Du Pont SORVALL RC-5 Service Manual page 85

Sorvall® CentrifugesDrive
System
CircuitSection
4DRIVE
SYSTEM
CIRCUIT4-1.
GeneralThis
section
covers
the
procedures
necessary
to understand and troubleshoot the
cir¬cuits
of the drive
system.
It describes the relationship between the drive
motor,
thesaturable
reactor
and
the
associated control
systems
that create different modes
ofoperation.Troubleshooting
charts are included to
support
the text and aid maintenance
personnelin
isolating a
problem to a specific function or
area.4-2.
Drive
Motor
CircuitWhen
the
centrifuge is
operating
in the RUN
mode,
230 Vac
operating power
for
thedrive
motor is
supplied from the main
power source
through contacts
4-5
of
relay
K205to
the
ac winding of
the
saturable
reactor.
In the RUN
mode,
the drive
motor
enablecircuit
(paragraph
4-3)
is activated when
relays
K202 and
K205
are energized.
Whenthe
start switch is
depressed, latching relays K202,
K203
and
K205
are energized
by115
Vac.
and
relay
K202
applies
230
Vac potential to
the drive
motor
field
windings
tooperate
the
motor.
When
relay
K205
is
energized,
115
Vac
passes
across contacts
8-2and
is
applied to
the
speed control circuit which modulates the
dc saturating bias
volt¬age
on
the
control winding of the
saturable reactor to control the drive motor
speed.230
V
acFROMCB-301MOTOR
RELAYK202230
VacRETURNFROM
SPEEDCONTROL7/79RCS/30Figure
4-1. Drive
Motor Circuit,
SimplifiedSchematic
Diagram4-1