Du Pont SORVALL RC-5 Service Manual page 28

Sorvall®
Centrifuges
Theory
of
OperationSection
3THEORY
OF
OPERATION3-1.
GeneralThis
section provides
the
Information necessary
to understand
the
electronic,
drive
andrefrigeration
circuits of the
RC-5
and
RC-5B
Centrifuges.3-2.
RC-5
Theory
of Operation (figures
3-1
through3-10)a.
Operational
ModesThe
RC-5
centrifuge operates in two main mode
conditions:
HOLD
and
RUN.In
the HOLD
mode,
the
following
conditions
occur:•
Main
power
is
present
in the
centrifuge
and the rotor is at
a
dead
stop or
slowingdown
from
a previous
RUN
cycle.•
The HOLD set
pointer controls
the
refrigeration system
to maintain the
preset
tem¬perature.•
The door Interlock circuit allows the
door
to be
opened.In
the RUN
mode,
the
following
conditions
occur:•
The
rotor rotates at a preset
speed.•
The RUN set
pointer controls
the
refrigeration system to maintain
the
preset
tem¬perature.•
The door interlock circuit
prevents
the
centrifuge
chamber door from
opening.b.
HOLD
Mode1.
Power,
Interlocks and Power
IndicationWhen
CB301,
30 A
main circuit breaker is closed,
115
Vac is applied through
thefront
panel
Interlock switch S305, then to
power
transformer
T201.230
Vac operating volts for
the
compressor
and rotor center
drive
motors comes
di¬rectly;
from the main 230 Vac
input power
line. The
primary
winding of
transformerT201
is
tapped
to
provide
27 Vac reference voltage to 230
Vac,
for
operating
thebrush
warning Indicator
circuit.3-1