Burden
Meter
Accuracy
Scale Accuracy
Electronic Wattmeter
Chapter 1
No
more than 1.5kV peak should
be
applied between the upper
pair of
terminals and either ground or the lower terminals. The
latter must not exceed 400V peak to ground.
Current ranges
Nominal 0.05, 0.1, 0.2, 0.5,
1,
2,
5 and 1
OA.
Overload Indication
Input peaks of voltage or current
in
excess of 1.5x the nominal
range can cause overload which is clearly indicated by the
appropriate
voltage or current overload lamp.
Overload Protection
All current circuits
are
protected by a 1
OA
slow-blow 1/4" x 1 1/4"
fuse mounted
on
the rear panel. The circuit is designed
to
withstand the transient associated with normal rupturing of this
fuse
on
all
current ranges. The voltage circuit will withstand the
nominal 250V a.c supply indefinitely
on
any range.
Frequency range
DC
to
20kHz.
All voltage ranges; 5kQ/Volt
All
current ranges; less than 60mQ
3 1 /4" mirror scale graduated 0 to 1.0
in
50
divisions
Reading given by:
Watts=
(meter deflection) x (Voltage range) x (Current range)
Pushbutton to give x2
scale expansion and pushbutton meter
reversal.
Many factors control the final indication
on
any wattmeter. They
include voltage, current and power ranges, power factor,
temperature and frequency.
The possible permutations of these are
so
numerous that it
is
impracticable to specify or to test instruments under all likely
operating conditions. The figures below should
be
interpreted
in
the light of these comments.
All figures are at 50Hz, unity power factor, 25oc.
Typically better than 1.5% of fsd measured
on
1
OOV
and 0.5A
range at
20,
40,
60,
80
and 100% of fsd with a 200 ohm load
(guaranteed better than 2.5% of fsd).
Also typically better than 2% of fsd for all combinations of 0.25A,
0.5V,
0.
75A and 1 A with 25V, 50V, 75V and 1
OOV
applied to the
1 A and 1
OOV
ranges.
7
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