Fluke 415B Instruction Manual page 45

41
5B
c.
Set the
HIGH
VOLTAGE
switch
to
ON. The
ripple
indication shall be less than 1.0
millivolt
peak-to-
peak and
less than 100 microvolts
RMS.
d.
Adjust
the line
voltage
from
103
to
127
volts
and
observe
the ripple indication. Ripple
shall
be
within the limits specified
in
step
c.
e.
Set the
first
OUTPUT VOLTAGE
dial to 2500, the
second
dial to
500
and
other dials to zero.
f.
Vary
the output of the
autotransformer between
103
and 127
volts
and observe
the ripple indication.
Ripple
shall be
within the
limits specified
in
step
c.
4-27.
OUTPUT VOLTAGE ACCURACY.
To
determine
the
accuracy
of
output at
each
OUTPUT VOLTAGE
switch setting,
perform
the
procedures
of
paragraphs
4-30
and 4-31, deleting
the
adjustments.
4-28.
OVERCURRENT
CHECK. To
check
the trip
point
of
the overcurrent
circuit,
perform
the
procedures
of
paragraph
4-33, deleting the
adjustments.
4-29.
CALIBRATION
4-30.
3000
Volt Adjustment
4-31. Before
making
calibration adjustments,
the unit
must
have been operated
at
normal
line
voltage for
at
least
one hour with an
output
of
3100
volts.
Proceed
as
follows:
a.
Set the output
of
the
autotransformer
to
115
volts
and
set the
controls
of
the
Model 415B
as follows:
POWER
POLARITY
HIGH
VOLTAGE
Output VOLTAGE
dials
ON
Negative
STDBY/RESET
First
dial
to
2500;
second
dial to 500;
others
to
zero
b.
Connect
the output
terminals
of
the
Model
80F-5
voltage divider
across
the input
terminals
of
the
Model
88 5A. Connect
the divider input
across
the
Model 415B
OUTPUT
connector.
c.
Set the
HIGH
VOLTAGE
switch
to
ON
and
adjust
the
Model 885A
to
measure
300
volts.
d.
Adjust
R26
on the
Amplifier
P/C Assembly
for a
null Indication on the
Model
885A.
This adjustment
is
accessible through the hole
in
the top cover.
Make
the
adjustment
to
better than
±100
millivolts
of
3000
volts (±10 millivolts on the
Model
885A).
CAUTION!
Use an
insulated screwdriver to adjust
R26.
With
negative
output
polarity,
the case of
this
resistor
is
83 volts
above
chassis
ground. With
positive
polarity output, the case
would
be
3083
volts
above
chassis
ground.
e.
If
the
potentiometer
is at
its
limit or the adjustment
can
not
be achieved, refer
to
paragraphs 4-46 and
4-48.
f.
Set the
POLARITY
switch
to
Positive
and observe
that
the output
is
within
the limits
of
step
d.
Do
not adjust!
4-32.
LINEARITY CHECK.
Proceed
as
follows:
a.
Set the first
OUTPUT VOLTAGE
dial to
the
2500
volt
position and
all
other dials
to
zero.
Connect
the
voltmeter-voltage divider combination across
the
OUTPUT
connector.
b.
Step
down
the first dial
and observe
that the volt-
meter
null
indication
is
within
the limits given
in
Figure 4-3.
Discontinue use
of
divider after 1500
volt step;
connect the
voltmeter
directly to
OUTPUT
connector.
c.
Repeat
the
measurement
of step b
for the second
and
third
decades.
DL.4.L
OUTPUT VOLTAGE NULL
READING
STEP TOLERANCE
500
VOLT
2500 250
millivolts
®
STEPS
2000 200
millivolts
®
1500 150 millivolts®
1000
1
.
0 volts
500
0. 5
volts
100
VOLT
400 400
millivolts
STEPS
200 200 millivolts
100 100 millivolts
1
n
VOLT
80
»n millivolts
STEPS
60
60 millivolts
40 50 millivolts
20 50 millivolts
10 50
millivolts
NOTE:
®
Tolerance applies
to 10:1
divider
output.
Figure 4-3.
LINEARITY
TEST: 500,100
AND
10
VOLT
STEPS
d.
Dial the 1-volt step
decade from zero
to the 9 volt
position.
Observe
that the output voltage increases
in
even
steps.
Output voltage
at
9-volt setting
should be
8.
95
to
9.
05
volts.
e.
Set
all
OUTPUT VOLTAGE
dials to
zero, then turn
the
vernier
control to
maximum
output.
The Model
885 indication
should be
between
1.
05
and
1.
35 volts.
f.
Check
the resolution
of
the vernier by
adjusting the
output to
1.
0
volt.
It
should be possible
to
adjust
the
vernier
to within ±5 millivolts
of
a
1.
0 volt null
on the
Model
88 5A.
4-33.
OVERLOAD
CURRENT.
To
check and adjust
the
overload current
circuit
proceed
as
follows:
a.
Set the controls
of
the
Model
41
5B
as follows:
4-4
POWER
POLARITY
ON
Negative
Rev.
1