Sorvall RT/T6000D - High Voltage Distribution

System
Descriptions: SORVALL®
Centrifuges
Electrical
6-7.
High Voltage
Distribution
(refer
to figure
6-5)
When
power
is
applied
to
the
centrifuge
by
setting
the
power
switch
CB
1
to
the
ON
or
"I"
position
(I),
the
mains
voltage
(115Vac/60Hz
or
220Vac/50Hz)
passes
through
CB1
and
divides into two
segments.
The first
segment
provides
power
to
the
compressor
assembly
for
refrigerated
centrifuges.
One
part
of the
mains
connects
directly to
one
side
of the
compressor assembly
through
P/J
10-1
and
a
second
part
connects through
Terminal
Block
TB1-1
and P/J
10-3.
The
second
part,
however,
is
interrupted
by
the
compressor
control
Triac
opto-isolator,
which
is found in
the
temperature
control
circuit.
When turned
on
by
the
"call
for
cool"
signal
from
the
temperature
control
circuit,
this
device
acts
as a
switch for the
mains
voltage
to
complete
its
path
through
the
compressor/fan
assembly.
NOTE
The
compressor/fan
assembly
for
115
Vac/60 Hz
centrifuges
uses a
115
Vac/60
Hz
power source.
The
compressor/fan
assembly
for
220
Vac/50
Hz
centrifuges uses a
220
Vac/50
Hz
power source.
The
second
mains
voltage segment
goes
to P/J3
pins
1
and
4.
On
115
Vac/60 Hz
centrifuges.
P/J
3 has
a
jumper
plug
inserted
that
routes
the
115
Vac
lines
into and back
out
of
the
plug.
This
jumper
is
used
only
when the
stepdown
transformer
T3
is not
used.
On
220Vac/50 Hz
centrifuges, transformer
T3
is installed in
place
ofthejumper
plug.
This
transformer
is used to
step
the
220
Vac voltage down to
115
Vac for the
low
voltage
power
transformer
Tl
(primary
side),
which
goes
through connection
P/J3
pins
2
and
3.
Power
transformer
Tl's
secondary
side
provides
two
(2)
different levels
of
voltage as
discussed
in the
next
paragraph,
6-8,
Low
Voltage
Distribution.
The
segment
of the
mains
voltage
that
is connected to terminal
1 of
the
Power
Transformer
(Tl)
goes
to
the
common
pin
of the Timer
Switch
(SW2). pin
8 of the
Run/Brake
Relay (Kl).
and terminates at
the
common
pin
of the
Brake
Switch
(SW3).
The
opposite
segment
(return
Segment),
which
is connected to
terminal
2
of
the
Power Transformer
(Tl), goes
to
one
side
of
the Timer
Motor.
It
provides
the
return path
when
the
Timer Switch
(SW2)
closes,
causing
the
timer
motor to begin
operation.
Another
branch from terminal
2
of the
Power Transformer
(Tl) is
connected to
terminal
7
of the
Run/Brake Relay (Kl).
In
the
de-energized
state,
it
connects
the brake circuitry
with
the
motor
through
the
relay.
A
connection
from terminal
7 of
the
Run/Brake Relay
(Kl)
goes
over to
the
Brake
Transformer
fT2)
by passing
through
P/J
16-3. From
there.
the
return
leg
of the
mains
voltage passes
through
a
thermal fuse located in
the
Brake
Transformer
(T2).
then
through
a
series
of
Plug/Jack
connections to
the brake control
Triac located
in
the
motor control circuit.
This
triac
is
gated
ON
whenever
the
speed
of
the
motor is above
200
rpm
and
the RUN/Brake
Relay
(Kl) is de-energized
(run
terminated
mode).
Braking is
then
provided only
if
the Brake Switch (SW3) is
set to
ON
or
"I"
position.
6-8