Dual 502 - Motor and Drive System; Motor Pulley Replacement; Nominal Speed Adjustment

Fig. 2
Motor
and
Drive
Motor
and Drive
38 123 107
K
8
6 4
11 10
- ‘33111111W r
Fig. 3
Fig. 4 Motor
field coil
connections
220-240V
The turntable platter and the gear are dri—
ven by an 8 —pole, synchronous motor (123)
suspended by
radially located elastic mounts
and having a very small stray magnetic field
am well am little
vibration.
The speed of the motor is a function of li—
ne voltage, temperature and load
variations.
Speed is dependent on
and proportional to
line
frequency. The motor is adapted to 50
or 60 Hz (cps) by
the correct choice of mo—
tor pulley.
Pulley for
50 Hz, Part. No. 234
453
Pulley for
60 Hz, Part.
No. 234 454
The
drive is linked to the platter by a pre—
cision—ground belt (11). When replacing
the
flat belt (11) be sure
that the precision—
ground surface of the belt
(dull finish)
closely contacts the drive
pulley (107) and
the
platter.
Platter speeds of 33 1/3 and 45 rpm are
ad—
justed by linking the
flat belt (11) to the
corresponding step of the drive pulley (116)
(Fig. 3).
Corresponding to the
actuation of the speed
selector (12)
the control lever is brought
to the
appropriate position of nominal
speeds (33 1 / 3 or 45 rpm) via the change—
over lever
(101). When the unit is electri—
cally shut off
the changeover is blocked by
locking bar (7). Consequently,
the speed is
only preselected. After switching on the
unit and turning the platter (10) the lock—
ing bar (7) disengages the
changeover layer
thus guiding
the flat belt (11) to appropri—
ate step
of the pulley.
Replacement of Motor Pulley
1.
Remove flat belt (11) from motor pulley
(116). Undo machine screw (125) and sli—
de back locking bar (126). Remove platter
(10).
.2.
Loosen set screws (108) and
pull off dri—
ve
pulley (107).
3. Put complete
replacement drive pulley on
motor axle.
Remove conical sleeve.
Tigh—
ten set
screws (108) uniformly.
Place
conical sleeve into the
motor pulley
(107).
4. Put platter (10)
into bearing housing
(157) and
secure with lock bar (126).
Re—
tighten machine
screw (125). Put the
flat
belt on the
drive
pulley.
5. Check
nominal speed
with the strobe
disk.
If
necessary, readjust
as described
below.
Uni rig of nominal
speed
Lift platter mat (3) above one
of the reces—
ses (A) and turn platter (10) by hand so
that the drive pulley (107) becomes visible.
Hold the drive pulley (107) and turn the co—
nical sleeve (K).
If the nominal
speed is too high, turn the
conical sleeve (K) counterclockwise. If the
speed is too low turn the conical sleeve
clockwise.
Check by means of a strobe disk and repeat
adjustment, if necessary.
4