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AB-10*-11*-13* -14 -15*-16 -18
DB-1 0;-12; -1 3:-14,-15:-16 , -18,
AMMETERS AND VOLTMETERS
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INTRODUCTION
These
instructions cover the installation
General Electric Types AB and Types DB a-c and
d-e ammeters and voltmeters. These instruments are
long-scale, rectangular-pattern, switchboard types de
signed for flush mounting. The instruments, as sup
plied, are intended for use on the circuit specified by
the customer.
There is a nameplate located on the back of each
instrument. This nameplate gives the serial number
and such information on the current or voltage rating,
frequency rating, transformer ratio, full-scale value,
and lead resistance as is applicable to the instrument.
On voltmeters, the nameplate also indicates whether
the resistor is internal or external.
Ammeters and voltmeters supplied with transfor
mers will have their scales calibrated in primary am
peres or primary volts respectively, unless otherwise
specified.
A-C AMMETERS
When the circuit exceeds 20 amperes, a current
transformer of the ratio indicated on the nameplate
must be used. When the circuit exceeds 650 volts a
current transformer must be used for purposes of in-
''' Discontinued type; no longer available
TYPE
!
Voltmeters
150-volt rating}
Ammeters
These instructions do not purport to cover all details or variations in equipment nor to r:: r ovide for every possible
contingency to be met in connection with installation, operation or maintenance. Sho:�fd further information be desired
or should particular problems arise which are not covered sufficiently for the purchaser's purposes, the matter should
be referred to the Genera/ Electric Company.
,
,
'
I
Effective
Impedance
Resistance
I
in Ohms
in Ohms
120-volt, 60-cycla Potential Circuit
)
3020
2960
5-ampere, 60-cycle Current Circuit
I
0.086
0.05
TYPES
'
'
'
AND
sulation. The current transformer must have a fre
quency rating which corresponds to that indicated on
of the
the instrument nameplate.
A-C
VOLTMETERS
When the circuit exceeds 750 volts, a potential
transformer of the ratio indicated on the instrument
nameplate must be used. The transformer must have
a frequency rating which corresponds to that on the
instrument nameplate.
An external Form-3 resistor must be used when so
indicated on the instrument nameplate. The table
below gives the number of tubes in the resistor sup
plied with instruments
When an externar resistor is used, it must bear the
same serial number as that of the instrument. The
Description
Sing/e.range
Single-range
Sing/e.range
Sing/e.range
Sing/e.range
Double·range
Double· range
BURDEN
DATA
I
I
Inductance
I
Volt-amperf!'s
in Henrie•
'r
I
I
I
4]6
.52
I
i
0.000187
2.15
AND
-1 9 *
,
AND
-19 *
of
various
voltage ratings.
EXTERNAL
RESISTORS
Volts
External Resistor
150
None
175, 300
One J.tube
350
One
500
One
600, 750
One 4·tube
75/150
None
150/300
One
I
Vors
Watts
I
I
I
4.67
0.94
I
1
1.25
78
1
· -·
1
t
or
·
ube
2
·
t
u
be
4
t
.
u
be or
2
ub
·
t
e
1.tube
I
Power Foetor
I
I
I
0.98
i
0.58
3
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