Safety Inspection And Tests After Repair And Maintenance; General Directives; Safety Components; Checking The Protective Earth Connection - Philips PM 5390 Service Manual

SAFETY
INSPECTION
AND
TESTS
AFTER
REPAIR
AND
MAINTENANCE
IN
THE PRIMARY
CIRCUIT
GENERAL
DIRECTIVES
—
Take
care that creepage distances
and clearances have not been reduced
—
Before
soldering, wires:
—
should be bent through the holes of solder
tags,
or
wrapped round
the tag
in
the
form
of an
open
U,
or,
wiring
ridigity shall
be maintained by
cable
clamps
or cable
lacing.
^
Replace
ail
insulating guards
and
-plates.
SAFETY COMPONENTS
Components
in
the
primary
circuit
may
only be renewed
by components
selected
by
Philips, see also
chapter
9.1
.
CHECKING THE
PROTECTIVE
EARTH CONNECTION
The
correct connection and condition
is
checked by
visual
control
and by measuring
the
resistance
between
the protective -lead
connection
at
the plug and the cabinet
/fra
me.
The
resistance
shall
not be
more
than 0.5
r2.
During
measurement
the
mains
cable should be
moved.
Resistance variations Indicate
a
defect.
CHECKING THE INSULATION RESISTANCE
Measure the
insulation resistance at
U =
500
Vdc
between
the
mains connections and
the protective
lead
connections. For
this
purpose
set
the
mains switch to
ON. The
insulation resistance
shall
not be
less
than 2 M^2.
Note;
2
is
a
minimum
requirement
at
40^ C
and
95
%
relative
humidity. Under normal
conditions the
insulation resistance
should be
much
higher (10 to
20 MO).