540B
d.
e.
The
resulting
GALVANOMETER deflection indi-
cates
the amount of de
reversal
error
. T
he
per
-
cent
change
may
be
computed
by
multip
lying the
deflection
sens
i
tivity
determined
in
step
a by the
amount
of de
reversal
error.
Set
the
GALV
sw
i
tch
to OPEN. Set the POLARITY
switch to
its
normal,
up, position.
2-
1
7.
VOLTA G E M EA S
UREM
ENT A N D
CALI BRAT
IO
N
2- 18. MEASURING AN
UNKOWN
AC
VO
LTAGE
2-19. Complete the Battery Check of
Figure
2-4. With
the
RANGE
switch in the 1000 volt position
an
d the
MODE
s
witch
se
t to
OFF,
connect
the
ac
v
olt
a
ge
to
the AC
IN
P UT
te
r
minals
and
the
de
so
u
rce
to
the
DC
INPUT
ter
mina
l
s.
Use the
procedure
of F
igure
2- 6.
2-2
0.
CALIBRATING AN
AC
V
OLT
AGE SOURC E
2-21. Complete the Battery Check
of
Figure
2-
4. With
the
RANGE
switch in the 1000 v
olt
pos
iti
on
and the
MO
DE
switch
set
to OFF, connect the ac
sourc
e to
th
e
AC
IN-
PUT
terminals
and
the
de
source
to
the
DC
INP UT
terminals.
Follow the
procedure
of Figure
2-
7,
for
the
calibration
of an
ac
voltage
source
.
If
a
test
report
from
a
standards
laborator y
is
used, adjust the de source voltage
in
step
a
to
equal 100
times
the
rms
value of
100
+ a
0
the
ac
voltage to be
calibrated.
Where
a
0
is
the
ac
to de
percent
difference
from
the
test
report.
2
-2
2.
CURRE
N T M EAS UREMENT
AND
CALIBRATION
2-
23. GENE
RA
L
2-2
4. A
current
shunt will not be
requ
ir
ed
if the c
ur
-
rent
to be
measured
or
calibrated
is 2. 5 to 5
milli-
amperes. The thermocouple
of
the Model
A5
4
is
capabl
e
of handling
this
amount of
current.
2-25.
Current
shunts
rated
up to 30 milliamper es
are
plugged
directly
into the
SHUNT
terminals
of the Model
A54.
Current shunts from
50
milliamperes to 5 amperes
are
also
plugged
directly
into the
SHUNT
terminals
of
the Model A 54.
However,
a
special
retaining
screw
(located on the
rear
panel
of the Model
A5
4)
is
used
to
secure
these
larger
current
shunts to the front
pane
l of
the
Model A54. The Fluke Model
A40A
Current
Shunts,
10 and 20
ampere
are
connected to
the
Model A54 with
a
special
cable
(fluke
part
number 6002- 212860,
illus
-
trated
in
Figure
6-4).
2-26.
To
eliminate
the
process
of
int
e
rchanging
the
ac
and de leads to a
current
shunt, the Fluke Mod
el
A45
C
ur
r
ent
Transfer
Switch
may
be
use
d.
Pr
o
per
ca
bl
es
and
con
n
ect
i
ons
to
current
shunts
in
conju
nctio
n
with
the
Models A54 and A45
are
illus
tr
at
ed
in F i
gure
2-8
.
2-
8
2-27.
Two
precautions
in
regard
to
lead
length
and
effects
of
the
Model A45 upon a voltage
source
should
be
considered.
a.
To
minimize
errors
from
induced
voltages
when
connecting a
current
shunt
or
. Mod
el
A45
to
a
cir-
cuit
under
test,
use
a coaxial cable 30
centimeters
or
less
in length.
b. Due
to the shorting type
transfer
switch
of
the Model
A45, a
current
limiting
resistor
should be
placed
in
series
with a voltage
source
used
as
a
current
source.
If
the
current
limiting
resistor
is
not
used
there
is
a
possibility
that
the
voltage
source
could
be damaged.
2-
28. MEASURING AN UNKNOWN AC
CURRENT
2-
2
9.
Complete the Battery Check of
Figure
2-4. With
a common
commercial
ammeter,
measure
the unknown
current
in
order
to
select
the
proper
Model
A40
or
Model
A40A
Current
Shunt.
If
determination
of
de-
flection sensitivity
is
desired,
refer
to
Figure
2- 5 and
substitute
step
a with
the
following:
MODE
switch
to
OFF,
RANG
E switch to
SHUNT,
GALV
switch to
OPEN,
and
POWER
switch
to
ON.
Follow
the
procedure
of
Figure
2-9,
for
measurement of
an
unknown
ac
current.
The
PERCENT
INPUT
meter
of
the
Model
540B
does
not function
in
the
current
mode
of operation.
CAUTION
Protectio
n
from
overload
is
not
provided
for
the
current
shunts
or
the thermocouple
of the Model
A54
when
in
the
SHUNT
position
of the
RANGE
switch (current mode
of
oper-
ation).
2-
30.
CALIBRATING AN AC
CURRENT
SOURCE
2-31. Complete
the
Battery Check
of
Figure 2-4.
Refer
to
paragraph
2-
23
,
for
proper
shunt
selection
and
con-
nections.
The
current
shunt
selected
should
be
of
the
lowest value possible without exceeding
the
rated
value.
Observe
the
note and caution of
paragraph
2-29.
Use
the
procedure
of
Figure
2-10,
for
calibrating
an
ac
current
source.
If
an
A40
or
A40A
test
report
is
used, adjust
the
de
source
un
til
the
de
current
equals
100
times
the
rms
value of the
ac
cur
-
100
+ a
0
rent
desired. Where
ao
is
the
ac
to
de
per
-
cent
difference
fr
om
the
test
report.
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