-reset type, from the same manufacturer as
the AC voltage relays, type [_____].
2.5.11
Control and Instrument Switches
2.5.11.1
General
All control switches shall be of the rotary switchboard type with handles
on the front and the operating contact mechanisms on the rear of the
panels, type [_____]. Each switch shall be provided with ample contact
stages to perform the functions of the control system. Contacts shall be
self-aligning and shall operate with a wiping action. A positive means of
maintaining high pressure on closed contacts shall be provided.
Compression springs or pivotal joints shall not carry current. The covers
or plates on the switches shall be readily removable for inspection of
contacts. All control switches shall be suitable for operation on 600-volt
SECTION 16404A
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