Dual 721 - System Architecture; System Block Diagram

A
slotless steel disk connected to
the rotor
acts as magnetic return.
The field windings of the
motor are ironless
and are embedded in
a plastic support. The
field
windings consist of 16 double wound
coils which are arranged in
two planes above
one another. The 8
coils of the lower plane
are 22.5 0 offset in relation
to the top pla—
ne. In each plane there
is a Hall generator
in the center of one
coil. The two Hall ge—
nerators are also
offset by 22.5
0
in rela—
tion to one another.
The individual
windings — 32 in all — are
connected
together so that four all round
phase windings
are produced.
Compared with other
directly—driven record
players in
the case of the Dual EDS
1000 mo—
tor no form of magnetic
drag or restoring
force is present
(pole jerk etc.) as can
easily be detected
by turning the
rotor. As
a
result of the
ironless field coils no
hy—
steresis or eddy
current losses or
interfe—
ring slot—ripple
frequencies
occur.
This
results in
completely
vibration—free
motor running
together with a
low power con—
sumption of
less than 50 mW
during play
(the
electronic
system is
not taken
into account).
By
virtue of
this
vibration—free running
the
motor can be
rigidly connected
to the chas—
sis. The
electronic
system
itself is
divided
into the
switch,
commutation and
control
sections
(see block diagram).
Fig. 4 Block Diagram
110-130 V
220-240 V
50-60 Hz
Supply unit
Netzteil
low ]
Gleichrichter
Rectif ier
Bloc secteur
Redresseur
Stoboskop
Elektronik
Strobe
Electronic
Stroboscopique
Electronique
Fig. 3 Line Board (Equipment Side)
Glimmlampe
Glim
lamp
Lampe
ä
effluves
Stabilisierung
Stabilization
Stabilisation
Netztran
sf ormator
Mains transfor mer
Transforrnateur de
riseau
• •
C 52 0047
II
.-ti-•
L___. D51
er iesmo,
Ill- Til
3 eo 68i;
9 - 1R51/22K I--•
T125mA
0
220 110V
Schalt- und
Regelteil
Switch and
control unit
Circuit et
pike- - 11---
de räglage
I
e e
220V/ SO -60
Hz
Drehzahlum-
schaltung und
Feinregulierung
Speed change et
fine
tuning
Changement
de
vitesse et
accord
präcis
7