
B–65160E/02
2. FUNCTION EXPLANATION
FANUC AC SPINDLE MOTOR a series
77
(d) Speed Nms [min
–1
] is calculated as follows:
Nms +
L
2
1
2pH
60 PG
where,
L : Length of the magnetizing element [mm]
H: Distance from the center of the spindle to the magnetizing
element [mm]
t
4
is the time required to rotate (L/2)/2 H turns at speed Nms.
t
4
+
(L 2) 2pH
Nms
60 +
1
PG
(e) Let the orientation completion width be within "1_. Then, t
3
and
t
5
are expressed as follows:
t
3
)t
5
+
1
PG
In (360 Rori)
(f) Therefore, orientation time t [sec] (= t
1
+ t
2
+ t
3
+ t
4
+ t
5
) can be
expressed as follows:
t
1
)
1
PG Rori
)
1
PG
In (360 Rori) x t x t
1
)
2
PG Rori
)
1
PG
In (360 Rori)
(2) Calculation example
Time required to achieve the orientation speed t
1
= 0.5 [sec]
Position gain PG = 20 [sec
–1
]
Motor speed limit ratio for orientation Rori = 0.33 (= 33%)
Then, orientation time t [sec] is obtained as follows:
0.5)
1
20 0.33
)
1
20
In (360 0.33) x t x 0.5)
2
20 0.33
)
1
20
In (360 0.33)
N 0.890 [sec] x t x 1.042 [sec]