Input Overload Protection; Common - Fluke 8021B Instruction Manual

802 IB
Table 2-1. Controls, Indicators
and
Connectors
(coot)
K59
NAME
FUNCTION
10 (cont)
When
used
with the
ft
function, the
"in"
position
enables the audible continuity
tone.
Power Switch
A
slide
switch used
to-
turn
the
instrument
off
and
on.
2-13. input
Overload
Protection
CAUTION
Exceeding the
maximum
input
overload
limits
can damage
your instrument.
A
transient
overload protection
circuit
is
designed
into
the 8021
B
to protect
it
against short duration high
energy
puises.
The components
used
limit
the
protection to
approximately
five
puises per
second
for 6
KV,
10
microsecond
pulses,
and about
0.8
watts average for lower amplitude puises. Fast repetition
rate
puises
such as those from
a
TV
set
can
damage
the protection
components; RJ1
-
RJ4, R1 and R2.
If
any
of
these
components
require
replacement,
use only Fluke parts to
ensure product
safety.
R2
is
a fusible
resistor.
Use exact replacement
to
ensure
safety.
2-14.
Each measurement
function
and
its
associated ranges are equipped with input
overload protection.
The
overload
limits for
each
function
and
range are given
in
Table
2
-
2
.
2-15. Input
Connections
to
COMMON
WARNING
TO AVOID ELECTRICAL
SHOCK AND
/OR
INSTRUMENT
DAMAGE DO
NOT
CONNECT THE
COMMON
INPUT TERMINAL
TO ANY SOURCE OF
MORE THAN
500
VOLTS
DC OR RMS AC ABOVE
EARTH GROUND.
2-
1
6.
The
802
1
B
may
be operated with
the
COM MON
input terminal
at a
potential of
up
to
500V
dc or
500V rms
ac
above earth ground.
If
this
limit
is
exceeded,
instrument
damage may
occur. This,
in turn,
may
result
in
a safety
hazard for the operator.
2-17.
Fuse Check
2-18. The
current
(mA)
function contains
two
fuses.
Check them
as follows;
1.
Complete the
set
up
steps for the
RESISTANCE
(fl)
function and select the 2
kil range.
2.
Touch
the red
test
probe
to
the
m A
input jack so
that
the V-ft input
and
mA
input are
connected
together.
3. if
the
display reads
approximately
.100
kll,
both fuses
are good.
2-6