Toshiba 4580, Service Manual

Page: 97 / 379

Mar. 1999 © TOSHIBA TEC 7 - 7 6570/5570 SCANNER
The stator comprises 10 main poles, with two main poles in apposition forming a single phase. The coil
is wound so that the two opposite main poles are the same polarity (N or S). Assuming a rotor tooth pitch
of
τ
R
, the stator teeth are arranged in such a way that the stator teeth on adjacent main poles shift by 0.6
τ
R
with respect to the rotor teeth. This means that the stator teeth on adjacent main poles shift by (0.6-
0.5)
τ
R
=
τ
R
/10 with respect to teeth on the rotor cup on the opposite side that are shifted by 0.5
τ
R
. Fig.
7.4-2 illustrates this relationship.
Consequently, if the polarity of the stator is moved as shown in Fig. 7.4-3, the rotor rotates clockwise 1/
10th of the rotor tooth pitch at a time.
Fig. 7.4-2 Relationship between Stator Teeth and Rotor Teeth
Fig. 7.4-3 Movement of Poles at 1-phase Excitation
τ
R
10
360
50
1
10
0.5
0.6
10
τ
τ
R
R
τ
R
1
N
A Phase Phase Phase Phase Phase
Phase Phase
Phase Phase Phase
1
N
S
B
2
S
N
C
3
N
S
D
4
S
N
E
5
N
S
A
6
S
N
B
7
N
S
C
8
S
N
D
9
N
S
E
10
S
Stator
Rotor
=
×
= 0.72° ...................... (1)