Except for ammeters and voltmeters or unless otherwise specified or
approved, the nominal or full-load values shall appear at the approximate
mid-point, or the 12 o'clock position, of the scales.] [Electrical
instrumentation devices shall be compatible as a system, sealed, dust and
water tight, utilize modular components with metal housings and digital
instrumentation. Date display shall utilize LED or back-lit LCD. Numeral
height shall be [13 mm 1/2 inch] [_____].]
2.7.7.1
Wattmeters shall comply with ANSI C12.1 and ANSI C12.10 except for mounting
and shall be the three-phase, [four-wire type with three current coils and
three potential coils] [three-wire type with two current coils and two
potential coils].
2.7.7.2
Varmeters
Varmeters shall be the center-zero type and provided with integral or
separate phase-shifting transformers or compensators. Varmeter shall be
the three-phase, [four-wire type with three current coils and three
potential coils] [three-wire type with two current coils and two potential
coils]. Varmeters shall have dial markings and be so wired that incoming
VAR readings shall be to the left of zero and outgoing VAR readings shall
be to the right of zero. Dials shall be so labeled.
2.7.7.3
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NOTE: Normally, 3/4 of full-scale should be
specified. Mid-scale should be specified when
current transformers will be operating at currents
exceeding their ratings.
**************************************************************************
Ammeters shall be calibrated to indicate full-load current when supplied
with a current of 5 amperes. Full-load current shall be indicated by the
pointer at approximately [mid-scale] [75 percent of the full-scale range].
Ammeter switches shall be of the short-circuiting type provided with an off
position, wired for indication of current in each phase, and shall be
provided for each ammeter shown or specified.
2.7.7.4
Voltmeters and Voltmeter Switches
Voltmeters shall be provided with expanded scales and calibrated to
indicate the nominal [phase-to-phase] [and] [phase-to-neutral] voltages at
approximately mid-scale. A voltmeter switch shall be provided with an off
position, wired for indication of applicable voltages, and shall be
provided for each voltmeter shown or specified.
2.7.7.5
Demand Registers
Demand registers shall comply with ANSI C12.4.
2.7.8
Electrical Recording Instruments
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NOTE: Recording instruments should be provided when
specifically requested by the Using Agency.
Coordinate various types and characteristics with
SECTION 16311A
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