Sorvall RT/T6000D - Page 110

SORVALL9
Centrifuges
System
Descriptions:
Electrical
Figure
6-7.
Zero
Speed
Detection
Circuit
6-10.
Door
Interlock
Circuit
(refer
to
figure
6-8)
Two door
latches
ensure operator safety
by
keeping
the
door
closed
and latched while
a
rotor
is
spinning.
The latch
mechanism
is position-sensitive and
will
not
latch
unless
the
door
is
closed.
Microswitches
SW1A
(door)
and
SW4
(solenoid)
sense
when
the
door is
latched,
and
a
solenoid-operated lever
prevents
the
mechanism
from unlatching while
the
rotor
is
spinning.
A
zero-speed
signal
energizes
the solenoid
LI
when
the
rotor
stops
spinning.
This
allow
the
operator
to rotate
the
door release
knob
clockwise,
which
in
turn
activates
the
mechanism
to
unlatch
the
door.
At the
start
of
a
normal
run,
the
door
is
closed,
the
timer
is
set
to
a
position
other that
OFF,
and
the
door release
knob is
rotated
counterclockwise
to
latch the
door.
This
sequence
of
steps,
regardless
of
the
order
of
execution,
will de-
energize
the
solenoid.
The
de-energized
solenoid
prevents
the
operator
from
rotating
the
door release
knob
clockwise and unlatching
the
door
while the
rotor
is
spinning.
There
is
a
mechanical
override
of the solenoid lever
so
that the
door release
knob
can be
operated
in
an
electrical
failure. See
figure
3-3,
Location
Of
Mechanical
Relay Override.
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||^|g|||i||lli^^
ever
be
used
for
any
other
purpose.
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iitt^liwww^^
:
.off^^'^^ilnittBe^wI^
wait
until
the
rotor
stops
before
using
the
mechanical
.:.
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:'...
.:-'.:
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^:
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,.
'
^^i,^^',,^.^
:::
'^.^l^
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^
,.•
^•^^iiyS::^^'^^''--''''1"'"''1'-''^''''
If
the timer and
speed
control
knobs
are
turned
ON
while the
door
is
open
or
closed and
not latched,
the
interlock
opto-isolator
is turned OFF,
thereby preventing
power
control
signals
from
PWM
circuits from
getting
through to
the
SCR
motor
control
circuit.
In this
state,
no
voltage
passes
through
the emitter
diode of the
opto-isolator, so
it
is
turned off.