Hitachi RAC-18SX8 Service Manual page 137

8. Stepping motor drive circuit
Microcomputer
Ⅰ Ｃ601
Front panel
− φ4
Front panel
− φ3
Front panel − φ2
Front panel − φ1
Lateral vane, left
− φ4
Lateral vane, left
− φ3
Lateral vane, left
− φ2
Lateral vane, left
− φ1
Lateral vane, right
− φ4
Lateral vane, right
− φ3
Lateral vane, right
− φ2
Lateral vane, right − φ1
Vertical vane, small
− φ4
Vertical vane, small
− φ3
Vertical vane, small
− φ2
Vertical vane, small
− φ1
Vertical vane, big
− φ4
Vertical vane, big
− φ3
Vertical vane, big
− φ2
Vertical vane, big − φ1
[Connector circuit waveform while the motor runs]
Voltage waveforms of different phases as viewed from
the OV line while the motor rotor is turning counterclockwise
as viewed from the shaft side
φ4 terminal
φ3 terminal
φ2 terminal
φ1 terminal
・Each stepping motor runs as excited in 1 or 2 phases at 100 PPS or 200 PPS.
・The excitation pattern passes the microcomputer (IC601) and then the driver IC and excites the coil of each stepping motor.
Driver IC
86
85
84
83
80
79
78
77
76
75
74
73
28
27
26
25
24
23
22
21
5 ms. or 10 ms.
Fig. 8-2
12V
Ｃ Ｎ18
Ｃ Ｎ12
Ｃ Ｎ １ ５
Fig. 8-1
– 170 –
12Ｖ
1
φ4
2
φ3
Ｍ
3
φ2
4
φ1
5
Front panel motor
12Ｖ
1
φ4
2
φ3
Ｍ
3
φ2
4
φ1
5
Lateral vane motor, left
12Ｖ
6
φ4
7
φ3
Ｍ
8
φ2
9
φ1
10
Lateral vane motor, right
12Ｖ
1
φ4
2
φ3
Ｍ
3
φ2
4
φ1
5
Motor for vertical vane, small
12Ｖ
6
φ4
7
φ3
Ｍ
8
φ2
9
φ1
10
Motor for vertical vane, big