Du Pont SORVALL RC-5 Service Manual page 188

Son/all®
Centrifuges
Calibration
Procedures7.
Set
the
main circuit breaker to OFF,
then
remove
the clamp-on
ammeter.f.
Speed
Control
Low Speed
Potentiometer (R18) and High
SpeedPotentiometer
(R9)
SetThis
calibrates
the
speed
control circuit for accurate control
of
rotor
speed.1.
Install
an
SS-34
rotor,
then latch the chamber
door.2.
Connect
the
portable tachometer to
the SPEED indicator (-) minus terminal
andpotentiometer
R109
center
tap
located
behind the console
on
the RC-5. On the
RC-5B,
connect
the
portable tachometer to
the tachometer
jacks
on the front
panel.3.
Set the SPEED
control to
1000
rpm.4.
Place the
system
in the RUN
mode.5.
Adjust
potentiometer
R18
for
a
tachometer
indication of 1000
rpm.6.
Set the SPEED control to 20 000
rpm.7.
Adjust
potentiometer
R9 for
a
tachometer
indication of 20 000
rpm.
If full
counter¬clockwise
adjustment does not result in
20 000
rpm
Indication, adjust torque
trim¬mer
potentiometer
R204
until
20 000
rpm
is
indicated.3.
Speed Indicator
Ml 01
Tracking
Adjustment
Potentiometer(R109)This
procedure
adjusts
the full
range
of
speed
indication.1.
Install
an
SS-34
rotor and latch the chamber
door.2.
Place the
system
in the RUN
mode. Connect
the
portable tachometer to
the
SPEEDindicator
(-) minus
terminal and
potentiometer
R109
center tap on
the RC-5.
Onthe
RC-5B. connect
the
tachometer to the tachometer jacks on the front
panel.3.
Operate
alternately at
1000
rpm
and 20 000
rpm,
then
adjust
potentiometer
R109until
the error at both
speeds
is
minimized.h.
Overspeed Detector Potentiometer
(R73)This
procedure adjusts
the
overspeed detection circuitry
for RUN
mode
disable
at22
000
rpm
± 200
rpm.1.
Install an
SS-34
rotor and latch the chamber
door.2.
Adjust
potentiometer
R73
to disable the
RUN
mode when
the
motor speed
is
at22
000
rpm
±
200
rpm.7-5