Mitsubishi Electronics IB-1500193(ENG)-D ユーザーズマニュアル
5 - 12
5 Spindle Adjustment
MITSUBISHI CNC
5-2-3 Adjusting the acceleration/deceleration operation
(1) Calculating the theoretical acceleration/deceleration time
The spindle motor output characteristics (shown on the right)
have three ranges, which are constant torque, constant output,
and deceleration ranges. Each range has different calculation
method. The acceleration/deceleration time is calculated using
the calculation expression which corresponds to each range of
the rotation speed for calculation. Note that the load torque
(friction torque) is not considered in the calculation expression, so
the result may slightly differ from the actual acceleration/
deceleration time.
(a) Maximum motor output during acceleration/deceleration: Po
During acceleration/deceleration, the output is 1.2-fold the short-time rating.
The output Po during acceleration/deceleration follows the expression below.
Po = (Short-time rated output) x 1.2 [W]
Substitute this value into Po of the expression.
(b) Total load inertia: J
all
Total load inertia means the total inertia of the spindle motor and of the components which are
rotated the motor (shaft, etc.).
J
all
= (Motor inertia) + (Spindle conversion inertia) [kg•m
2
]
The values obtained in (a) and (b) are substituted into the following calculation expressions.
To calculate the acceleration/deceleration time of the rotation speed N (r/min), use the expression
(c), (d) or (e) which is selected depending on the range that corresponds to the speed N.
(c) Acceleration/deceleration time for constant torque range: t1···0 to N [r/min] (0
N
N1)
(For N>N1, apply N=N1 and also calculate t2 or t3.)
(d) Acceleration/deceleration time for constant output range: t2···N1 to N [r/min] (N1<N
N2)
(For N>N2, apply N=N2 and also calculate t3.)
(e) Acceleration/deceleration time in deceleration output range: t3···N2 to N [r/min] (N2<N
N3)
Based on the above expressions, the acceleration/deceleration time: t from 0 to N3 [r/min] is:
t = t1 + t2 + t3 [s] (Caution 2)
Out
p
ut
[
W
]
Output characteristics for
acceleration/deceleration
acceleration/deceleration
0
N1
N2
0
N3
Po
Rotation speed [r/min ]
Short -time rating ×1.2
Constant
output range
Constant torque range
Deceleration
range
range
≦
≦
1.097 x 10
-2
x J
all
x N1 x N
t1 =
Po
[s]
(Caution 1)
≦
1.097 x 10
-2
x J
all
x (N
2
- N1
2
)
t2 =
2 x Po
[s]
(Caution 1)
≦
1.097 x 10
-2
x J
all
x (N
3
- N2
3
)
t3 =
3 x Po x N2
[s]
(Caution 1)