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Your Guide to Correct
METER INSTALLATION
This manual has been designed to help you install GE watthour
meters quickly and easily. It provides a handy reference
covering the most common types of both single-phase and
polyphase installations.
To quickly find the particular information you need, just refer to
the side tabs which separate the wiring diagrams into seven
circuit arrangements. Two colors have been used to distinguish
the external wiring from the internal wiring, making the
diagrams easier for you to read. The internal wiring is shown in
black and the external wiring in red.
See page II for information on meter load-carrying capability and
associated wiring and mounting.
WARNING
Any work on or near energized meters, meter sockets, or
other metering equipment may present a danger of electric
shock.
All work on these products should be performed only by
qualified industrial electricians and metering specialists in
accordance with local utility safety practices and the
procedures specified in the Handbook for Electricity
Metering (9th Edition), chapter 13 (available from the Edison
Electric Institute, 1111 19th Street NW, Washington, DC
20036).
The wiring diagrams and other data contained within this
book are intended to be an aid to qualified metering
personnel. They are not intended to replace the extensive
training necessary to install or remove meters from service.
WHERE TO FIND IT
1
Single-phase, 2-wire circuits
Single-phase, 3-wire circuits
Network, 3-wire and 3-phase, 3-wire circuits
Three-phase, 3-wire circuits
Three-phase, wye, 4-wire circuits
Three-phase, delta, 4-wire circuits
Miscellaneous circuits
METER CLASSES
Modem-type meters in socket and bottom-connected construction are
designated as Class 100, Class 200 or Class 10 or 20. Class 100
meters (15-ampere test rating) are rated 15 amperes but are capable
of carrying, and measuring accurately, loads up to 100 amperes when
suitably wired and mounted. Class 200 meters (30-ampere test rating)
similarly have extended load capacity up to 200 amperes when
suitably wired and mounted. Class 10 or 20 (transformer rated) meters
are used with current transformers and require special sockets with
circuit-closing devices.
For complete details on single-phase and polyphase meters, current
and voltage transformers, and all socket mountings. contact the GE
Meter Business Department, Somersworth, NH 03878.
METER MULTIPLIERS
Transformer Factor (‘TF”)—The proper multiplier for Transformer rated
meters with secondary reading registers must always include the ‘TF,”
i.e.. CT ratio, or CT ratio x VT ratio when VT’s are used.
NOTE: Primary-reading registers have transformer ratings on
nameplate and multipliers of 1, 10, 100, or 1000.
II
METERING SYMBOLS
Kh =
Watthour constant (or test constant) is the
watthours per revolution of the meter disk
PKh = Primary watthour constant (watthours per revolution
of the disk, primary rating) = Test constant X TF
Rr
= Register ratio (turns of register worm gear for one
revolution of fastest dial {right hand} pointer)
Rs
= Shaft gear reduction (ratio between rotor shaft and
engaging gear)
NOTE: Rs formerly designated as Gr
Rg
= Gear ratio (number of revolutions of the disk for one
revolution of fastest dial {right hand} pointer)
TF
= Transformer factor = CTR x VTR
Kr
= Register multiplier (or dial constant). Multiply dial
reading by Kr for kilowatt-hours
METERING FORMULAE
10,000 X Kr
Rr X Rs
Kh
(watthour constant) =
PKh
Kh X TF = Kh X CTR X VTR
Kr
(Dial Constant) =
Rg
(Gear ratio) = Rr X Rs
Rg
(for GE Meters, except V-60, DS-50 and DS-60 family
meters) = Rr X 100
Rg
(for V-60, DS-50 and DS-60 family meters) = Rr X 50
Rr
(register ratio) =
Watts =
Kh X Rr X Rh X TF
10,000
10,000 X Kr
TF X Kh X Rs
3,600 X disk rev X PKh
T (time in seconds for disk rev)
WATTHOUR-METER CONSTANTS AND
REGISTER DATA
The watthours per revolution of the meter disk is called the
watthour constant (Kh). When watthour meters are used with
instrument transformers (transformer-rated), the secondary
watthours per revolution of the disk is the test constant (Kh);
the product of the test constant, the current-transformer (CT)
ratio, and the voltage-transformer (VT) ratio is the primary
meter constant (PKh).
The gear ratio (Rg) is the gear-train ratio between the rotor
shaft and the fastest pointer shaft. It is the register-ratio (Rr)
multiplied by the gear reduction (Rs) between the rotor shaft
and the shaft of the worm gear or the gear meshing with it.
The gear reduction at the shaft (Rs) is 100 for all GE meters
except the V-60, DS-50 and DS-60 family meters. In the V60, DS-50 and DS-60 meters Rs is 50.
The register multiplier (Kr) is the constant by which the dial
reading must be multiplied to obtain kilowatt-hours. For most
self-contained meters, this is 1.
There is a definite relation between these quantities. The
watthours measured over a given period are, of course, PKh
X revolutions of the disk. Therefore, the kilowatt-hours =
PKh X rev of disk
1,000
The kilowatt-hours also equal revolutions of the fastest (first)
pointer X 10 X Kr
PKh X rev of disk
= new first pointer X 10 X Kr
1,000
WATTHOUR-METER CONSTANTS AND
REGISTER DATA (cont)
Gear ratio Rg =
rev of disk
=
Rev of 1st pointer
=
Register Ratio Rr =
Rg
Rs
10 X Kr X 1,000
PKh
10,000 Kr
PKh
=
10,000Kr
Rs X PKh
For all GE meters except V-60, DS-50 and DS-60 series
meters:
R=
100Kr
PKh
For V-60, DS-50 and DS-60 series meters:
R=
200Kr
PKh
TEST FORMULAE
Portable Watthour Meter Standard
kh X
r (with no corrections for portable standard)
X 100
Kh X R
A=
A=
kh X r
X 100 X Astd (over-all meter accuracy)
Kh X R
where:
A = percent accuracy of meter and Astd = percent accuracy of standard
Kh = watthour constant of meter under test
r = revolutions of meter under test
Kh = watthour constant of standard
R = revolutions of portable standard
Ri =
kh X r
Kh
Where:
Ri = calculated revolutions of standard
A=
Ri
R
X 100 percent accuracy
TEST FORMULAE (cont)
Rules for Determining Calibrating Constants
When testing polyphase watthour meters with a single-phase portable
watthour meter standard, the value of one revolution of the disk of the meter
under test varies with the connections. Thus, a test constant, called a
calibration constant (Calib C), is used which relates to the watthour meter
constant kh as follows:
1.
Testing Two-stator Meters
3-wire 3 phase / 3 or 4-wire 2-phase
Individual circuits
Circuits in series
4-wire Y 3 phase (2 ½ stator)
Individual circuits:
Single Coil
Double Coil
Three Circuits in series
4-wire Delta (), 3 Phase
Individual circuits:
2-wire Coil
3-wire coil windings
Separately
In Series
Three Circuits in series
2.
Testing Three-stator Meter
4 wire Y 3 phase
Individual Stators
Two stators in series
Three stators in series
4-wire Delta (), 3 Phase
Individual stators
Two 120-V stators in series
Calib C = kh
Calib C = ½ kh
Calib C = kh
Calib C = ½ kh
Calib C = ¼ kh
Calib C = kh
Calib C = 2xkh
Calib C = kh
Calib C = ½ kh
Calib C = kh
Calib C = ½ X kh
Calib C = 1 3 X kh
Calib C = kh
Calib C = ½ X kh
TEST FORMULAE (cont)
Rules for Determining Calibrating Constants
3.
Totalizing
3-wire 3 phase / 2 wire single-phase
Individual circuits
Two 240-V stators in series
3-wire 3 phase / 3-wire single-phase
Individual circuits:
Individual Stators
Two stators in series
Three stators in series
Calib C = kh
Calib C = ½ X kh
Calib C = kh
Calib C = ½ kh
Calib C = 1 3 kh
Instrument Test Method
A=
kh X r X 3,600 X 11 percent
wXt
Where
A=
Percent accuracy
kh = watthour meter constant in watthours per revolution of the disk
r = revolutions of meter under test
3600 = number of seconds in an hour
w = watts load (with corrections for instrument inaccuracy). Also,
w = voltage X amperes X number of stators, when tested on singlephase. Also,
w =
t
=
voltage X amperes X circuit constant (ie: 3 for 3-wire, 3phase, when tested on polyphase
time of test (seconds)
Determination of Watts Load
The watthours measured by watthour meter are:
PKh X rev of disk =
or as usually written
watts X t
3600