Sorvall RT/T6000D - Page 124

SORVALL®
Centrifuges
System
Descriptions:
Electrical
Figure
6-19.
Closed-Loop
Speed
Control Circuit
If
the
run
is terminated
by
setting
the
speed
control
or
timer switch
OFF
(or
If
the
set
run
time
runs
out)
and the
brake
switch
Is In
the
ON
position,
the
deceleration
occurs
in
the
brake
mode.
If
a
lower
rotor
speed
is
selected
by
the
speed
control knob (but
the
run
is not
terminated),
the
rotor
will
coast
downward
to
the
new
set
speed
without
the
use
of
the
brake, even
if
the
brake switch Is
ON.
6-23.
Brake
Circuit
(refer to figure
6-21)
The
brake
circuit
Is
activated
by
the
loss
of
the
RUN
signal
when
a
time-out
occurs, a
fault
condition
exists, or
the
speed
control
or
timer
control
is
turned to
the
OFF
position.
If
the
brake switch
SW3
is
ON.
the
braking circuit
forces excitation
voltage
into
the
motor
field
winding, causing
the
armature
to
brake.
This
is
a
result
of
opposing
lines
of
flux
being
cut
6-25