Du Pont SORVALL RC-5 Service Manual page 197

Calibration Procedures
Son/all®
CentrifugesTable
7-3. Potentiometer Adjustment
forP.C.
Board,
PN
50059
(continued)*R43
Temperature Control Blue Pointer (run).
With
rotor
in
position,operate
centrifuge at
approximately
1000
rpm.
Adjust to
turnCompressor
Off
when Temperature Indicating
Needle
meetsRun
Temperature Set
Point.*R58
Temperature Control Overtemperature Detector. Adjust to
cutpower
to Centrifuge Drive when Temperature Indicating
Needlereaches
a point
3°C
higher than Red (hold) Pointer
Setting.R73
Overspeed
Detector. Adjust
to
cut power
to Centrifuge Drive
whenrpm
exceeds
21
000
rpm.R84
Adjust 1.25 Second Pulse for Refrigeration
System.NOTEDo
not
adjust.
Adjustment made in
factory.*
When
adjusting potentiometers R40, R41. R42, P43. and R58. disconnect one
com¬pressor
lead from
relay
K201
to
prevent compressor
from
cycling on
and off.
Holdcycle
has
a
two minute
time delay after each
15
second cycle.
This time
delay
maybe
avoided
when callibrating
R42
by
placing one probe
of VOM
meter on
collectorlead
of
Q15 and other
probe
on
TP-1.Meter
will
read
5
Vdc
when compressor is in off cycle and
will
read
0 volts
when
com¬pressor
is
in run cycle. Temperature calibrating test set
may
also be used on
adjust¬ments
R42, R43.
and R58
using
variable
setting.7-14