Panasonic NN-8508 - Page 10

NN-8508, NN-8558
NN-8808, NN-8858
NN-8808P
DESCRIPTION OF OPERATING SEQUENCE
ON, OFF TIME ON
POWER RELAY B
ON (SEC) OFF (SEC)
1. Variable power cooking control
The
coil
of
power
relay
B
(RY
B)
is
energized
intermittently
by
the
digital
programmer
circuit,
when
the
oven
is
set
at
any
power
selec-
tion
except
for
High
power
position.
The
digital
programmer
circuit
controls
the
ON-OFF
time
of
power
relay
B
contacts
in
order
to
vary
the
output
power
of
the
microwave
oven
from
“Warm”
to
“High”
power.
One
complete
ON
and
OFF
cycle
of
power
relay
B
is
22
seconds.
The
relation
between
indications
on
the
control
panel
and
the
output
of
the
microwave
oven
is
as
shown
in
Fig.
4.
NOTE:
The
ON/OFF
time
ratio
does
not correspond
with
the
percen-
©
tage
of
microwave
power
since
approximately
1.5
seconds
are
required
for
heating
of
magnetron
filament.
2. Cyclic defrost
When Defrost power and defrosting time is siesta and Start pad is
tapped:
(A) The digital programmer circuit (DPC) divides the total defrosting time
into 8 cycles of alternating ON-OFF intervals of defrosting power and
standing periods. (See Fig. 5)
(B) During each defrosting period, power relay B is energized for 9
seconds and de-energized for 13 seconds by DPC. (See Fig. 6)
(C) During standing periods, power relay B is always open resulting in no
microwave power.
Approx Please refer to description
120W of cyclic defrost.
NOTE: Defrost time selected is converted into seconds by the DPC but
display will show selected time in minutes and seconds as prog-
rammed.
The
total
number
of
seconds
is
divided
into
8
time
TOTAL
DEFROSTING
TIME
periods.
The
remainder
(seconds
not
equally
divisible
by
8)
are
i)
18
1a
vs
added
to
the
last
standing
time
period.
i
i
Example
:
if
defrosting
time
is
selected
for
5
minutes,
each
operating
period
will
be
as
follows
:
(See Fig.
7)
5
minutes
=
300
seconds
300/8
=
37
and
remainder
is
4
seconds.
The
4
seconds
is
added
to
the
last
time
period.
NOTE:
When
defrosting
time
is
selected
for not
more
than
7
seconds,
the
power
relay
B
will
not
be
energized
at
all.
OUTPUT POWER
INDICATION | AGAINST
HIGH POWER
mete
ao
Fig. 5
ONE DEFROSTING PERIOO(T/8)
aT
Fig. 6
S5MIN_(300SEC)
tsT 2ND 2ND LAST
STANDING( 37S) ,DEFROSTING(373) STANDING(373) STANDING( 443)
Fig. 7