B-65302EN/01 SPECIFICATIONS FOR THE βiS SERIES 3.SELECTING A MOTOR
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[Example of calculation for condition 4-1] Example of calculation
Try to perform linear acceleration/deceleration under the
following condition.
V
m
=3000 [min
-1
]
t
a
=0.1 [s]
k
s
=30 [s
-1
]
J
L
=0.00334 [kg⋅m
2
]
Select the β8/3000is provisionally selected in example of
calculation <1>.
J
M
motor inertia is 0.00117 [kg⋅m
2
] when β8/3000is is selected,
so the load inertia is calculated as follows:
T
a
= 3000×(2π/60)×(1/0.1)×(0.00117+0.00334÷0.9)×(1-e
-30×0.1
)
= 14.6 [N⋅m] = 149 [kgf⋅cm]
V
r
= 3000×{1-1/(0.1×30)×(1-e
-30×0.1
)} = 2050 [min
-1
]
Acceleration torque in feed-forward during rapid traverse + bell-shaped
acceleration/deceleration
Torque
Speed
V
m
T
a
V
r
Time
Speed
Specified speed and actual
speed (nearly coincide with
each other)
V
m
t
1
t
1
+t
2
t
2
V
r
t
2
Time
cceleration
Acc
a
Point at which the
maximum torque is
required
When the feed-forward coefficient is large enough, the acceleration
torque in feed-forward during rapid traverse + bell-shaped
acceleration/deceleration can approximate to the value obtained with
the feed-forward coefficient = 1. When the feed-forward coefficient is
1, the equations for calculating the acceleration torque (T
a
), speed
(V
r
), and maximum workpiece acceleration (Acc
a
) are given below: